Library UniMath.CategoryTheory.DisplayedCats.Fibrations
Definitions of various kinds of fibrations, using displayed categories.
Require Import UniMath.Foundations.Sets.
Require Import UniMath.MoreFoundations.All.
Require Import UniMath.CategoryTheory.Core.Categories.
Require Import UniMath.CategoryTheory.Core.Isos.
Require Import UniMath.CategoryTheory.Core.NaturalTransformations.
Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.Core.Functors.
Require Import UniMath.CategoryTheory.categories.HSET.Core.
Require Import UniMath.CategoryTheory.categories.HSET.MonoEpiIso.
Require Import UniMath.CategoryTheory.categories.HSET.Univalence.
Require Import UniMath.CategoryTheory.limits.pullbacks.
Require Import UniMath.CategoryTheory.Adjunctions.Core.
Require Import UniMath.CategoryTheory.Equivalences.Core.
Require Import UniMath.CategoryTheory.FunctorCategory.
Require Import UniMath.CategoryTheory.opp_precat.
Require Import UniMath.CategoryTheory.Presheaf.
Local Open Scope cat.
Require Import UniMath.CategoryTheory.DisplayedCats.Core.
Require Import UniMath.CategoryTheory.DisplayedCats.Functors.
Require Import UniMath.CategoryTheory.DisplayedCats.NaturalTransformations.
Require Import UniMath.CategoryTheory.DisplayedCats.Fiber.
Require Import UniMath.CategoryTheory.DisplayedCats.Isos.
Require Import UniMath.CategoryTheory.DisplayedCats.Univalence.
Require Import UniMath.CategoryTheory.DisplayedCats.Examples.Opposite.
Local Open Scope type_scope.
Local Open Scope mor_disp_scope.
Fibratons, opfibrations, and isofibrations are all displayed categories with extra lifting conditions.
Classically, these lifting conditions are usually taken by default as mere existence conditions; when they are given by operations, one speaks of a cloven fibration, etc.
We make the cloven version the default, so is_fibration etc are the cloven notions, and call the mere-existence versions un-cloven.
(This conventional is provisional and and might change in future.)
The easiest to define are isofibrations, since they do not depend on a definition of (co-)cartesian-ness (because all displayed isomorphisms are cartesian).
Isofibrations
Given an iso φ : c' =~ c in C, and an object d in D c,
there’s some object d' in D c', and an iso φbar : d' =~ d over φ.
Definition iso_cleaving {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (i : z_iso c' c) (d : D c),
∑ d' : D c', z_iso_disp i d' d.
Definition iso_fibration (C : category) : UU
:= ∑ D : disp_cat C, iso_cleaving D.
Definition is_uncloven_iso_cleaving {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (i : z_iso c' c) (d : D c),
∃ d' : D c', z_iso_disp i d' d.
Definition weak_iso_fibration (C : category) : UU
:= ∑ D : disp_cat C, is_uncloven_iso_cleaving D.
As with fibrations, there is an evident dual version. However, in the iso case, it is self-dual: having forward (i.e. cocartesian) liftings along isos is equivalent to having backward (cartesian) liftings.
Definition is_op_isofibration {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (i : z_iso c c') (d : D c),
∑ d' : D c', z_iso_disp i d d'.
Lemma is_isofibration_iff_is_op_isofibration
{C : category} (D : disp_cat C)
: iso_cleaving D <-> is_op_isofibration D.
Show proof.
Section Fibrations.
Definition is_cartesian {C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} (ff : d' -->[f] d)
: UU
:= forall c'' (g : c'' --> c') (d'' : D c'') (hh : d'' -->[g·f] d),
∃! (gg : d'' -->[g] d'), gg ;; ff = hh.
Definition is_cartesian {C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} (ff : d' -->[f] d)
: UU
:= forall c'' (g : c'' --> c') (d'' : D c'') (hh : d'' -->[g·f] d),
∃! (gg : d'' -->[g] d'), gg ;; ff = hh.
See also cartesian_factorisation' below, for when the map one wishes to factor is not judgementally over g;;f, but over some equal map.
Definition cartesian_factorisation {C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c') {d'' : D c''} (hh : d'' -->[g·f] d)
: d'' -->[g] d'
:= pr1 (pr1 (H _ g _ hh)).
Definition cartesian_factorisation_commutes
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c') {d'' : D c''} (hh : d'' -->[g·f] d)
: cartesian_factorisation H g hh ;; ff = hh
:= pr2 (pr1 (H _ g _ hh)).
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c') {d'' : D c''} (hh : d'' -->[g·f] d)
: d'' -->[g] d'
:= pr1 (pr1 (H _ g _ hh)).
Definition cartesian_factorisation_commutes
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c') {d'' : D c''} (hh : d'' -->[g·f] d)
: cartesian_factorisation H g hh ;; ff = hh
:= pr2 (pr1 (H _ g _ hh)).
While cartesian_factorisation_commutes shows that composition with and factorisation through a cartesian morphism are one-sided inverses in one direction, the following shows the other direction.
Definition cartesian_factorisation_of_composite
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c'' : C} {g : c'' --> c'} {d'' : D c''} (gg : d'' -->[g] d')
: gg = cartesian_factorisation H g (gg ;; ff).
Proof.
exact (maponpaths pr1 (pr2 (H _ _ _ _) (_,, idpath _))).
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c'' : C} {g : c'' --> c'} {d'' : D c''} (gg : d'' -->[g] d')
: gg = cartesian_factorisation H g (gg ;; ff).
Proof.
exact (maponpaths pr1 (pr2 (H _ _ _ _) (_,, idpath _))).
This is essentially the third access function for is_cartesian, but given in a more usable form than pr2 (H …) would be.
Definition cartesian_factorisation_unique
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} {g : c'' --> c'} {d'' : D c''} (gg gg' : d'' -->[g] d')
: (gg ;; ff = gg' ;; ff) -> gg = gg'.
Show proof.
Definition cartesian_factorisation' {C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c')
{h : c'' --> c} {d'' : D c''} (hh : d'' -->[h] d)
(e : (g · f = h))
: d'' -->[g] d'.
Show proof.
Definition cartesian_factorisation_commutes'
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c')
{h : c'' --> c} {d'' : D c''} (hh : d'' -->[h] d)
(e : (g · f = h))
: (cartesian_factorisation' H g hh e) ;; ff
= transportb _ e hh.
Show proof.
Definition cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
: UU
:= ∑ (d' : D c') (ff : d' -->[f] d), is_cartesian ff.
Definition object_of_cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: D c'
:= pr1 fd.
Coercion object_of_cartesian_lift : cartesian_lift >-> ob_disp.
Definition mor_disp_of_cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: (fd : D c') -->[f] d
:= pr1 (pr2 fd).
Coercion mor_disp_of_cartesian_lift : cartesian_lift >-> mor_disp.
Definition cartesian_lift_is_cartesian {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: is_cartesian fd
:= pr2 (pr2 fd).
Coercion cartesian_lift_is_cartesian : cartesian_lift >-> is_cartesian.
Definition is_cartesian_disp_functor
{C C' : category} {F : functor C C'}
{D : disp_cat C} {D' : disp_cat C'} (FF : disp_functor F D D') : UU
:= ∏ (c c' : C) (f : c' --> c)
(d : D c) (d' : D c') (ff : d' -->[f] d),
is_cartesian ff -> is_cartesian (♯ FF ff).
Definition disp_functor_identity_is_cartesian_disp_functor
{C : category}
(D : disp_cat C)
: is_cartesian_disp_functor (disp_functor_identity D).
Show proof.
Definition disp_functor_composite_is_cartesian_disp_functor
{C₁ C₂ C₃ : category}
{F : C₁ ⟶ C₂}
{G : C₂ ⟶ C₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{D₃ : disp_cat C₃}
{FF : disp_functor F D₁ D₂}
{GG : disp_functor G D₂ D₃}
(HFF : is_cartesian_disp_functor FF)
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor (disp_functor_composite FF GG).
Show proof.
Definition disp_functor_over_id_composite_is_cartesian
{C : category}
{D₁ D₂ D₃ : disp_cat C}
{FF : disp_functor (functor_identity C) D₁ D₂}
{GG : disp_functor (functor_identity C) D₂ D₃}
(HFF : is_cartesian_disp_functor FF)
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor (disp_functor_over_id_composite FF GG).
Show proof.
Definition cartesian_disp_functor
{C₁ C₂ : category}
(F : C₁ ⟶ C₂)
(D₁ : disp_cat C₁)
(D₂ : disp_cat C₂)
: UU
:= ∑ (FF : disp_functor F D₁ D₂), is_cartesian_disp_functor FF.
Coercion disp_functor_of_cartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : cartesian_disp_functor F D₁ D₂)
: disp_functor F D₁ D₂
:= pr1 FF.
Definition cartesian_disp_functor_is_cartesian
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : cartesian_disp_functor F D₁ D₂)
: is_cartesian_disp_functor FF
:= pr2 FF.
Definition cartesian_disp_functor_on_cartesian
{C : category}
{D₁ D₂ : disp_cat C}
(F : cartesian_disp_functor (functor_identity C) D₁ D₂)
{x y : C}
{f : x --> y}
{xx : D₁ x}
{yy : D₁ y}
{ff : xx -->[ f ] yy}
(Hff : is_cartesian ff)
: is_cartesian (♯ F ff)
:= pr2 F y x f yy xx ff Hff.
Lemma isaprop_is_cartesian
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} (ff : d' -->[f] d)
: isaprop (is_cartesian ff).
Show proof.
Proposition isaprop_is_cartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : disp_functor F D₁ D₂)
: isaprop (is_cartesian_disp_functor FF).
Show proof.
Definition cleaving {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (f : c' --> c) (d : D c), cartesian_lift d f.
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} {g : c'' --> c'} {d'' : D c''} (gg gg' : d'' -->[g] d')
: (gg ;; ff = gg' ;; ff) -> gg = gg'.
Show proof.
intro Hggff.
eapply pathscomp0. apply (cartesian_factorisation_of_composite H).
eapply pathscomp0. apply maponpaths, Hggff.
apply pathsinv0, cartesian_factorisation_of_composite.
eapply pathscomp0. apply (cartesian_factorisation_of_composite H).
eapply pathscomp0. apply maponpaths, Hggff.
apply pathsinv0, cartesian_factorisation_of_composite.
Definition cartesian_factorisation' {C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c')
{h : c'' --> c} {d'' : D c''} (hh : d'' -->[h] d)
(e : (g · f = h))
: d'' -->[g] d'.
Show proof.
Definition cartesian_factorisation_commutes'
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} {ff : d' -->[f] d} (H : is_cartesian ff)
{c''} (g : c'' --> c')
{h : c'' --> c} {d'' : D c''} (hh : d'' -->[h] d)
(e : (g · f = h))
: (cartesian_factorisation' H g hh e) ;; ff
= transportb _ e hh.
Show proof.
Definition cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
: UU
:= ∑ (d' : D c') (ff : d' -->[f] d), is_cartesian ff.
Definition object_of_cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: D c'
:= pr1 fd.
Coercion object_of_cartesian_lift : cartesian_lift >-> ob_disp.
Definition mor_disp_of_cartesian_lift {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: (fd : D c') -->[f] d
:= pr1 (pr2 fd).
Coercion mor_disp_of_cartesian_lift : cartesian_lift >-> mor_disp.
Definition cartesian_lift_is_cartesian {C : category} {D : disp_cat C}
{c} (d : D c) {c' : C} (f : c' --> c)
(fd : cartesian_lift d f)
: is_cartesian fd
:= pr2 (pr2 fd).
Coercion cartesian_lift_is_cartesian : cartesian_lift >-> is_cartesian.
Definition is_cartesian_disp_functor
{C C' : category} {F : functor C C'}
{D : disp_cat C} {D' : disp_cat C'} (FF : disp_functor F D D') : UU
:= ∏ (c c' : C) (f : c' --> c)
(d : D c) (d' : D c') (ff : d' -->[f] d),
is_cartesian ff -> is_cartesian (♯ FF ff).
Definition disp_functor_identity_is_cartesian_disp_functor
{C : category}
(D : disp_cat C)
: is_cartesian_disp_functor (disp_functor_identity D).
Show proof.
intros x y f xx yy ff Hff.
exact Hff.
exact Hff.
Definition disp_functor_composite_is_cartesian_disp_functor
{C₁ C₂ C₃ : category}
{F : C₁ ⟶ C₂}
{G : C₂ ⟶ C₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{D₃ : disp_cat C₃}
{FF : disp_functor F D₁ D₂}
{GG : disp_functor G D₂ D₃}
(HFF : is_cartesian_disp_functor FF)
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor (disp_functor_composite FF GG).
Show proof.
intros x y f xx yy ff Hff.
apply HGG.
apply HFF.
exact Hff.
apply HGG.
apply HFF.
exact Hff.
Definition disp_functor_over_id_composite_is_cartesian
{C : category}
{D₁ D₂ D₃ : disp_cat C}
{FF : disp_functor (functor_identity C) D₁ D₂}
{GG : disp_functor (functor_identity C) D₂ D₃}
(HFF : is_cartesian_disp_functor FF)
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor (disp_functor_over_id_composite FF GG).
Show proof.
intros x y f xx yy ff Hff.
apply HGG.
apply HFF.
exact Hff.
apply HGG.
apply HFF.
exact Hff.
Definition cartesian_disp_functor
{C₁ C₂ : category}
(F : C₁ ⟶ C₂)
(D₁ : disp_cat C₁)
(D₂ : disp_cat C₂)
: UU
:= ∑ (FF : disp_functor F D₁ D₂), is_cartesian_disp_functor FF.
Coercion disp_functor_of_cartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : cartesian_disp_functor F D₁ D₂)
: disp_functor F D₁ D₂
:= pr1 FF.
Definition cartesian_disp_functor_is_cartesian
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : cartesian_disp_functor F D₁ D₂)
: is_cartesian_disp_functor FF
:= pr2 FF.
Definition cartesian_disp_functor_on_cartesian
{C : category}
{D₁ D₂ : disp_cat C}
(F : cartesian_disp_functor (functor_identity C) D₁ D₂)
{x y : C}
{f : x --> y}
{xx : D₁ x}
{yy : D₁ y}
{ff : xx -->[ f ] yy}
(Hff : is_cartesian ff)
: is_cartesian (♯ F ff)
:= pr2 F y x f yy xx ff Hff.
Lemma isaprop_is_cartesian
{C : category} {D : disp_cat C}
{c c' : C} {f : c' --> c}
{d : D c} {d' : D c'} (ff : d' -->[f] d)
: isaprop (is_cartesian ff).
Show proof.
Proposition isaprop_is_cartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : disp_functor F D₁ D₂)
: isaprop (is_cartesian_disp_functor FF).
Show proof.
Definition cleaving {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (f : c' --> c) (d : D c), cartesian_lift d f.
Definition is_cleaving {C : category} (D : disp_cat C) : UU
:=
forall (c c' : C) (f : c' --> c) (d : D c), ∥ cartesian_lift d f ∥.
Definition weak_fibration (C : category) : UU
:= ∑ D : disp_cat C, is_cleaving D.
Lemma is_z_iso_from_is_cartesian {C : category} {D : disp_cat C}
{c c' : C} (i : z_iso c' c) {d : D c} {d'} (ff : d' -->[i] d)
: is_cartesian ff -> is_z_iso_disp i ff.
Show proof.
intros Hff.
use (_,,_); try split.
- use
(cartesian_factorisation' Hff (inv_from_z_iso i) (id_disp _)).
apply z_iso_after_z_iso_inv.
- apply cartesian_factorisation_commutes'.
- apply (cartesian_factorisation_unique Hff).
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind.
etrans. apply mor_disp_transportf_prewhisker.
eapply transportf_bind, id_right_disp.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
etrans. eapply transportf_bind, id_left_disp.
apply maponpaths_2, homset_property.
use (_,,_); try split.
- use
(cartesian_factorisation' Hff (inv_from_z_iso i) (id_disp _)).
apply z_iso_after_z_iso_inv.
- apply cartesian_factorisation_commutes'.
- apply (cartesian_factorisation_unique Hff).
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind.
etrans. apply mor_disp_transportf_prewhisker.
eapply transportf_bind, id_right_disp.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
etrans. eapply transportf_bind, id_left_disp.
apply maponpaths_2, homset_property.
Lemma is_isofibration_from_is_fibration {C : category} {D : disp_cat C}
: cleaving D -> iso_cleaving D.
Show proof.
intros D_fib c c' f d.
assert (fd := D_fib _ _ f d).
exists (fd : D _).
exists (fd : _ -->[_] _).
apply is_z_iso_from_is_cartesian; exact fd.
assert (fd := D_fib _ _ f d).
exists (fd : D _).
exists (fd : _ -->[_] _).
apply is_z_iso_from_is_cartesian; exact fd.
Definition cartesian_lifts_iso {C : category} {D : disp_cat C}
{c} {d : D c} {c' : C} {f : c' --> c} (fd fd' : cartesian_lift d f)
: z_iso_disp (identity_z_iso c') fd fd'.
Show proof.
use (_,,(_,,_)).
- exact (cartesian_factorisation' fd' (identity _) fd (id_left _)).
- exact (cartesian_factorisation' fd (identity _) fd' (id_left _)).
- cbn; split.
+ apply (cartesian_factorisation_unique fd').
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind, mor_disp_transportf_prewhisker.
rewrite cartesian_factorisation_commutes'.
etrans. apply transport_f_f.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
rewrite id_left_disp.
etrans. apply transport_f_f.
apply maponpaths_2, homset_property.
+ apply (cartesian_factorisation_unique fd).
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind, mor_disp_transportf_prewhisker.
rewrite cartesian_factorisation_commutes'.
etrans. apply transport_f_f.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
rewrite id_left_disp.
etrans. apply transport_f_f.
apply maponpaths_2, homset_property.
- exact (cartesian_factorisation' fd' (identity _) fd (id_left _)).
- exact (cartesian_factorisation' fd (identity _) fd' (id_left _)).
- cbn; split.
+ apply (cartesian_factorisation_unique fd').
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind, mor_disp_transportf_prewhisker.
rewrite cartesian_factorisation_commutes'.
etrans. apply transport_f_f.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
rewrite id_left_disp.
etrans. apply transport_f_f.
apply maponpaths_2, homset_property.
+ apply (cartesian_factorisation_unique fd).
etrans. apply assoc_disp_var.
rewrite cartesian_factorisation_commutes'.
etrans. eapply transportf_bind, mor_disp_transportf_prewhisker.
rewrite cartesian_factorisation_commutes'.
etrans. apply transport_f_f.
apply pathsinv0.
etrans. apply mor_disp_transportf_postwhisker.
rewrite id_left_disp.
etrans. apply transport_f_f.
apply maponpaths_2, homset_property.
Definition cartesian_lifts_iso_commutes {C : category} {D : disp_cat C}
{c} {d : D c} {c' : C} {f : c' --> c} (fd fd' : cartesian_lift d f)
: (cartesian_lifts_iso fd fd') ;; fd'
= transportb _ (id_left _) (fd : _ -->[_] _).
Show proof.
In a displayed category (i.e. univalent), cartesian lifts are literally unique, if they exist; that is, the type of cartesian lifts is always a proposition.
Definition isaprop_cartesian_lifts
{C : category} {D : disp_cat C} (D_cat : is_univalent_disp D)
{c} (d : D c) {c' : C} (f : c' --> c)
: isaprop (cartesian_lift d f).
Show proof.
Definition univalent_fibration_is_cloven
{C : category} {D : disp_cat C} (D_cat : is_univalent_disp D)
: is_cleaving D -> cleaving D.
Show proof.
End Fibrations.
Definition isaprop_cleaving
{C : univalent_category}
(D : disp_cat C)
(HD : is_univalent_disp D)
: isaprop (cleaving D).
Show proof.
Section Discrete_Fibrations.
Definition is_discrete_fibration {C : category} (D : disp_cat C) : UU
:=
(forall (c c' : C) (f : c' --> c) (d : D c),
∃! d' : D c', d' -->[f] d)
×
(forall c, isaset (D c)).
Definition discrete_fibration C : UU
:= ∑ D : disp_cat C, is_discrete_fibration D.
Coercion disp_cat_from_discrete_fibration C (D : discrete_fibration C)
: disp_cat C := pr1 D.
Definition unique_lift {C} {D : discrete_fibration C} {c c'}
(f : c' --> c) (d : D c)
: ∃! d' : D c', d' -->[f] d
:= pr1 (pr2 D) c c' f d.
Definition isaset_fiber_discrete_fibration {C} (D : discrete_fibration C)
(c : C) : isaset (D c) := pr2 (pr2 D) c.
{C : category} {D : disp_cat C} (D_cat : is_univalent_disp D)
{c} (d : D c) {c' : C} (f : c' --> c)
: isaprop (cartesian_lift d f).
Show proof.
apply invproofirrelevance; intros fd fd'.
use total2_paths_f.
{ apply (isotoid_disp D_cat (idpath _)); cbn.
apply cartesian_lifts_iso. }
apply subtypePath.
{ intros ff. repeat (apply impred; intro).
apply isapropiscontr. }
etrans.
{ exact (! transport_map (λ x:D c', pr1) _ _). }
cbn. etrans. apply transportf_precompose_disp.
rewrite idtoiso_isotoid_disp.
use (pathscomp0 (maponpaths _ _) (transportfbinv _ _ _)).
apply (precomp_with_z_iso_disp_is_inj (cartesian_lifts_iso fd fd')).
etrans. apply assoc_disp.
etrans. eapply transportf_bind, cancel_postcomposition_disp.
use inv_mor_after_z_iso_disp.
etrans. eapply transportf_bind, id_left_disp.
apply pathsinv0.
etrans. apply mor_disp_transportf_prewhisker.
etrans. eapply transportf_bind, cartesian_lifts_iso_commutes.
apply maponpaths_2, homset_property.
use total2_paths_f.
{ apply (isotoid_disp D_cat (idpath _)); cbn.
apply cartesian_lifts_iso. }
apply subtypePath.
{ intros ff. repeat (apply impred; intro).
apply isapropiscontr. }
etrans.
{ exact (! transport_map (λ x:D c', pr1) _ _). }
cbn. etrans. apply transportf_precompose_disp.
rewrite idtoiso_isotoid_disp.
use (pathscomp0 (maponpaths _ _) (transportfbinv _ _ _)).
apply (precomp_with_z_iso_disp_is_inj (cartesian_lifts_iso fd fd')).
etrans. apply assoc_disp.
etrans. eapply transportf_bind, cancel_postcomposition_disp.
use inv_mor_after_z_iso_disp.
etrans. eapply transportf_bind, id_left_disp.
apply pathsinv0.
etrans. apply mor_disp_transportf_prewhisker.
etrans. eapply transportf_bind, cartesian_lifts_iso_commutes.
apply maponpaths_2, homset_property.
Definition univalent_fibration_is_cloven
{C : category} {D : disp_cat C} (D_cat : is_univalent_disp D)
: is_cleaving D -> cleaving D.
Show proof.
intros D_fib c c' f d.
apply (squash_to_prop (D_fib c c' f d)).
apply isaprop_cartesian_lifts; assumption.
auto.
apply (squash_to_prop (D_fib c c' f d)).
apply isaprop_cartesian_lifts; assumption.
auto.
End Fibrations.
Definition isaprop_cleaving
{C : univalent_category}
(D : disp_cat C)
(HD : is_univalent_disp D)
: isaprop (cleaving D).
Show proof.
Section Discrete_Fibrations.
Definition is_discrete_fibration {C : category} (D : disp_cat C) : UU
:=
(forall (c c' : C) (f : c' --> c) (d : D c),
∃! d' : D c', d' -->[f] d)
×
(forall c, isaset (D c)).
Definition discrete_fibration C : UU
:= ∑ D : disp_cat C, is_discrete_fibration D.
Coercion disp_cat_from_discrete_fibration C (D : discrete_fibration C)
: disp_cat C := pr1 D.
Definition unique_lift {C} {D : discrete_fibration C} {c c'}
(f : c' --> c) (d : D c)
: ∃! d' : D c', d' -->[f] d
:= pr1 (pr2 D) c c' f d.
Definition isaset_fiber_discrete_fibration {C} (D : discrete_fibration C)
(c : C) : isaset (D c) := pr2 (pr2 D) c.
TODO: move upstream
Lemma pair_inj {A : UU} {B : A -> UU} (is : isaset A) {a : A}
{b b' : B a} : (a,,b) = (a,,b') -> b = b'.
Show proof.
Lemma disp_mor_unique_disc_fib C (D : discrete_fibration C)
: ∏ (c c' : C) (f : c --> c') (d : D c) (d' : D c')
(ff ff' : d -->[f] d'), ff = ff'.
Show proof.
Lemma isaprop_disc_fib_hom C (D : discrete_fibration C)
: ∏ (c c' : C) (f : c --> c') (d : D c) (d' : D c'),
isaprop (d -->[f] d').
Show proof.
Definition fibration_from_discrete_fibration C (D : discrete_fibration C)
: cleaving D.
Show proof.
Section Equivalence_disc_fibs_presheaves.
Variable C : category.
Definition precat_of_discrete_fibs_ob_mor : precategory_ob_mor.
Show proof.
Definition precat_of_discrete_fibs_data : precategory_data.
Show proof.
Lemma eq_discrete_fib_mor (F G : precat_of_discrete_fibs_ob_mor)
(a b : F --> G)
(H : ∏ x y, pr1 (pr1 a) x y = pr1 (pr1 b) x y)
: a = b.
Show proof.
Definition precat_axioms_of_discrete_fibs : is_precategory precat_of_discrete_fibs_data.
Show proof.
Definition precat_of_discrete_fibs : precategory
:= (_ ,, precat_axioms_of_discrete_fibs).
Lemma has_homsets_precat_of_discrete_fibs : has_homsets precat_of_discrete_fibs.
Show proof.
Definition Precat_of_discrete_fibs : category
:= ( precat_of_discrete_fibs ,, has_homsets_precat_of_discrete_fibs).
{b b' : B a} : (a,,b) = (a,,b') -> b = b'.
Show proof.
Lemma disp_mor_unique_disc_fib C (D : discrete_fibration C)
: ∏ (c c' : C) (f : c --> c') (d : D c) (d' : D c')
(ff ff' : d -->[f] d'), ff = ff'.
Show proof.
intros.
assert (XR := unique_lift f d').
assert (foo : ((d,,ff) : ∑ d0, d0 -->[f] d') = (d,,ff')).
{ apply proofirrelevancecontr. apply XR. }
apply (pair_inj (isaset_fiber_discrete_fibration _ _ ) foo).
assert (XR := unique_lift f d').
assert (foo : ((d,,ff) : ∑ d0, d0 -->[f] d') = (d,,ff')).
{ apply proofirrelevancecontr. apply XR. }
apply (pair_inj (isaset_fiber_discrete_fibration _ _ ) foo).
Lemma isaprop_disc_fib_hom C (D : discrete_fibration C)
: ∏ (c c' : C) (f : c --> c') (d : D c) (d' : D c'),
isaprop (d -->[f] d').
Show proof.
Definition fibration_from_discrete_fibration C (D : discrete_fibration C)
: cleaving D.
Show proof.
intros c c' f d.
use tpair.
- exact (pr1 (iscontrpr1 (unique_lift f d))).
- use tpair.
+ exact (pr2 (iscontrpr1 (unique_lift f d))).
+ intros c'' g db hh.
set (ff := pr2 (iscontrpr1 (unique_lift f d)) ). cbn in ff.
set (d' := pr1 (iscontrpr1 (unique_lift f d))) in *.
set (ggff := pr2 (iscontrpr1 (unique_lift (g·f) d)) ). cbn in ggff.
set (d'' := pr1 (iscontrpr1 (unique_lift (g·f) d))) in *.
set (gg := pr2 (iscontrpr1 (unique_lift g d'))). cbn in gg.
set (d3 := pr1 (iscontrpr1 (unique_lift g d'))) in *.
assert (XR : ((d'',, ggff) : ∑ r, r -->[g·f] d) = (db,,hh)).
{ apply proofirrelevancecontr. apply (pr2 D). }
assert (XR1 : ((d'',, ggff) : ∑ r, r -->[g·f] d) = (d3 ,,gg;;ff)).
{ apply proofirrelevancecontr. apply (pr2 D). }
assert (XT := maponpaths pr1 XR). cbn in XT.
assert (XT1 := maponpaths pr1 XR1). cbn in XT1.
generalize XR.
generalize XR1; clear XR1.
destruct XT.
generalize gg; clear gg.
destruct XT1.
intros gg XR1 XR0.
apply iscontraprop1.
* apply invproofirrelevance.
intros x x'. apply subtypePath.
{ intro. apply homsets_disp. }
apply disp_mor_unique_disc_fib.
* exists gg.
cbn.
assert (XX := pair_inj (isaset_fiber_discrete_fibration _ _ ) XR1).
assert (YY := pair_inj (isaset_fiber_discrete_fibration _ _ ) XR0).
etrans. apply (!XX). apply YY.
use tpair.
- exact (pr1 (iscontrpr1 (unique_lift f d))).
- use tpair.
+ exact (pr2 (iscontrpr1 (unique_lift f d))).
+ intros c'' g db hh.
set (ff := pr2 (iscontrpr1 (unique_lift f d)) ). cbn in ff.
set (d' := pr1 (iscontrpr1 (unique_lift f d))) in *.
set (ggff := pr2 (iscontrpr1 (unique_lift (g·f) d)) ). cbn in ggff.
set (d'' := pr1 (iscontrpr1 (unique_lift (g·f) d))) in *.
set (gg := pr2 (iscontrpr1 (unique_lift g d'))). cbn in gg.
set (d3 := pr1 (iscontrpr1 (unique_lift g d'))) in *.
assert (XR : ((d'',, ggff) : ∑ r, r -->[g·f] d) = (db,,hh)).
{ apply proofirrelevancecontr. apply (pr2 D). }
assert (XR1 : ((d'',, ggff) : ∑ r, r -->[g·f] d) = (d3 ,,gg;;ff)).
{ apply proofirrelevancecontr. apply (pr2 D). }
assert (XT := maponpaths pr1 XR). cbn in XT.
assert (XT1 := maponpaths pr1 XR1). cbn in XT1.
generalize XR.
generalize XR1; clear XR1.
destruct XT.
generalize gg; clear gg.
destruct XT1.
intros gg XR1 XR0.
apply iscontraprop1.
* apply invproofirrelevance.
intros x x'. apply subtypePath.
{ intro. apply homsets_disp. }
apply disp_mor_unique_disc_fib.
* exists gg.
cbn.
assert (XX := pair_inj (isaset_fiber_discrete_fibration _ _ ) XR1).
assert (YY := pair_inj (isaset_fiber_discrete_fibration _ _ ) XR0).
etrans. apply (!XX). apply YY.
Section Equivalence_disc_fibs_presheaves.
Variable C : category.
Definition precat_of_discrete_fibs_ob_mor : precategory_ob_mor.
Show proof.
Definition precat_of_discrete_fibs_data : precategory_data.
Show proof.
exists precat_of_discrete_fibs_ob_mor.
split.
- intro.
exact (@disp_functor_identity _ _ ).
- intros ? ? ? f g. exact (disp_functor_composite f g ).
split.
- intro.
exact (@disp_functor_identity _ _ ).
- intros ? ? ? f g. exact (disp_functor_composite f g ).
Lemma eq_discrete_fib_mor (F G : precat_of_discrete_fibs_ob_mor)
(a b : F --> G)
(H : ∏ x y, pr1 (pr1 a) x y = pr1 (pr1 b) x y)
: a = b.
Show proof.
apply subtypePath.
{ intro. apply isaprop_disp_functor_axioms. }
use total2_paths_f.
- apply funextsec. intro x.
apply funextsec. intro y.
apply H.
- repeat (apply funextsec; intro).
apply disp_mor_unique_disc_fib.
{ intro. apply isaprop_disp_functor_axioms. }
use total2_paths_f.
- apply funextsec. intro x.
apply funextsec. intro y.
apply H.
- repeat (apply funextsec; intro).
apply disp_mor_unique_disc_fib.
Definition precat_axioms_of_discrete_fibs : is_precategory precat_of_discrete_fibs_data.
Show proof.
Definition precat_of_discrete_fibs : precategory
:= (_ ,, precat_axioms_of_discrete_fibs).
Lemma has_homsets_precat_of_discrete_fibs : has_homsets precat_of_discrete_fibs.
Show proof.
intros f f'.
apply (isofhleveltotal2 2).
- apply (isofhleveltotal2 2).
+ do 2 (apply impred; intro).
apply isaset_fiber_discrete_fibration.
+ intro. do 6 (apply impred; intro).
apply homsets_disp.
- intro. apply isasetaprop. apply isaprop_disp_functor_axioms.
apply (isofhleveltotal2 2).
- apply (isofhleveltotal2 2).
+ do 2 (apply impred; intro).
apply isaset_fiber_discrete_fibration.
+ intro. do 6 (apply impred; intro).
apply homsets_disp.
- intro. apply isasetaprop. apply isaprop_disp_functor_axioms.
Definition Precat_of_discrete_fibs : category
:= ( precat_of_discrete_fibs ,, has_homsets_precat_of_discrete_fibs).
Definition preshv_data_from_disc_fib_ob (D : discrete_fibration C)
: functor_data C^op HSET_univalent_category.
Show proof.
use tpair.
+ intro c. exists (D c). apply isaset_fiber_discrete_fibration.
+ intros c' c f x. cbn in *.
exact (pr1 (iscontrpr1 (unique_lift f x))).
+ intro c. exists (D c). apply isaset_fiber_discrete_fibration.
+ intros c' c f x. cbn in *.
exact (pr1 (iscontrpr1 (unique_lift f x))).
Definition preshv_ax_from_disc_fib_ob (D : discrete_fibration C)
: is_functor (preshv_data_from_disc_fib_ob D).
Show proof.
split.
+ intro c; cbn.
apply funextsec; intro x. simpl.
apply pathsinv0. apply path_to_ctr.
apply id_disp.
+ intros c c' c'' f g. cbn in *.
apply funextsec; intro x.
apply pathsinv0.
apply path_to_ctr.
eapply comp_disp.
* apply (pr2 (iscontrpr1 (unique_lift g _))).
* apply (pr2 (iscontrpr1 (unique_lift f _ ))).
+ intro c; cbn.
apply funextsec; intro x. simpl.
apply pathsinv0. apply path_to_ctr.
apply id_disp.
+ intros c c' c'' f g. cbn in *.
apply funextsec; intro x.
apply pathsinv0.
apply path_to_ctr.
eapply comp_disp.
* apply (pr2 (iscontrpr1 (unique_lift g _))).
* apply (pr2 (iscontrpr1 (unique_lift f _ ))).
Definition preshv_from_disc_fib_ob (D : discrete_fibration C)
: PreShv C := (_ ,, preshv_ax_from_disc_fib_ob D).
Definition foo : functor_data Precat_of_discrete_fibs (PreShv C).
Show proof.
exists preshv_from_disc_fib_ob.
intros D D' a.
use tpair.
- intro c. simpl.
exact (pr1 a c).
- abstract (
intros x y f; cbn in *;
apply funextsec; intro d;
apply path_to_ctr;
apply ♯a;
apply (pr2 (iscontrpr1 (unique_lift f _ )))
).
intros D D' a.
use tpair.
- intro c. simpl.
exact (pr1 a c).
- abstract (
intros x y f; cbn in *;
apply funextsec; intro d;
apply path_to_ctr;
apply ♯a;
apply (pr2 (iscontrpr1 (unique_lift f _ )))
).
Definition bar : is_functor foo.
Show proof.
split.
- intro D. apply nat_trans_eq. { apply has_homsets_HSET. }
intro c . apply idpath.
- intros D E F a b. apply nat_trans_eq. { apply has_homsets_HSET. }
intro c. apply idpath.
- intro D. apply nat_trans_eq. { apply has_homsets_HSET. }
intro c . apply idpath.
- intros D E F a b. apply nat_trans_eq. { apply has_homsets_HSET. }
intro c. apply idpath.
Definition functor_Disc_Fibs_to_preShvs : functor _ _
:= ( _ ,, bar).
Definition disp_cat_from_preshv (D : PreShv C) : disp_cat C.
Show proof.
use tpair.
- use tpair.
+ exists (λ c, pr1hSet (pr1 D c)).
intros x y c d f. exact (functor_on_morphisms (pr1 D) f d = c).
+ split.
* intros; cbn in *; apply (toforallpaths _ _ _ (functor_id D x ) _ ).
* intros ? ? ? ? ? ? ? ? X X0; cbn in *;
etrans; [apply (toforallpaths _ _ _ (functor_comp D g f ) _ ) |];
cbn; etrans; [ apply maponpaths; apply X0 |];
apply X.
- abstract (
repeat use tpair; cbn; intros; try apply setproperty;
apply isasetaprop; apply setproperty
).
- use tpair.
+ exists (λ c, pr1hSet (pr1 D c)).
intros x y c d f. exact (functor_on_morphisms (pr1 D) f d = c).
+ split.
* intros; cbn in *; apply (toforallpaths _ _ _ (functor_id D x ) _ ).
* intros ? ? ? ? ? ? ? ? X X0; cbn in *;
etrans; [apply (toforallpaths _ _ _ (functor_comp D g f ) _ ) |];
cbn; etrans; [ apply maponpaths; apply X0 |];
apply X.
- abstract (
repeat use tpair; cbn; intros; try apply setproperty;
apply isasetaprop; apply setproperty
).
Definition disc_fib_from_preshv (D : PreShv C) : discrete_fibration C.
Show proof.
use tpair.
- apply (disp_cat_from_preshv D).
- cbn.
split.
+ intros c c' f d. simpl.
use unique_exists.
* apply (functor_on_morphisms (pr1 D) f d).
* apply idpath.
* intro. apply setproperty.
* intros. apply pathsinv0. assumption.
+ intro. simpl. apply setproperty.
- apply (disp_cat_from_preshv D).
- cbn.
split.
+ intros c c' f d. simpl.
use unique_exists.
* apply (functor_on_morphisms (pr1 D) f d).
* apply idpath.
* intro. apply setproperty.
* intros. apply pathsinv0. assumption.
+ intro. simpl. apply setproperty.
Definition functor_data_preShv_Disc_fibs
: functor_data (PreShv C) Precat_of_discrete_fibs.
Show proof.
use tpair.
- apply disc_fib_from_preshv.
- intros F G a.
use tpair.
+ use tpair.
* intros c. apply (pr1 a c).
* intros x y X Y f H;
assert (XR := nat_trans_ax a);
apply pathsinv0; etrans; [|apply (toforallpaths _ _ _ (XR _ _ f))];
cbn; apply maponpaths, (!H).
+ cbn. abstract (repeat use tpair; cbn; intros; apply setproperty).
- apply disc_fib_from_preshv.
- intros F G a.
use tpair.
+ use tpair.
* intros c. apply (pr1 a c).
* intros x y X Y f H;
assert (XR := nat_trans_ax a);
apply pathsinv0; etrans; [|apply (toforallpaths _ _ _ (XR _ _ f))];
cbn; apply maponpaths, (!H).
+ cbn. abstract (repeat use tpair; cbn; intros; apply setproperty).
Definition is_functor_functor_data_preShv_Disc_fibs
: is_functor functor_data_preShv_Disc_fibs .
Show proof.
split; unfold functor_idax, functor_compax; intros;
apply eq_discrete_fib_mor; intros; apply idpath.
apply eq_discrete_fib_mor; intros; apply idpath.
Definition functor_preShvs_to_Disc_Fibs : functor _ _
:= ( _ ,, is_functor_functor_data_preShv_Disc_fibs ).
Definition η_disc_fib : nat_trans (functor_identity _ )
(functor_preShvs_to_Disc_Fibs ∙ functor_Disc_Fibs_to_preShvs).
Show proof.
use tpair.
- intro F.
cbn. use tpair.
+ red. cbn. intro c; apply idfun.
+ intros c c' f. cbn in *. apply idpath.
- abstract (
intros F G a;
apply nat_trans_eq; [ apply has_homsets_HSET |];
intro c ; apply idpath
).
- intro F.
cbn. use tpair.
+ red. cbn. intro c; apply idfun.
+ intros c c' f. cbn in *. apply idpath.
- abstract (
intros F G a;
apply nat_trans_eq; [ apply has_homsets_HSET |];
intro c ; apply idpath
).
Definition ε_disc_fib
: nat_trans (functor_Disc_Fibs_to_preShvs ∙ functor_preShvs_to_Disc_Fibs)
(functor_identity _ ).
Show proof.
use tpair.
- intro D.
use tpair.
+ use tpair.
* cbn. intro c; apply idfun.
* cbn. intros c c' x y f H.
set (XR := pr2 (iscontrpr1 (unique_lift f y))). cbn in XR.
apply (transportf (λ t, t -->[f] y) H XR).
+ abstract (split; cbn; intros; apply disp_mor_unique_disc_fib).
- abstract (intros c c' f; apply eq_discrete_fib_mor; intros; apply idpath).
- intro D.
use tpair.
+ use tpair.
* cbn. intro c; apply idfun.
* cbn. intros c c' x y f H.
set (XR := pr2 (iscontrpr1 (unique_lift f y))). cbn in XR.
apply (transportf (λ t, t -->[f] y) H XR).
+ abstract (split; cbn; intros; apply disp_mor_unique_disc_fib).
- abstract (intros c c' f; apply eq_discrete_fib_mor; intros; apply idpath).
Definition ε_inv_disc_fib
: nat_trans (functor_identity _ )
(functor_Disc_Fibs_to_preShvs ∙ functor_preShvs_to_Disc_Fibs).
Show proof.
use tpair.
- intro D.
cbn.
use tpair.
+ use tpair.
* cbn. intro c; apply idfun.
* abstract (
intros c c' x y f H; cbn;
apply pathsinv0; apply path_to_ctr; apply H
).
+ abstract (
split;
[ intros x y; apply isaset_fiber_discrete_fibration |];
intros; apply isaset_fiber_discrete_fibration
).
- abstract (intros c c' f; apply eq_discrete_fib_mor; intros; apply idpath).
- intro D.
cbn.
use tpair.
+ use tpair.
* cbn. intro c; apply idfun.
* abstract (
intros c c' x y f H; cbn;
apply pathsinv0; apply path_to_ctr; apply H
).
+ abstract (
split;
[ intros x y; apply isaset_fiber_discrete_fibration |];
intros; apply isaset_fiber_discrete_fibration
).
- abstract (intros c c' f; apply eq_discrete_fib_mor; intros; apply idpath).
Definition adjunction_data_disc_fib
: adjunction_data (PreShv C) Precat_of_discrete_fibs.
Show proof.
exists functor_preShvs_to_Disc_Fibs.
exists functor_Disc_Fibs_to_preShvs.
exists η_disc_fib.
exact ε_disc_fib.
exists functor_Disc_Fibs_to_preShvs.
exists η_disc_fib.
exact ε_disc_fib.
Lemma forms_equivalence_disc_fib
: forms_equivalence adjunction_data_disc_fib.
Show proof.
split.
- intro F.
apply nat_trafo_z_iso_if_pointwise_z_iso.
intro c. cbn.
set (XR := hset_equiv_is_z_iso _ _ (idweq (pr1 F c : hSet) )).
apply XR.
- intro F.
use (_ ,, (_,,_ )).
+ apply ε_inv_disc_fib.
+ apply eq_discrete_fib_mor.
intros. apply idpath.
+ apply eq_discrete_fib_mor.
intros. apply idpath.
- intro F.
apply nat_trafo_z_iso_if_pointwise_z_iso.
intro c. cbn.
set (XR := hset_equiv_is_z_iso _ _ (idweq (pr1 F c : hSet) )).
apply XR.
- intro F.
use (_ ,, (_,,_ )).
+ apply ε_inv_disc_fib.
+ apply eq_discrete_fib_mor.
intros. apply idpath.
+ apply eq_discrete_fib_mor.
intros. apply idpath.
Definition adj_equivalence_disc_fib : adj_equivalence_of_cats _ :=
adjointification (_ ,, forms_equivalence_disc_fib).
End Equivalence_disc_fibs_presheaves.
End Discrete_Fibrations.
The notion of an opcartesian morphism
Section Opcartesian.
Context {C : category}
{D : disp_cat C}.
Definition is_opcartesian
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: UU
:= ∏ (c₃ : C)
(cc₃ : D c₃)
(g : c₂ --> c₃)
(hh : cc₁ -->[ f · g ] cc₃),
∃! (gg : cc₂ -->[ g ] cc₃),
ff ;; gg = hh.
Section ProjectionsOpcartesian.
Context {c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
{ff : cc₁ -->[ f ] cc₂}
(Hff : is_opcartesian ff)
{c₃ : C}
{cc₃ : D c₃}
(g : c₂ --> c₃)
(hh : cc₁ -->[ f · g ] cc₃).
Definition opcartesian_factorisation
: cc₂ -->[ g ] cc₃
:= pr11 (Hff c₃ cc₃ g hh).
Definition opcartesian_factorisation_commutes
: ff ;; opcartesian_factorisation = hh
:= pr21 (Hff c₃ cc₃ g hh).
Definition opcartesian_factorisation_unique
(gg₁ gg₂ : cc₂ -->[ g ] cc₃)
(H : ff ;; gg₁ = ff ;; gg₂)
: gg₁ = gg₂.
Show proof.
End Opcartesian.
Context {C : category}
{D : disp_cat C}.
Definition is_opcartesian
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: UU
:= ∏ (c₃ : C)
(cc₃ : D c₃)
(g : c₂ --> c₃)
(hh : cc₁ -->[ f · g ] cc₃),
∃! (gg : cc₂ -->[ g ] cc₃),
ff ;; gg = hh.
Section ProjectionsOpcartesian.
Context {c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
{ff : cc₁ -->[ f ] cc₂}
(Hff : is_opcartesian ff)
{c₃ : C}
{cc₃ : D c₃}
(g : c₂ --> c₃)
(hh : cc₁ -->[ f · g ] cc₃).
Definition opcartesian_factorisation
: cc₂ -->[ g ] cc₃
:= pr11 (Hff c₃ cc₃ g hh).
Definition opcartesian_factorisation_commutes
: ff ;; opcartesian_factorisation = hh
:= pr21 (Hff c₃ cc₃ g hh).
Definition opcartesian_factorisation_unique
(gg₁ gg₂ : cc₂ -->[ g ] cc₃)
(H : ff ;; gg₁ = ff ;; gg₂)
: gg₁ = gg₂.
Show proof.
exact (maponpaths
pr1
(proofirrelevance
_
(isapropifcontr
(Hff c₃ cc₃ g (ff ;; gg₁)))
(gg₁ ,, idpath _)
(gg₂ ,, !H))).
End ProjectionsOpcartesian.pr1
(proofirrelevance
_
(isapropifcontr
(Hff c₃ cc₃ g (ff ;; gg₁)))
(gg₁ ,, idpath _)
(gg₂ ,, !H))).
End Opcartesian.
Opcartesian morphism
Definition is_cartesian_weq_is_opcartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: is_cartesian ff ≃ @is_opcartesian _ (op_disp_cat D) _ _ _ _ _ ff.
Show proof.
Definition is_opcartesian_weq_is_cartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: is_opcartesian ff ≃ @is_cartesian _ (op_disp_cat D) _ _ _ _ _ ff.
Show proof.
Definition is_cartesian_to_is_opcartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
{ff : cc₁ -->[ f ] cc₂}
(Hff : @is_cartesian _ (op_disp_cat D) _ _ _ _ _ ff)
: is_opcartesian ff
:= invmap (is_opcartesian_weq_is_cartesian ff) Hff.
Definition isaprop_is_opcartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: isaprop (is_opcartesian ff).
Show proof.
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: is_cartesian ff ≃ @is_opcartesian _ (op_disp_cat D) _ _ _ _ _ ff.
Show proof.
use make_weq.
- exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
- use isweq_iso.
+ exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
+ intro ; apply idpath.
+ intro ; apply idpath.
- exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
- use isweq_iso.
+ exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
+ intro ; apply idpath.
+ intro ; apply idpath.
Definition is_opcartesian_weq_is_cartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: is_opcartesian ff ≃ @is_cartesian _ (op_disp_cat D) _ _ _ _ _ ff.
Show proof.
use make_weq.
- exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
- use isweq_iso.
+ exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
+ intro ; apply idpath.
+ intro ; apply idpath.
- exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
- use isweq_iso.
+ exact (λ Hff c₃ cc₃ g hh, Hff c₃ g cc₃ hh).
+ intro ; apply idpath.
+ intro ; apply idpath.
Definition is_cartesian_to_is_opcartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
{ff : cc₁ -->[ f ] cc₂}
(Hff : @is_cartesian _ (op_disp_cat D) _ _ _ _ _ ff)
: is_opcartesian ff
:= invmap (is_opcartesian_weq_is_cartesian ff) Hff.
Definition isaprop_is_opcartesian
{C : category}
{D : disp_cat C}
{c₁ c₂ : C}
{f : c₁ --> c₂}
{cc₁ : D c₁}
{cc₂ : D c₂}
(ff : cc₁ -->[ f ] cc₂)
: isaprop (is_opcartesian ff).
Show proof.
Opcleavings
Section Opcleaving.
Context {C : category}
(D : disp_cat C).
Definition opcartesian_lift
{c₁ c₂ : C}
(cc₁ : D c₁)
(f : c₁ --> c₂)
: UU
:= ∑ (cc₂ : D c₂) (ff : cc₁ -->[ f ] cc₂), is_opcartesian ff.
Definition ob_of_opcartesian_lift
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: D c₂
:= pr1 ℓ.
Definition mor_of_opcartesian_lift
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: cc₁ -->[ f ] ob_of_opcartesian_lift ℓ
:= pr12 ℓ.
Definition mor_of_opcartesian_lift_is_opcartesian
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: is_opcartesian (mor_of_opcartesian_lift ℓ)
:= pr22 ℓ.
Definition opcleaving
: UU
:= ∏ (c₁ c₂ : C)
(cc₁ : D c₁)
(f : c₁ --> c₂),
opcartesian_lift cc₁ f.
Definition is_opcleaving
: UU
:= ∏ (c₁ c₂ : C)
(cc₁ : D c₁)
(f : c₁ --> c₂),
∥ opcartesian_lift cc₁ f ∥.
End Opcleaving.
Definition opcleaving_ob
{C : category}
{D : disp_cat C}
(HD : opcleaving D)
{c c' : C}
(f : c --> c')
(d : D c)
: D c'
:= ob_of_opcartesian_lift _ (HD c c' d f).
Definition opcleaving_mor
{C : category}
{D : disp_cat C}
(HD : opcleaving D)
{c c' : C}
(f : c --> c')
(d : D c)
: d -->[ f ] opcleaving_ob HD f d
:= mor_of_opcartesian_lift _ (HD c c' d f).
Definition cleaving_weq_opcleaving
{C : category}
(D : disp_cat C)
: cleaving D ≃ @opcleaving _ (op_disp_cat D).
Show proof.
Definition opcleaving_weq_cleaving
{C : category}
(D : disp_cat C)
: opcleaving D ≃ @cleaving _ (op_disp_cat D).
Show proof.
Definition isaprop_opcleaving
{C : univalent_category}
(D : disp_cat C)
(HD : is_univalent_disp D)
: isaprop (opcleaving D).
Show proof.
Context {C : category}
(D : disp_cat C).
Definition opcartesian_lift
{c₁ c₂ : C}
(cc₁ : D c₁)
(f : c₁ --> c₂)
: UU
:= ∑ (cc₂ : D c₂) (ff : cc₁ -->[ f ] cc₂), is_opcartesian ff.
Definition ob_of_opcartesian_lift
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: D c₂
:= pr1 ℓ.
Definition mor_of_opcartesian_lift
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: cc₁ -->[ f ] ob_of_opcartesian_lift ℓ
:= pr12 ℓ.
Definition mor_of_opcartesian_lift_is_opcartesian
{c₁ c₂ : C}
{cc₁ : D c₁}
{f : c₁ --> c₂}
(ℓ : opcartesian_lift cc₁ f)
: is_opcartesian (mor_of_opcartesian_lift ℓ)
:= pr22 ℓ.
Definition opcleaving
: UU
:= ∏ (c₁ c₂ : C)
(cc₁ : D c₁)
(f : c₁ --> c₂),
opcartesian_lift cc₁ f.
Definition is_opcleaving
: UU
:= ∏ (c₁ c₂ : C)
(cc₁ : D c₁)
(f : c₁ --> c₂),
∥ opcartesian_lift cc₁ f ∥.
End Opcleaving.
Definition opcleaving_ob
{C : category}
{D : disp_cat C}
(HD : opcleaving D)
{c c' : C}
(f : c --> c')
(d : D c)
: D c'
:= ob_of_opcartesian_lift _ (HD c c' d f).
Definition opcleaving_mor
{C : category}
{D : disp_cat C}
(HD : opcleaving D)
{c c' : C}
(f : c --> c')
(d : D c)
: d -->[ f ] opcleaving_ob HD f d
:= mor_of_opcartesian_lift _ (HD c c' d f).
Definition cleaving_weq_opcleaving
{C : category}
(D : disp_cat C)
: cleaving D ≃ @opcleaving _ (op_disp_cat D).
Show proof.
use make_weq.
- exact (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
tpair
(fun cc₂ => total2 (fun ff => @is_opcartesian _ _ _ _ _ cc₁ cc₂ ff))
(pr1 ℓ)
(tpair
(@is_opcartesian _ _ _ _ _ cc₁ ℓ) (pr12 ℓ)
(pr1weq (is_cartesian_weq_is_opcartesian ℓ) ℓ))).
- use isweq_iso.
+ refine (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
pr1 ℓ ,, pr12 ℓ ,, _).
exact (invmap (is_cartesian_weq_is_opcartesian _) (pr22 ℓ)).
+ intro ; apply idpath.
+ intro ; apply idpath.
- exact (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
tpair
(fun cc₂ => total2 (fun ff => @is_opcartesian _ _ _ _ _ cc₁ cc₂ ff))
(pr1 ℓ)
(tpair
(@is_opcartesian _ _ _ _ _ cc₁ ℓ) (pr12 ℓ)
(pr1weq (is_cartesian_weq_is_opcartesian ℓ) ℓ))).
- use isweq_iso.
+ refine (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
pr1 ℓ ,, pr12 ℓ ,, _).
exact (invmap (is_cartesian_weq_is_opcartesian _) (pr22 ℓ)).
+ intro ; apply idpath.
+ intro ; apply idpath.
Definition opcleaving_weq_cleaving
{C : category}
(D : disp_cat C)
: opcleaving D ≃ @cleaving _ (op_disp_cat D).
Show proof.
use make_weq.
- exact (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
tpair
(fun d' => total2 (fun ff => @is_cartesian _ _ _ _ _ f d' ff))
(pr1 ℓ)
(tpair
(@is_cartesian _ _ _ _ _ f (pr1 ℓ)) (pr12 ℓ)
(pr1weq
(@is_opcartesian_weq_is_cartesian _ D _ _ _ _ _ (pr12 ℓ))
(pr22 ℓ)))).
- use isweq_iso.
+ refine (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
pr1 ℓ ,, pr12 ℓ ,, _).
exact (invmap (is_opcartesian_weq_is_cartesian _) (pr22 ℓ)).
+ intro ; apply idpath.
+ intro ; apply idpath.
- exact (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
tpair
(fun d' => total2 (fun ff => @is_cartesian _ _ _ _ _ f d' ff))
(pr1 ℓ)
(tpair
(@is_cartesian _ _ _ _ _ f (pr1 ℓ)) (pr12 ℓ)
(pr1weq
(@is_opcartesian_weq_is_cartesian _ D _ _ _ _ _ (pr12 ℓ))
(pr22 ℓ)))).
- use isweq_iso.
+ refine (λ HD c₁ c₂ cc₁ f,
let ℓ := HD c₁ c₂ f cc₁ in
pr1 ℓ ,, pr12 ℓ ,, _).
exact (invmap (is_opcartesian_weq_is_cartesian _) (pr22 ℓ)).
+ intro ; apply idpath.
+ intro ; apply idpath.
Definition isaprop_opcleaving
{C : univalent_category}
(D : disp_cat C)
(HD : is_univalent_disp D)
: isaprop (opcleaving D).
Show proof.
use (isofhlevelweqb
1
(opcleaving_weq_cleaving D)).
use (@isaprop_cleaving (op_unicat C) (op_disp_cat _) _).
apply is_univalent_op_disp_cat.
exact HD.
1
(opcleaving_weq_cleaving D)).
use (@isaprop_cleaving (op_unicat C) (op_disp_cat _) _).
apply is_univalent_op_disp_cat.
exact HD.
Cloven opfibration
Weak opfibration
Definition weak_opfibration
(C : category)
: UU
:= ∑ (D : disp_cat C), is_opcleaving D.
Definition is_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D : disp_cat C₁}
{D' : disp_cat C₂}
(FF : disp_functor F D D')
: UU
:= ∏ (c c' : C₁)
(f : c' --> c)
(d : D c)
(d' : D c')
(ff : d' -->[f] d),
is_opcartesian ff -> is_opcartesian (♯ FF ff).
Proposition isaprop_is_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : disp_functor F D₁ D₂)
: isaprop (is_opcartesian_disp_functor FF).
Show proof.
Definition disp_functor_identity_is_opcartesian_disp_functor
{C : category}
(D : disp_cat C)
: is_opcartesian_disp_functor (disp_functor_identity D).
Show proof.
Definition disp_functor_composite_is_opcartesian_disp_functor
{C₁ C₂ C₃ : category}
{F : C₁ ⟶ C₂}
{G : C₂ ⟶ C₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{D₃ : disp_cat C₃}
{FF : disp_functor F D₁ D₂}
{GG : disp_functor G D₂ D₃}
(HFF : is_opcartesian_disp_functor FF)
(HGG : is_opcartesian_disp_functor GG)
: is_opcartesian_disp_functor (disp_functor_composite FF GG).
Show proof.
Definition disp_functor_over_id_composite_is_opcartesian
{C : category}
{D₁ D₂ D₃ : disp_cat C}
{FF : disp_functor (functor_identity C) D₁ D₂}
{GG : disp_functor (functor_identity C) D₂ D₃}
(HFF : is_opcartesian_disp_functor FF)
(HGG : is_opcartesian_disp_functor GG)
: is_opcartesian_disp_functor (disp_functor_over_id_composite FF GG).
Show proof.
Definition opcartesian_disp_functor
{C₁ C₂ : category}
(F : C₁ ⟶ C₂)
(D₁ : disp_cat C₁)
(D₂ : disp_cat C₂)
: UU
:= ∑ (FF : disp_functor F D₁ D₂), is_opcartesian_disp_functor FF.
Coercion disp_functor_of_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : opcartesian_disp_functor F D₁ D₂)
: disp_functor F D₁ D₂
:= pr1 FF.
Definition opcartesian_disp_functor_is_opcartesian
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : opcartesian_disp_functor F D₁ D₂)
: is_opcartesian_disp_functor FF
:= pr2 FF.
(C : category)
: UU
:= ∑ (D : disp_cat C), is_opcleaving D.
Definition is_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D : disp_cat C₁}
{D' : disp_cat C₂}
(FF : disp_functor F D D')
: UU
:= ∏ (c c' : C₁)
(f : c' --> c)
(d : D c)
(d' : D c')
(ff : d' -->[f] d),
is_opcartesian ff -> is_opcartesian (♯ FF ff).
Proposition isaprop_is_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : disp_functor F D₁ D₂)
: isaprop (is_opcartesian_disp_functor FF).
Show proof.
Definition disp_functor_identity_is_opcartesian_disp_functor
{C : category}
(D : disp_cat C)
: is_opcartesian_disp_functor (disp_functor_identity D).
Show proof.
intros x y f xx yy ff Hff.
exact Hff.
exact Hff.
Definition disp_functor_composite_is_opcartesian_disp_functor
{C₁ C₂ C₃ : category}
{F : C₁ ⟶ C₂}
{G : C₂ ⟶ C₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{D₃ : disp_cat C₃}
{FF : disp_functor F D₁ D₂}
{GG : disp_functor G D₂ D₃}
(HFF : is_opcartesian_disp_functor FF)
(HGG : is_opcartesian_disp_functor GG)
: is_opcartesian_disp_functor (disp_functor_composite FF GG).
Show proof.
intros x y f xx yy ff Hff.
apply HGG.
apply HFF.
exact Hff.
apply HGG.
apply HFF.
exact Hff.
Definition disp_functor_over_id_composite_is_opcartesian
{C : category}
{D₁ D₂ D₃ : disp_cat C}
{FF : disp_functor (functor_identity C) D₁ D₂}
{GG : disp_functor (functor_identity C) D₂ D₃}
(HFF : is_opcartesian_disp_functor FF)
(HGG : is_opcartesian_disp_functor GG)
: is_opcartesian_disp_functor (disp_functor_over_id_composite FF GG).
Show proof.
intros x y f xx yy ff Hff.
apply HGG.
apply HFF.
exact Hff.
apply HGG.
apply HFF.
exact Hff.
Definition opcartesian_disp_functor
{C₁ C₂ : category}
(F : C₁ ⟶ C₂)
(D₁ : disp_cat C₁)
(D₂ : disp_cat C₂)
: UU
:= ∑ (FF : disp_functor F D₁ D₂), is_opcartesian_disp_functor FF.
Coercion disp_functor_of_opcartesian_disp_functor
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : opcartesian_disp_functor F D₁ D₂)
: disp_functor F D₁ D₂
:= pr1 FF.
Definition opcartesian_disp_functor_is_opcartesian
{C₁ C₂ : category}
{F : C₁ ⟶ C₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(FF : opcartesian_disp_functor F D₁ D₂)
: is_opcartesian_disp_functor FF
:= pr2 FF.
Opfibrations are isofibrations
Section IsoCleavingFromOpcleaving.
Context {C : category}
(D : disp_cat C)
(HD : opcleaving D).
Section Lift.
Context {x y : C}
(f : z_iso x y)
(d : D y).
Definition z_iso_cleaving_from_opcleaving_ob
: D x
:= opcleaving_ob HD (inv_from_z_iso f) d.
Let ℓ : d -->[ inv_from_z_iso f ] z_iso_cleaving_from_opcleaving_ob
:= opcleaving_mor HD (inv_from_z_iso f) d.
Let ℓ_opcart : is_opcartesian (pr12 (HD y x d (inv_from_z_iso f)))
:= pr22 (HD _ _ d (inv_from_z_iso f)).
Definition z_iso_cleaving_from_opcleaving_ob_disp_iso_map
: z_iso_cleaving_from_opcleaving_ob -->[ f ] d.
Show proof.
Definition z_iso_cleaving_from_opcleaving_ob_disp_iso
: z_iso_disp f z_iso_cleaving_from_opcleaving_ob d.
Show proof.
Definition iso_cleaving_from_opcleaving
: iso_cleaving D
:= λ x y f d,
z_iso_cleaving_from_opcleaving_ob f d
,,
z_iso_cleaving_from_opcleaving_ob_disp_iso f d.
End IsoCleavingFromOpcleaving.
Section isofibration_from_disp_over_univalent.
Context (C : category)
(Ccat : is_univalent C)
(D : disp_cat C).
Definition iso_cleaving_category : iso_cleaving D.
Show proof.
End isofibration_from_disp_over_univalent.
Context {C : category}
(D : disp_cat C)
(HD : opcleaving D).
Section Lift.
Context {x y : C}
(f : z_iso x y)
(d : D y).
Definition z_iso_cleaving_from_opcleaving_ob
: D x
:= opcleaving_ob HD (inv_from_z_iso f) d.
Let ℓ : d -->[ inv_from_z_iso f ] z_iso_cleaving_from_opcleaving_ob
:= opcleaving_mor HD (inv_from_z_iso f) d.
Let ℓ_opcart : is_opcartesian (pr12 (HD y x d (inv_from_z_iso f)))
:= pr22 (HD _ _ d (inv_from_z_iso f)).
Definition z_iso_cleaving_from_opcleaving_ob_disp_iso_map
: z_iso_cleaving_from_opcleaving_ob -->[ f ] d.
Show proof.
use (opcartesian_factorisation ℓ_opcart).
refine (transportb
(λ z, _ -->[ z ] _)
_
(id_disp d)).
apply z_iso_after_z_iso_inv.
refine (transportb
(λ z, _ -->[ z ] _)
_
(id_disp d)).
apply z_iso_after_z_iso_inv.
Definition z_iso_cleaving_from_opcleaving_ob_disp_iso
: z_iso_disp f z_iso_cleaving_from_opcleaving_ob d.
Show proof.
use make_z_iso_disp.
- exact z_iso_cleaving_from_opcleaving_ob_disp_iso_map.
- simple refine (_ ,, _ ,, _).
+ exact ℓ.
+ abstract
(apply opcartesian_factorisation_commutes).
+ abstract
(apply (opcartesian_factorisation_unique ℓ_opcart) ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite assoc_disp ;
unfold transportb ;
etrans ;
[ apply maponpaths ;
apply maponpaths_2 ;
apply (opcartesian_factorisation_commutes ℓ_opcart)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_postwhisker ;
rewrite id_left_disp, id_right_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths_2 ;
apply homset_property).
End Lift.- exact z_iso_cleaving_from_opcleaving_ob_disp_iso_map.
- simple refine (_ ,, _ ,, _).
+ exact ℓ.
+ abstract
(apply opcartesian_factorisation_commutes).
+ abstract
(apply (opcartesian_factorisation_unique ℓ_opcart) ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite assoc_disp ;
unfold transportb ;
etrans ;
[ apply maponpaths ;
apply maponpaths_2 ;
apply (opcartesian_factorisation_commutes ℓ_opcart)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_postwhisker ;
rewrite id_left_disp, id_right_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths_2 ;
apply homset_property).
Definition iso_cleaving_from_opcleaving
: iso_cleaving D
:= λ x y f d,
z_iso_cleaving_from_opcleaving_ob f d
,,
z_iso_cleaving_from_opcleaving_ob_disp_iso f d.
End IsoCleavingFromOpcleaving.
Section isofibration_from_disp_over_univalent.
Context (C : category)
(Ccat : is_univalent C)
(D : disp_cat C).
Definition iso_cleaving_category : iso_cleaving D.
Show proof.
intros c c' i d.
use tpair.
- exact (transportb D (isotoid _ Ccat i) d).
- generalize i. clear i.
apply forall_isotoid.
{ apply Ccat. }
intro e. induction e.
cbn.
rewrite isotoid_identity_iso.
cbn.
apply identity_z_iso_disp.
use tpair.
- exact (transportb D (isotoid _ Ccat i) d).
- generalize i. clear i.
apply forall_isotoid.
{ apply Ccat. }
intro e. induction e.
cbn.
rewrite isotoid_identity_iso.
cbn.
apply identity_z_iso_disp.
End isofibration_from_disp_over_univalent.
Definition cleaving_ob {C : category} {D : disp_cat C}
(X : cleaving D) {c c' : C} (f : c' --> c) (d : D c)
: D c' := X _ _ f d.
Definition cleaving_mor {C : category} {D : disp_cat C}
(X : cleaving D) {c c' : C} (f : c' --> c) (d : D c)
: cleaving_ob X f d -->[f] d := X _ _ f d.
Definition is_split_id {C : category} {D : disp_cat C}
(X : cleaving D) : UU
:= ∏ c (d : D c),
∑ e : cleaving_ob X (identity _) d = d,
cleaving_mor X (identity _) d =
transportb (λ x, x -->[ _ ] _ ) e (id_disp d).
Definition is_split_comp {C : category} {D : disp_cat C}
(X : cleaving D) : UU
:=
∏ (c c' c'' : C) (f : c' --> c) (g : c'' --> c') (d : D c),
∑ e : cleaving_ob X (g · f) d =
cleaving_ob X g (cleaving_ob X f d),
cleaving_mor X (g · f) d =
transportb (λ x, x -->[ _ ] _ ) e
(cleaving_mor X g (cleaving_ob X f d) ;;
cleaving_mor X f d).
Definition is_split {C : category} {D : disp_cat C}
(X : cleaving D) : UU
:= is_split_id X × is_split_comp X × (∏ c, isaset (D c)).
Lemma is_split_fibration_from_discrete_fibration
{C : category} {D : disp_cat C}
(X : is_discrete_fibration D)
: is_split (fibration_from_discrete_fibration _ (D,,X)).
Show proof.
repeat split.
- intros c d.
cbn.
use tpair.
+ apply pathsinv0.
apply path_to_ctr.
apply id_disp.
+ cbn.
apply (disp_mor_unique_disc_fib _ (D,,X)).
- intros c c' c'' f g d.
cbn.
use tpair.
+ set (XR := unique_lift f d).
set (d' := pr1 (iscontrpr1 XR)).
set (f' := pr2 (iscontrpr1 XR)). cbn in f'.
set (g' := pr2 (iscontrpr1 (unique_lift g d'))).
cbn in g'.
set (gf' := g' ;; f').
match goal with |[ |- ?a = ?b ] =>
assert (X0 : (a,,pr2 (iscontrpr1 (unique_lift (g · f) d))) =
(b,,gf')) end.
{ apply proofirrelevancecontr. apply X. }
apply (maponpaths pr1 X0).
+ apply (disp_mor_unique_disc_fib _ (D,,X)).
- apply isaset_fiber_discrete_fibration.
- intros c d.
cbn.
use tpair.
+ apply pathsinv0.
apply path_to_ctr.
apply id_disp.
+ cbn.
apply (disp_mor_unique_disc_fib _ (D,,X)).
- intros c c' c'' f g d.
cbn.
use tpair.
+ set (XR := unique_lift f d).
set (d' := pr1 (iscontrpr1 XR)).
set (f' := pr2 (iscontrpr1 XR)). cbn in f'.
set (g' := pr2 (iscontrpr1 (unique_lift g d'))).
cbn in g'.
set (gf' := g' ;; f').
match goal with |[ |- ?a = ?b ] =>
assert (X0 : (a,,pr2 (iscontrpr1 (unique_lift (g · f) d))) =
(b,,gf')) end.
{ apply proofirrelevancecontr. apply X. }
apply (maponpaths pr1 X0).
+ apply (disp_mor_unique_disc_fib _ (D,,X)).
- apply isaset_fiber_discrete_fibration.
Some standard cartesian cells
Definition is_cartesian_id_disp
{C : category}
{D : disp_cat C}
{x : C}
(xx : D x)
: is_cartesian (id_disp xx).
Show proof.
Definition is_cartesian_comp_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{z : C}
{zz : D z}
{f : x --> y} {g : y --> z}
{ff : xx -->[ f ] yy} {gg : yy -->[ g ] zz}
(Hff : is_cartesian ff) (Hgg : is_cartesian gg)
: is_cartesian (ff ;; gg)%mor_disp.
Show proof.
Definition is_cartesian_z_iso_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{f : x --> y}
{Hf : is_z_isomorphism f}
{ff : xx -->[ f ] yy}
(Hff : is_z_iso_disp (make_z_iso' f Hf) ff)
: is_cartesian ff.
Show proof.
Definition is_cartesian_transportf
{C : category}
{D : disp_cat C}
{x y : C}
{f f' : x --> y}
(p : f = f')
{xx : D x}
{yy : D y}
{ff : xx -->[ f ] yy}
(Hff : is_cartesian ff)
: is_cartesian (transportf (λ z, _ -->[ z ] _) p ff).
Show proof.
Definition is_cartesian_precomp
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> y}
{g : y --> z}
{h : x --> z}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] yy}
{gg : yy -->[ g ] zz}
{hh : xx -->[ h ] zz}
(p : h = f · g)
(pp : (ff ;; gg = transportf (λ z, _ -->[ z ] _) p hh)%mor_disp)
(Hgg : is_cartesian gg)
(Hhh : is_cartesian hh)
: is_cartesian ff.
Show proof.
Definition z_iso_disp_to_is_cartesian
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> z}
{g : y --> z}
{h : y --> x}
(Hh : is_z_isomorphism h)
{p : h · f = g}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] zz}
{gg : yy -->[ g ] zz}
{hh : yy -->[ h ] xx}
(Hff : is_cartesian ff)
(Hhh : is_z_iso_disp (make_z_iso' h Hh) hh)
(pp : (hh ;; ff = transportb _ p gg)%mor_disp)
: is_cartesian gg.
Show proof.
Definition is_opcartesian_id_disp
{C : category}
{D : disp_cat C}
{x : C}
(xx : D x)
: is_opcartesian (id_disp xx).
Show proof.
Definition is_opcartesian_comp_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{z : C}
{zz : D z}
{f : x --> y} {g : y --> z}
{ff : xx -->[ f ] yy} {gg : yy -->[ g ] zz}
(Hff : is_opcartesian ff) (Hgg : is_opcartesian gg)
: is_opcartesian (ff ;; gg)%mor_disp.
Show proof.
Definition is_opcartesian_postcomp
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> y}
{g : y --> z}
{h : x --> z}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] yy}
{gg : yy -->[ g ] zz}
{hh : xx -->[ h ] zz}
(p : h = f · g)
(pp : (ff ;; gg = transportf (λ z, _ -->[ z ] _) p hh)%mor_disp)
(Hff : is_opcartesian ff)
(Hhh : is_opcartesian hh)
: is_opcartesian gg.
Show proof.
Definition is_opcartesian_z_iso_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{f : x --> y}
{Hf : is_z_isomorphism f}
{ff : xx -->[ f ] yy}
(Hff : is_z_iso_disp (make_z_iso' f Hf) ff)
: is_opcartesian ff.
Show proof.
Definition is_opcartesian_transportf
{C : category}
{D : disp_cat C}
{x y : C}
{f f' : x --> y}
(p : f = f')
{xx : D x}
{yy : D y}
{ff : xx -->[ f ] yy}
(Hff : is_opcartesian ff)
: is_opcartesian (transportf (λ z, _ -->[ z ] _) p ff).
Show proof.
{C : category}
{D : disp_cat C}
{x : C}
(xx : D x)
: is_cartesian (id_disp xx).
Show proof.
intros z g zz hh.
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros f₁ f₂ ;
use subtypePath ; [ intro ; intros ; apply D | ] ;
refine (id_right_disp_var _ @ _ @ !(id_right_disp_var _)) ;
rewrite (pr2 f₁), (pr2 f₂) ;
apply idpath).
- use tpair.
+ exact (transportf _ (id_right _) hh).
+ abstract
(simpl ;
rewrite id_right_disp ;
unfold transportb ;
rewrite transport_f_f ;
rewrite pathsinv0r ;
apply idpath).
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros f₁ f₂ ;
use subtypePath ; [ intro ; intros ; apply D | ] ;
refine (id_right_disp_var _ @ _ @ !(id_right_disp_var _)) ;
rewrite (pr2 f₁), (pr2 f₂) ;
apply idpath).
- use tpair.
+ exact (transportf _ (id_right _) hh).
+ abstract
(simpl ;
rewrite id_right_disp ;
unfold transportb ;
rewrite transport_f_f ;
rewrite pathsinv0r ;
apply idpath).
Definition is_cartesian_comp_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{z : C}
{zz : D z}
{f : x --> y} {g : y --> z}
{ff : xx -->[ f ] yy} {gg : yy -->[ g ] zz}
(Hff : is_cartesian ff) (Hgg : is_cartesian gg)
: is_cartesian (ff ;; gg)%mor_disp.
Show proof.
intros w h ww hh'.
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros f₁ f₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hff) ;
use (cartesian_factorisation_unique Hgg) ;
rewrite !assoc_disp_var ;
rewrite (pr2 f₁), (pr2 f₂) ;
apply idpath).
- simple refine (_ ,, _).
+ exact (cartesian_factorisation
Hff
h
(cartesian_factorisation
Hgg
(h · f)
(transportf
(λ z, _ -->[ z ] _)
(assoc _ _ _)
hh'))).
+ abstract
(simpl ;
rewrite assoc_disp ;
rewrite !cartesian_factorisation_commutes ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros f₁ f₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hff) ;
use (cartesian_factorisation_unique Hgg) ;
rewrite !assoc_disp_var ;
rewrite (pr2 f₁), (pr2 f₂) ;
apply idpath).
- simple refine (_ ,, _).
+ exact (cartesian_factorisation
Hff
h
(cartesian_factorisation
Hgg
(h · f)
(transportf
(λ z, _ -->[ z ] _)
(assoc _ _ _)
hh'))).
+ abstract
(simpl ;
rewrite assoc_disp ;
rewrite !cartesian_factorisation_commutes ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
Definition is_cartesian_z_iso_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{f : x --> y}
{Hf : is_z_isomorphism f}
{ff : xx -->[ f ] yy}
(Hff : is_z_iso_disp (make_z_iso' f Hf) ff)
: is_cartesian ff.
Show proof.
intros z g zz gf.
use iscontraprop1.
- abstract
(apply invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
pose (pr2 φ₁ @ !(pr2 φ₂)) as r ;
refine (id_right_disp_var _ @ _ @ !(id_right_disp_var _)) ;
pose (transportf_transpose_left (inv_mor_after_z_iso_disp Hff)) as r' ;
rewrite <- !r' ; clear r' ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !assoc_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths ;
apply maponpaths_2 ;
exact r).
- simple refine (_ ,, _).
+ refine (transportf
(λ z, _ -->[ z ] _)
_
(gf ;; inv_mor_disp_from_z_iso Hff)%mor_disp).
abstract
(rewrite assoc' ;
refine (_ @ id_right _) ;
apply maponpaths ;
apply (z_iso_inv_after_z_iso (make_z_iso' f Hf))).
+ abstract
(simpl ;
rewrite mor_disp_transportf_postwhisker ;
rewrite assoc_disp_var ;
rewrite transport_f_f ;
etrans ;
[ do 2 apply maponpaths ;
apply (z_iso_disp_after_inv_mor Hff)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite transport_f_f ;
rewrite id_right_disp ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property ;
rewrite disp_id_right).
use iscontraprop1.
- abstract
(apply invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
pose (pr2 φ₁ @ !(pr2 φ₂)) as r ;
refine (id_right_disp_var _ @ _ @ !(id_right_disp_var _)) ;
pose (transportf_transpose_left (inv_mor_after_z_iso_disp Hff)) as r' ;
rewrite <- !r' ; clear r' ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !assoc_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths ;
apply maponpaths_2 ;
exact r).
- simple refine (_ ,, _).
+ refine (transportf
(λ z, _ -->[ z ] _)
_
(gf ;; inv_mor_disp_from_z_iso Hff)%mor_disp).
abstract
(rewrite assoc' ;
refine (_ @ id_right _) ;
apply maponpaths ;
apply (z_iso_inv_after_z_iso (make_z_iso' f Hf))).
+ abstract
(simpl ;
rewrite mor_disp_transportf_postwhisker ;
rewrite assoc_disp_var ;
rewrite transport_f_f ;
etrans ;
[ do 2 apply maponpaths ;
apply (z_iso_disp_after_inv_mor Hff)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite transport_f_f ;
rewrite id_right_disp ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property ;
rewrite disp_id_right).
Definition is_cartesian_transportf
{C : category}
{D : disp_cat C}
{x y : C}
{f f' : x --> y}
(p : f = f')
{xx : D x}
{yy : D y}
{ff : xx -->[ f ] yy}
(Hff : is_cartesian ff)
: is_cartesian (transportf (λ z, _ -->[ z ] _) p ff).
Show proof.
intros c g cc gg.
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hff) ;
pose (p₁ := pr2 φ₁) ;
pose (p₂ := pr2 φ₂) ;
cbn in p₁, p₂ ;
rewrite mor_disp_transportf_prewhisker in p₁ ;
rewrite mor_disp_transportf_prewhisker in p₂ ;
pose (transportb_transpose_right p₁) as r₁ ;
pose (transportb_transpose_right p₂) as r₂ ;
exact (r₁ @ !r₂)).
- simple refine (_ ,, _).
+ exact (cartesian_factorisation
Hff
g
(transportb
(λ z, _ -->[ z ] _)
(maponpaths (λ z, g · z) p)
gg)).
+ abstract
(cbn ;
rewrite mor_disp_transportf_prewhisker ;
rewrite cartesian_factorisation_commutes ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hff) ;
pose (p₁ := pr2 φ₁) ;
pose (p₂ := pr2 φ₂) ;
cbn in p₁, p₂ ;
rewrite mor_disp_transportf_prewhisker in p₁ ;
rewrite mor_disp_transportf_prewhisker in p₂ ;
pose (transportb_transpose_right p₁) as r₁ ;
pose (transportb_transpose_right p₂) as r₂ ;
exact (r₁ @ !r₂)).
- simple refine (_ ,, _).
+ exact (cartesian_factorisation
Hff
g
(transportb
(λ z, _ -->[ z ] _)
(maponpaths (λ z, g · z) p)
gg)).
+ abstract
(cbn ;
rewrite mor_disp_transportf_prewhisker ;
rewrite cartesian_factorisation_commutes ;
unfold transportb ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
Definition is_cartesian_precomp
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> y}
{g : y --> z}
{h : x --> z}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] yy}
{gg : yy -->[ g ] zz}
{hh : xx -->[ h ] zz}
(p : h = f · g)
(pp : (ff ;; gg = transportf (λ z, _ -->[ z ] _) p hh)%mor_disp)
(Hgg : is_cartesian gg)
(Hhh : is_cartesian hh)
: is_cartesian ff.
Show proof.
intros w φ ww φφ.
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros ψ₁ ψ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hhh) ;
rewrite <- (transportb_transpose_left pp) ;
unfold transportb ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !assoc_disp ;
rewrite (pr2 ψ₁), (pr2 ψ₂) ;
apply idpath).
- simple refine (_ ,, _).
+ refine (cartesian_factorisation
Hhh
φ
(transportf (λ z, _ -->[ z ] _) _ (φφ ;; gg)%mor_disp)).
abstract
(rewrite p ;
rewrite assoc ;
apply idpath).
+ abstract
(simpl ;
use (cartesian_factorisation_unique Hgg) ;
rewrite assoc_disp_var ;
rewrite pp ;
rewrite mor_disp_transportf_prewhisker ;
rewrite transport_f_f ;
rewrite cartesian_factorisation_commutes ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros ψ₁ ψ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (cartesian_factorisation_unique Hhh) ;
rewrite <- (transportb_transpose_left pp) ;
unfold transportb ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !assoc_disp ;
rewrite (pr2 ψ₁), (pr2 ψ₂) ;
apply idpath).
- simple refine (_ ,, _).
+ refine (cartesian_factorisation
Hhh
φ
(transportf (λ z, _ -->[ z ] _) _ (φφ ;; gg)%mor_disp)).
abstract
(rewrite p ;
rewrite assoc ;
apply idpath).
+ abstract
(simpl ;
use (cartesian_factorisation_unique Hgg) ;
rewrite assoc_disp_var ;
rewrite pp ;
rewrite mor_disp_transportf_prewhisker ;
rewrite transport_f_f ;
rewrite cartesian_factorisation_commutes ;
rewrite transport_f_f ;
apply transportf_set ;
apply homset_property).
Definition z_iso_disp_to_is_cartesian
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> z}
{g : y --> z}
{h : y --> x}
(Hh : is_z_isomorphism h)
{p : h · f = g}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] zz}
{gg : yy -->[ g ] zz}
{hh : yy -->[ h ] xx}
(Hff : is_cartesian ff)
(Hhh : is_z_iso_disp (make_z_iso' h Hh) hh)
(pp : (hh ;; ff = transportb _ p gg)%mor_disp)
: is_cartesian gg.
Show proof.
intros q k qq kg.
assert (f = inv_from_z_iso (make_z_iso' h Hh) · g) as r.
{
abstract
(refine (!_) ;
use z_iso_inv_on_right ;
exact (!p)).
}
assert (transportf (λ z, _ -->[ z ] _) r ff
=
inv_mor_disp_from_z_iso Hhh ;; gg)%mor_disp as rr.
{
abstract
(rewrite <- (transportb_transpose_left pp) ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite assoc_disp ;
refine (!_) ;
etrans ;
[ do 2 apply maponpaths ;
apply maponpaths_2 ;
exact (z_iso_disp_after_inv_mor Hhh)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_postwhisker ;
rewrite id_left_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths_2 ;
apply homset_property).
}
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (postcomp_with_z_iso_disp_is_inj Hh (idpath _) Hhh) ; cbn ;
use (cartesian_factorisation_unique Hff) ;
rewrite !assoc_disp_var ;
rewrite pp ;
unfold transportb ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !transport_f_f ;
apply maponpaths ;
exact (pr2 φ₁ @ !(pr2 φ₂))).
- simple refine (_ ,, _).
+ refine (transportf
(λ z, _ -->[ z ] _)
_
(cartesian_factorisation
Hff
(k · h)
(transportf
(λ z, _ -->[ z ] _)
_
kg)
;; inv_mor_disp_from_z_iso Hhh)%mor_disp).
* abstract
(rewrite assoc' ;
etrans ; [ apply maponpaths ; apply (z_iso_inv_after_z_iso (make_z_iso' h Hh)) | ] ;
apply id_right).
* abstract
(rewrite assoc' ;
rewrite p ;
apply idpath).
+ abstract
(simpl ;
rewrite mor_disp_transportf_postwhisker ;
rewrite assoc_disp_var ;
etrans ; [ do 3 apply maponpaths ; exact (!rr) | ] ;
rewrite transport_f_f ;
rewrite mor_disp_transportf_prewhisker ;
rewrite cartesian_factorisation_commutes ;
rewrite !transport_f_f ;
apply transportf_set ;
apply homset_property).
assert (f = inv_from_z_iso (make_z_iso' h Hh) · g) as r.
{
abstract
(refine (!_) ;
use z_iso_inv_on_right ;
exact (!p)).
}
assert (transportf (λ z, _ -->[ z ] _) r ff
=
inv_mor_disp_from_z_iso Hhh ;; gg)%mor_disp as rr.
{
abstract
(rewrite <- (transportb_transpose_left pp) ;
unfold transportb ;
rewrite mor_disp_transportf_prewhisker ;
rewrite assoc_disp ;
refine (!_) ;
etrans ;
[ do 2 apply maponpaths ;
apply maponpaths_2 ;
exact (z_iso_disp_after_inv_mor Hhh)
| ] ;
unfold transportb ;
rewrite mor_disp_transportf_postwhisker ;
rewrite id_left_disp ;
unfold transportb ;
rewrite !transport_f_f ;
apply maponpaths_2 ;
apply homset_property).
}
use iscontraprop1.
- abstract
(use invproofirrelevance ;
intros φ₁ φ₂ ;
use subtypePath ; [ intro ; apply D | ] ;
use (postcomp_with_z_iso_disp_is_inj Hh (idpath _) Hhh) ; cbn ;
use (cartesian_factorisation_unique Hff) ;
rewrite !assoc_disp_var ;
rewrite pp ;
unfold transportb ;
rewrite !mor_disp_transportf_prewhisker ;
rewrite !transport_f_f ;
apply maponpaths ;
exact (pr2 φ₁ @ !(pr2 φ₂))).
- simple refine (_ ,, _).
+ refine (transportf
(λ z, _ -->[ z ] _)
_
(cartesian_factorisation
Hff
(k · h)
(transportf
(λ z, _ -->[ z ] _)
_
kg)
;; inv_mor_disp_from_z_iso Hhh)%mor_disp).
* abstract
(rewrite assoc' ;
etrans ; [ apply maponpaths ; apply (z_iso_inv_after_z_iso (make_z_iso' h Hh)) | ] ;
apply id_right).
* abstract
(rewrite assoc' ;
rewrite p ;
apply idpath).
+ abstract
(simpl ;
rewrite mor_disp_transportf_postwhisker ;
rewrite assoc_disp_var ;
etrans ; [ do 3 apply maponpaths ; exact (!rr) | ] ;
rewrite transport_f_f ;
rewrite mor_disp_transportf_prewhisker ;
rewrite cartesian_factorisation_commutes ;
rewrite !transport_f_f ;
apply transportf_set ;
apply homset_property).
Definition is_opcartesian_id_disp
{C : category}
{D : disp_cat C}
{x : C}
(xx : D x)
: is_opcartesian (id_disp xx).
Show proof.
Definition is_opcartesian_comp_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{z : C}
{zz : D z}
{f : x --> y} {g : y --> z}
{ff : xx -->[ f ] yy} {gg : yy -->[ g ] zz}
(Hff : is_opcartesian ff) (Hgg : is_opcartesian gg)
: is_opcartesian (ff ;; gg)%mor_disp.
Show proof.
apply is_cartesian_to_is_opcartesian.
use (@is_cartesian_comp_disp _ (op_disp_cat D)).
- apply is_opcartesian_weq_is_cartesian.
exact Hgg.
- apply is_opcartesian_weq_is_cartesian.
exact Hff.
use (@is_cartesian_comp_disp _ (op_disp_cat D)).
- apply is_opcartesian_weq_is_cartesian.
exact Hgg.
- apply is_opcartesian_weq_is_cartesian.
exact Hff.
Definition is_opcartesian_postcomp
{C : category}
{D : disp_cat C}
{x y z : C}
{f : x --> y}
{g : y --> z}
{h : x --> z}
{xx : D x}
{yy : D y}
{zz : D z}
{ff : xx -->[ f ] yy}
{gg : yy -->[ g ] zz}
{hh : xx -->[ h ] zz}
(p : h = f · g)
(pp : (ff ;; gg = transportf (λ z, _ -->[ z ] _) p hh)%mor_disp)
(Hff : is_opcartesian ff)
(Hhh : is_opcartesian hh)
: is_opcartesian gg.
Show proof.
apply is_cartesian_to_is_opcartesian.
use (@is_cartesian_precomp _ (op_disp_cat D) _ _ _ g f h zz yy xx gg ff hh p pp).
- apply is_opcartesian_weq_is_cartesian.
exact Hff.
- apply is_opcartesian_weq_is_cartesian.
exact Hhh.
use (@is_cartesian_precomp _ (op_disp_cat D) _ _ _ g f h zz yy xx gg ff hh p pp).
- apply is_opcartesian_weq_is_cartesian.
exact Hff.
- apply is_opcartesian_weq_is_cartesian.
exact Hhh.
Definition is_opcartesian_z_iso_disp
{C : category}
{D : disp_cat C}
{x : C}
{xx : D x}
{y : C}
{yy : D y}
{f : x --> y}
{Hf : is_z_isomorphism f}
{ff : xx -->[ f ] yy}
(Hff : is_z_iso_disp (make_z_iso' f Hf) ff)
: is_opcartesian ff.
Show proof.
apply is_cartesian_to_is_opcartesian.
use (@is_cartesian_z_iso_disp _ (op_disp_cat D) _ _ _ _ _ _ ff).
- exact (pr2 (@opp_z_iso C _ _ (make_z_iso' f Hf))).
- use (@to_z_iso_disp_op_disp_cat C D y x (make_z_iso' f Hf) yy xx ff).
exact Hff.
use (@is_cartesian_z_iso_disp _ (op_disp_cat D) _ _ _ _ _ _ ff).
- exact (pr2 (@opp_z_iso C _ _ (make_z_iso' f Hf))).
- use (@to_z_iso_disp_op_disp_cat C D y x (make_z_iso' f Hf) yy xx ff).
exact Hff.
Definition is_opcartesian_transportf
{C : category}
{D : disp_cat C}
{x y : C}
{f f' : x --> y}
(p : f = f')
{xx : D x}
{yy : D y}
{ff : xx -->[ f ] yy}
(Hff : is_opcartesian ff)
: is_opcartesian (transportf (λ z, _ -->[ z ] _) p ff).
Show proof.
apply is_cartesian_to_is_opcartesian.
apply (@is_cartesian_transportf _ (op_disp_cat D)).
apply is_opcartesian_weq_is_cartesian.
exact Hff.
apply (@is_cartesian_transportf _ (op_disp_cat D)).
apply is_opcartesian_weq_is_cartesian.
exact Hff.
Cartesian factorisation of disp nat trans and functor
Section CartesianFactorisationDispNatTrans.
Context {C₁ C₂ : category}
{F₁ F₂ F₃ : C₁ ⟶ C₂}
{α : F₂ ⟹ F₃}
{β : F₁ ⟹ F₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{FF₁ : disp_functor F₁ D₁ D₂}
{FF₂ : disp_functor F₂ D₁ D₂}
{FF₃ : disp_functor F₃ D₁ D₂}
(αα : disp_nat_trans α FF₂ FF₃)
(ββ : disp_nat_trans (nat_trans_comp _ _ _ β α) FF₁ FF₃)
(Hαα : ∏ (x : C₁) (xx : D₁ x), is_cartesian (αα x xx)).
Definition cartesian_factorisation_disp_nat_trans_data
: disp_nat_trans_data β FF₁ FF₂
:= λ x xx, cartesian_factorisation (Hαα x xx) (β x) (ββ x xx).
Definition cartesian_factorisation_disp_nat_trans_axioms
: disp_nat_trans_axioms cartesian_factorisation_disp_nat_trans_data.
Show proof.
Definition cartesian_factorisation_disp_nat_trans
: disp_nat_trans β FF₁ FF₂.
Show proof.
Section CartesianFactorisationDispFunctor.
Context {C₁ C₂ : category}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(HD₁ : cleaving D₂)
{F G : C₁ ⟶ C₂}
(GG : disp_functor G D₁ D₂)
(α : F ⟹ G).
Definition cartesian_factorisation_disp_functor_data
: disp_functor_data F D₁ D₂.
Show proof.
Definition cartesian_factorisation_disp_functor_axioms
: disp_functor_axioms cartesian_factorisation_disp_functor_data.
Show proof.
Definition cartesian_factorisation_disp_functor
: disp_functor F D₁ D₂.
Show proof.
Definition cartesian_factorisation_disp_functor_is_cartesian
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor cartesian_factorisation_disp_functor.
Show proof.
Definition cartesian_factorisation_disp_functor_cell_data
: disp_nat_trans_data α cartesian_factorisation_disp_functor_data GG
:= λ x xx, pr12 (HD₁ (G x) (F x) (α x) (GG x xx)).
Definition cartesian_factorisation_disp_functor_cell_axioms
: disp_nat_trans_axioms cartesian_factorisation_disp_functor_cell_data.
Show proof.
Definition cartesian_factorisation_disp_functor_cell
: disp_nat_trans
α
cartesian_factorisation_disp_functor_data
GG.
Show proof.
Definition cartesian_factorisation_disp_functor_cell_is_cartesian
{x : C₁}
(xx : D₁ x)
: is_cartesian (cartesian_factorisation_disp_functor_cell x xx).
Show proof.
End CartesianFactorisationDispFunctor.
Context {C₁ C₂ : category}
{F₁ F₂ F₃ : C₁ ⟶ C₂}
{α : F₂ ⟹ F₃}
{β : F₁ ⟹ F₂}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{FF₁ : disp_functor F₁ D₁ D₂}
{FF₂ : disp_functor F₂ D₁ D₂}
{FF₃ : disp_functor F₃ D₁ D₂}
(αα : disp_nat_trans α FF₂ FF₃)
(ββ : disp_nat_trans (nat_trans_comp _ _ _ β α) FF₁ FF₃)
(Hαα : ∏ (x : C₁) (xx : D₁ x), is_cartesian (αα x xx)).
Definition cartesian_factorisation_disp_nat_trans_data
: disp_nat_trans_data β FF₁ FF₂
:= λ x xx, cartesian_factorisation (Hαα x xx) (β x) (ββ x xx).
Definition cartesian_factorisation_disp_nat_trans_axioms
: disp_nat_trans_axioms cartesian_factorisation_disp_nat_trans_data.
Show proof.
intros x y f xx yy ff ; cbn in *.
unfold cartesian_factorisation_disp_nat_trans_data.
use (cartesian_factorisation_unique (Hαα y yy)).
rewrite assoc_disp_var.
rewrite cartesian_factorisation_commutes.
refine (maponpaths _ (disp_nat_trans_ax ββ ff) @ _).
unfold transportb.
rewrite !transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
refine (!_).
etrans.
{
do 2 apply maponpaths.
exact (disp_nat_trans_ax αα ff).
}
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
apply maponpaths_2.
apply homset_property.
unfold cartesian_factorisation_disp_nat_trans_data.
use (cartesian_factorisation_unique (Hαα y yy)).
rewrite assoc_disp_var.
rewrite cartesian_factorisation_commutes.
refine (maponpaths _ (disp_nat_trans_ax ββ ff) @ _).
unfold transportb.
rewrite !transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
refine (!_).
etrans.
{
do 2 apply maponpaths.
exact (disp_nat_trans_ax αα ff).
}
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
apply maponpaths_2.
apply homset_property.
Definition cartesian_factorisation_disp_nat_trans
: disp_nat_trans β FF₁ FF₂.
Show proof.
simple refine (_ ,, _).
- exact cartesian_factorisation_disp_nat_trans_data.
- exact cartesian_factorisation_disp_nat_trans_axioms.
End CartesianFactorisationDispNatTrans.- exact cartesian_factorisation_disp_nat_trans_data.
- exact cartesian_factorisation_disp_nat_trans_axioms.
Section CartesianFactorisationDispFunctor.
Context {C₁ C₂ : category}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(HD₁ : cleaving D₂)
{F G : C₁ ⟶ C₂}
(GG : disp_functor G D₁ D₂)
(α : F ⟹ G).
Definition cartesian_factorisation_disp_functor_data
: disp_functor_data F D₁ D₂.
Show proof.
simple refine (_ ,, _).
- exact (λ x xx, pr1 (HD₁ (G x) (F x) (α x) (GG x xx))).
- exact (λ x y xx yy f ff,
cartesian_factorisation
(pr22 (HD₁ (G y) (F y) (α y) (GG y yy)))
_
(transportb
(λ z, _ -->[ z ] _)
(nat_trans_ax α _ _ f)
(pr12 (HD₁ (G x) (F x) (α x) (GG x xx)) ;; ♯ GG ff))).
- exact (λ x xx, pr1 (HD₁ (G x) (F x) (α x) (GG x xx))).
- exact (λ x y xx yy f ff,
cartesian_factorisation
(pr22 (HD₁ (G y) (F y) (α y) (GG y yy)))
_
(transportb
(λ z, _ -->[ z ] _)
(nat_trans_ax α _ _ f)
(pr12 (HD₁ (G x) (F x) (α x) (GG x xx)) ;; ♯ GG ff))).
Definition cartesian_factorisation_disp_functor_axioms
: disp_functor_axioms cartesian_factorisation_disp_functor_data.
Show proof.
repeat split.
- intros x xx ; cbn.
use (cartesian_factorisation_unique
(pr22 (HD₁ (G x) (F x) (α x) (GG x xx)))).
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_id.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x y z xx yy zz f g ff hh ; cbn.
use (cartesian_factorisation_unique
(pr22 (HD₁ (G z) (F z) (α z) (GG z zz)))).
unfold transportb.
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite !assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x xx ; cbn.
use (cartesian_factorisation_unique
(pr22 (HD₁ (G x) (F x) (α x) (GG x xx)))).
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_id.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x y z xx yy zz f g ff hh ; cbn.
use (cartesian_factorisation_unique
(pr22 (HD₁ (G z) (F z) (α z) (GG z zz)))).
unfold transportb.
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite !assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition cartesian_factorisation_disp_functor
: disp_functor F D₁ D₂.
Show proof.
simple refine (_ ,, _).
- exact cartesian_factorisation_disp_functor_data.
- exact cartesian_factorisation_disp_functor_axioms.
- exact cartesian_factorisation_disp_functor_data.
- exact cartesian_factorisation_disp_functor_axioms.
Definition cartesian_factorisation_disp_functor_is_cartesian
(HGG : is_cartesian_disp_functor GG)
: is_cartesian_disp_functor cartesian_factorisation_disp_functor.
Show proof.
intros x y f xx yy ff Hff ; cbn.
pose (HGff := HGG _ _ _ _ _ _ Hff).
refine (is_cartesian_precomp
(idpath _)
_
(pr22 (HD₁ (G x) (F x) (α x) (GG x xx)))
(is_cartesian_transportf
(!(nat_trans_ax α _ _ f))
(is_cartesian_comp_disp
(pr22 (HD₁ (G y) (F y) (α y) (GG y yy)))
HGff))).
rewrite cartesian_factorisation_commutes.
apply idpath.
pose (HGff := HGG _ _ _ _ _ _ Hff).
refine (is_cartesian_precomp
(idpath _)
_
(pr22 (HD₁ (G x) (F x) (α x) (GG x xx)))
(is_cartesian_transportf
(!(nat_trans_ax α _ _ f))
(is_cartesian_comp_disp
(pr22 (HD₁ (G y) (F y) (α y) (GG y yy)))
HGff))).
rewrite cartesian_factorisation_commutes.
apply idpath.
Definition cartesian_factorisation_disp_functor_cell_data
: disp_nat_trans_data α cartesian_factorisation_disp_functor_data GG
:= λ x xx, pr12 (HD₁ (G x) (F x) (α x) (GG x xx)).
Definition cartesian_factorisation_disp_functor_cell_axioms
: disp_nat_trans_axioms cartesian_factorisation_disp_functor_cell_data.
Show proof.
intros x y f xx yy ff ; cbn ; unfold cartesian_factorisation_disp_functor_cell_data.
unfold transportb.
rewrite cartesian_factorisation_commutes.
apply idpath.
unfold transportb.
rewrite cartesian_factorisation_commutes.
apply idpath.
Definition cartesian_factorisation_disp_functor_cell
: disp_nat_trans
α
cartesian_factorisation_disp_functor_data
GG.
Show proof.
simple refine (_ ,, _).
- exact cartesian_factorisation_disp_functor_cell_data.
- exact cartesian_factorisation_disp_functor_cell_axioms.
- exact cartesian_factorisation_disp_functor_cell_data.
- exact cartesian_factorisation_disp_functor_cell_axioms.
Definition cartesian_factorisation_disp_functor_cell_is_cartesian
{x : C₁}
(xx : D₁ x)
: is_cartesian (cartesian_factorisation_disp_functor_cell x xx).
Show proof.
End CartesianFactorisationDispFunctor.
Cartesian factorisation of disp nat trans and functor
Section OpCartesianFactorisationDispNatTrans.
Context {C₁ C₂ : category}
{F₁ F₂ F₃ : C₁ ⟶ C₂}
{α : F₁ ⟹ F₂}
{β : F₂ ⟹ F₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{FF₁ : disp_functor F₁ D₁ D₂}
{FF₂ : disp_functor F₂ D₁ D₂}
{FF₃ : disp_functor F₃ D₁ D₂}
(αα : disp_nat_trans α FF₁ FF₂)
(ββ : disp_nat_trans (nat_trans_comp _ _ _ α β) FF₁ FF₃)
(Hαα : ∏ (x : C₁) (xx : D₁ x), is_opcartesian (αα x xx)).
Definition opcartesian_factorisation_disp_nat_trans_data
: disp_nat_trans_data β FF₂ FF₃
:= λ x xx, opcartesian_factorisation (Hαα x xx) (β x) (ββ x xx).
Definition opcartesian_factorisation_disp_nat_trans_axioms
: disp_nat_trans_axioms opcartesian_factorisation_disp_nat_trans_data.
Show proof.
Definition opcartesian_factorisation_disp_nat_trans
: disp_nat_trans β FF₂ FF₃.
Show proof.
Section OpCartesianFactorisationDispFunctor.
Context {C₁ C₂ : category}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(HD₁ : opcleaving D₂)
{F G : C₁ ⟶ C₂}
(FF : disp_functor F D₁ D₂)
(α : F ⟹ G).
Definition opcartesian_factorisation_disp_functor_data
: disp_functor_data G D₁ D₂.
Show proof.
Definition opcartesian_factorisation_disp_functor_axioms
: disp_functor_axioms opcartesian_factorisation_disp_functor_data.
Show proof.
Definition opcartesian_factorisation_disp_functor
: disp_functor G D₁ D₂.
Show proof.
Definition opcartesian_factorisation_disp_functor_is_opcartesian
(HFF : is_opcartesian_disp_functor FF)
: is_opcartesian_disp_functor opcartesian_factorisation_disp_functor.
Show proof.
Definition opcartesian_factorisation_disp_functor_cell_data
: disp_nat_trans_data α FF opcartesian_factorisation_disp_functor_data
:= λ x xx, pr12 (HD₁ (F x) (G x) (FF x xx) (α x)).
Definition opcartesian_factorisation_disp_functor_cell_axioms
: disp_nat_trans_axioms opcartesian_factorisation_disp_functor_cell_data.
Show proof.
Definition opcartesian_factorisation_disp_functor_cell
: disp_nat_trans
α
FF
opcartesian_factorisation_disp_functor_data.
Show proof.
Definition opcartesian_factorisation_disp_functor_cell_is_opcartesian
{x : C₁}
(xx : D₁ x)
: is_opcartesian (opcartesian_factorisation_disp_functor_cell x xx).
Show proof.
End OpCartesianFactorisationDispFunctor.
Section fiber_functor_from_cleaving.
Context {C : category} (D : disp_cat C) (F : cleaving D).
Context {c c' : C} (f : C⟦c', c⟧).
Let lift_f : ∏ d : D c, cartesian_lift d f := F _ _ f.
Definition fiber_functor_from_cleaving_data : functor_data (D [{c}]) (D [{c'}]).
Show proof.
Lemma is_functor_from_cleaving_data : is_functor fiber_functor_from_cleaving_data.
Show proof.
Definition fiber_functor_from_cleaving : D [{c}] ⟶ D [{c'}]
:= make_functor _ is_functor_from_cleaving_data.
End fiber_functor_from_cleaving.
Section Essential_Surjectivity.
Definition fiber_functor_ess_split_surj
{C C' : category} {D} {D'}
{F : functor C C'} (FF : disp_functor F D D')
(H : disp_functor_ff FF)
{X : disp_functor_ess_split_surj FF}
{Y : is_op_isofibration D}
(x : C)
: ∏ yy : D'[{F x}], ∑ xx : D[{x}],
z_iso (fiber_functor FF _ xx) yy.
Show proof.
End Essential_Surjectivity.
Context {C₁ C₂ : category}
{F₁ F₂ F₃ : C₁ ⟶ C₂}
{α : F₁ ⟹ F₂}
{β : F₂ ⟹ F₃}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
{FF₁ : disp_functor F₁ D₁ D₂}
{FF₂ : disp_functor F₂ D₁ D₂}
{FF₃ : disp_functor F₃ D₁ D₂}
(αα : disp_nat_trans α FF₁ FF₂)
(ββ : disp_nat_trans (nat_trans_comp _ _ _ α β) FF₁ FF₃)
(Hαα : ∏ (x : C₁) (xx : D₁ x), is_opcartesian (αα x xx)).
Definition opcartesian_factorisation_disp_nat_trans_data
: disp_nat_trans_data β FF₂ FF₃
:= λ x xx, opcartesian_factorisation (Hαα x xx) (β x) (ββ x xx).
Definition opcartesian_factorisation_disp_nat_trans_axioms
: disp_nat_trans_axioms opcartesian_factorisation_disp_nat_trans_data.
Show proof.
intros x y f xx yy ff ; cbn in *.
unfold opcartesian_factorisation_disp_nat_trans_data.
use (opcartesian_factorisation_unique (Hαα x xx)).
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite !assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
etrans.
{
apply maponpaths.
apply maponpaths_2.
apply (disp_nat_trans_ax_var αα ff).
}
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
etrans.
{
apply maponpaths.
exact (disp_nat_trans_ax ββ ff).
}
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
unfold opcartesian_factorisation_disp_nat_trans_data.
use (opcartesian_factorisation_unique (Hαα x xx)).
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite !assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
etrans.
{
apply maponpaths.
apply maponpaths_2.
apply (disp_nat_trans_ax_var αα ff).
}
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
etrans.
{
apply maponpaths.
exact (disp_nat_trans_ax ββ ff).
}
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition opcartesian_factorisation_disp_nat_trans
: disp_nat_trans β FF₂ FF₃.
Show proof.
simple refine (_ ,, _).
- exact opcartesian_factorisation_disp_nat_trans_data.
- exact opcartesian_factorisation_disp_nat_trans_axioms.
End OpCartesianFactorisationDispNatTrans.- exact opcartesian_factorisation_disp_nat_trans_data.
- exact opcartesian_factorisation_disp_nat_trans_axioms.
Section OpCartesianFactorisationDispFunctor.
Context {C₁ C₂ : category}
{D₁ : disp_cat C₁}
{D₂ : disp_cat C₂}
(HD₁ : opcleaving D₂)
{F G : C₁ ⟶ C₂}
(FF : disp_functor F D₁ D₂)
(α : F ⟹ G).
Definition opcartesian_factorisation_disp_functor_data
: disp_functor_data G D₁ D₂.
Show proof.
simple refine (_ ,, _).
- exact (λ x xx, ob_of_opcartesian_lift _ (HD₁ (F x) (G x) (FF x xx) (α x))).
- exact (λ x y xx yy f ff,
opcartesian_factorisation
(mor_of_opcartesian_lift_is_opcartesian
_
(HD₁ (F x) (G x) (FF x xx) (α x)))
_
(transportf
(λ z, _ -->[ z ] _)
(nat_trans_ax α _ _ f)
(♯ FF ff
;;
mor_of_opcartesian_lift
_
(HD₁ (F y) (G y) (FF y yy) (α y))))).
- exact (λ x xx, ob_of_opcartesian_lift _ (HD₁ (F x) (G x) (FF x xx) (α x))).
- exact (λ x y xx yy f ff,
opcartesian_factorisation
(mor_of_opcartesian_lift_is_opcartesian
_
(HD₁ (F x) (G x) (FF x xx) (α x)))
_
(transportf
(λ z, _ -->[ z ] _)
(nat_trans_ax α _ _ f)
(♯ FF ff
;;
mor_of_opcartesian_lift
_
(HD₁ (F y) (G y) (FF y yy) (α y))))).
Definition opcartesian_factorisation_disp_functor_axioms
: disp_functor_axioms opcartesian_factorisation_disp_functor_data.
Show proof.
repeat split.
- intros x xx ; cbn.
use (opcartesian_factorisation_unique
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))).
rewrite opcartesian_factorisation_commutes.
rewrite disp_functor_id.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x y z xx yy zz f g ff hh ; cbn.
use (opcartesian_factorisation_unique
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))).
unfold transportb.
rewrite opcartesian_factorisation_commutes.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite mor_disp_transportf_postwhisker.
rewrite !transport_f_f.
rewrite !assoc_disp.
unfold transportb.
rewrite !transport_f_f.
rewrite opcartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite !assoc_disp_var.
unfold transportb.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x xx ; cbn.
use (opcartesian_factorisation_unique
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))).
rewrite opcartesian_factorisation_commutes.
rewrite disp_functor_id.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- intros x y z xx yy zz f g ff hh ; cbn.
use (opcartesian_factorisation_unique
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))).
unfold transportb.
rewrite opcartesian_factorisation_commutes.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite mor_disp_transportf_postwhisker.
rewrite !transport_f_f.
rewrite !assoc_disp.
unfold transportb.
rewrite !transport_f_f.
rewrite opcartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite !assoc_disp_var.
unfold transportb.
rewrite transport_f_f.
rewrite opcartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition opcartesian_factorisation_disp_functor
: disp_functor G D₁ D₂.
Show proof.
simple refine (_ ,, _).
- exact opcartesian_factorisation_disp_functor_data.
- exact opcartesian_factorisation_disp_functor_axioms.
- exact opcartesian_factorisation_disp_functor_data.
- exact opcartesian_factorisation_disp_functor_axioms.
Definition opcartesian_factorisation_disp_functor_is_opcartesian
(HFF : is_opcartesian_disp_functor FF)
: is_opcartesian_disp_functor opcartesian_factorisation_disp_functor.
Show proof.
intros x y f xx yy ff Hff ; cbn.
pose (HFff := HFF _ _ _ _ _ _ Hff).
use (is_opcartesian_postcomp
(idpath _)
_
(pr22 (HD₁ (F y) (G y) (FF y yy) (α y)))
(is_opcartesian_transportf
(nat_trans_ax α _ _ f)
(is_opcartesian_comp_disp
HFff
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))))).
rewrite opcartesian_factorisation_commutes.
apply idpath.
pose (HFff := HFF _ _ _ _ _ _ Hff).
use (is_opcartesian_postcomp
(idpath _)
_
(pr22 (HD₁ (F y) (G y) (FF y yy) (α y)))
(is_opcartesian_transportf
(nat_trans_ax α _ _ f)
(is_opcartesian_comp_disp
HFff
(pr22 (HD₁ (F x) (G x) (FF x xx) (α x)))))).
rewrite opcartesian_factorisation_commutes.
apply idpath.
Definition opcartesian_factorisation_disp_functor_cell_data
: disp_nat_trans_data α FF opcartesian_factorisation_disp_functor_data
:= λ x xx, pr12 (HD₁ (F x) (G x) (FF x xx) (α x)).
Definition opcartesian_factorisation_disp_functor_cell_axioms
: disp_nat_trans_axioms opcartesian_factorisation_disp_functor_cell_data.
Show proof.
intros x y f xx yy ff ; cbn ; unfold opcartesian_factorisation_disp_functor_cell_data.
unfold transportb.
rewrite opcartesian_factorisation_commutes.
rewrite transport_f_f.
refine (!_).
apply transportf_set.
apply homset_property.
unfold transportb.
rewrite opcartesian_factorisation_commutes.
rewrite transport_f_f.
refine (!_).
apply transportf_set.
apply homset_property.
Definition opcartesian_factorisation_disp_functor_cell
: disp_nat_trans
α
FF
opcartesian_factorisation_disp_functor_data.
Show proof.
simple refine (_ ,, _).
- exact opcartesian_factorisation_disp_functor_cell_data.
- exact opcartesian_factorisation_disp_functor_cell_axioms.
- exact opcartesian_factorisation_disp_functor_cell_data.
- exact opcartesian_factorisation_disp_functor_cell_axioms.
Definition opcartesian_factorisation_disp_functor_cell_is_opcartesian
{x : C₁}
(xx : D₁ x)
: is_opcartesian (opcartesian_factorisation_disp_functor_cell x xx).
Show proof.
End OpCartesianFactorisationDispFunctor.
Section fiber_functor_from_cleaving.
Context {C : category} (D : disp_cat C) (F : cleaving D).
Context {c c' : C} (f : C⟦c', c⟧).
Let lift_f : ∏ d : D c, cartesian_lift d f := F _ _ f.
Definition fiber_functor_from_cleaving_data : functor_data (D [{c}]) (D [{c'}]).
Show proof.
use tpair.
+ intro d. exact (object_of_cartesian_lift _ _ (lift_f d)).
+ intros d' d ff. cbn.
set (XR' := @cartesian_factorisation C D _ _ f).
specialize (XR' _ _ _ (lift_f d)).
use XR'.
* use (transportf (mor_disp _ _ )
_
(mor_disp_of_cartesian_lift _ _ (lift_f d') ;; ff)).
etrans; [ apply id_right |]; apply pathsinv0; apply id_left.
+ intro d. exact (object_of_cartesian_lift _ _ (lift_f d)).
+ intros d' d ff. cbn.
set (XR' := @cartesian_factorisation C D _ _ f).
specialize (XR' _ _ _ (lift_f d)).
use XR'.
* use (transportf (mor_disp _ _ )
_
(mor_disp_of_cartesian_lift _ _ (lift_f d') ;; ff)).
etrans; [ apply id_right |]; apply pathsinv0; apply id_left.
Lemma is_functor_from_cleaving_data : is_functor fiber_functor_from_cleaving_data.
Show proof.
split.
- intro d; cbn.
apply pathsinv0.
apply path_to_ctr.
etrans; [apply id_left_disp |].
apply pathsinv0.
etrans. { apply maponpaths. apply id_right_disp. }
etrans; [ apply transport_f_f |].
unfold transportb.
apply maponpaths_2.
apply homset_property.
- intros d'' d' d ff' ff; cbn.
apply pathsinv0.
apply path_to_ctr.
etrans; [apply mor_disp_transportf_postwhisker |].
apply pathsinv0.
etrans. { apply maponpaths; apply mor_disp_transportf_prewhisker. }
etrans; [apply transport_f_f |].
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [apply assoc_disp_var |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans ; [ apply maponpaths, cartesian_factorisation_commutes |].
etrans ; [ apply mor_disp_transportf_prewhisker |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [ apply assoc_disp |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [ apply maponpaths_2, cartesian_factorisation_commutes |].
etrans; [ apply mor_disp_transportf_postwhisker |].
etrans. { apply maponpaths. apply assoc_disp_var. }
etrans. { apply transport_f_f. }
apply maponpaths_2, homset_property.
- intro d; cbn.
apply pathsinv0.
apply path_to_ctr.
etrans; [apply id_left_disp |].
apply pathsinv0.
etrans. { apply maponpaths. apply id_right_disp. }
etrans; [ apply transport_f_f |].
unfold transportb.
apply maponpaths_2.
apply homset_property.
- intros d'' d' d ff' ff; cbn.
apply pathsinv0.
apply path_to_ctr.
etrans; [apply mor_disp_transportf_postwhisker |].
apply pathsinv0.
etrans. { apply maponpaths; apply mor_disp_transportf_prewhisker. }
etrans; [apply transport_f_f |].
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [apply assoc_disp_var |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans ; [ apply maponpaths, cartesian_factorisation_commutes |].
etrans ; [ apply mor_disp_transportf_prewhisker |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [ apply assoc_disp |].
apply pathsinv0.
apply transportf_comp_lemma.
apply pathsinv0.
etrans; [ apply maponpaths_2, cartesian_factorisation_commutes |].
etrans; [ apply mor_disp_transportf_postwhisker |].
etrans. { apply maponpaths. apply assoc_disp_var. }
etrans. { apply transport_f_f. }
apply maponpaths_2, homset_property.
Definition fiber_functor_from_cleaving : D [{c}] ⟶ D [{c'}]
:= make_functor _ is_functor_from_cleaving_data.
End fiber_functor_from_cleaving.
Section Essential_Surjectivity.
Definition fiber_functor_ess_split_surj
{C C' : category} {D} {D'}
{F : functor C C'} (FF : disp_functor F D D')
(H : disp_functor_ff FF)
{X : disp_functor_ess_split_surj FF}
{Y : is_op_isofibration D}
(x : C)
: ∏ yy : D'[{F x}], ∑ xx : D[{x}],
z_iso (fiber_functor FF _ xx) yy.
Show proof.
intro yy.
set (XR := X _ yy).
destruct XR as [c'' [i [xx' ii]]].
set (YY := Y _ _ i xx').
destruct YY as [ dd pe ].
use tpair.
- apply dd.
-
set (XR := disp_functor_on_z_iso_disp FF pe).
set (XR' := z_iso_inv_from_z_iso_disp XR).
apply (invweq (z_iso_disp_z_iso_fiber _ _ _ _)).
set (XRt := z_iso_disp_comp XR' ii).
transparent assert (XH :
(z_iso_comp (z_iso_inv_from_z_iso (functor_on_z_iso F i))
(functor_on_z_iso F i) = identity_z_iso _ )).
{ apply z_iso_eq. cbn.
etrans.
{ apply pathsinv0, functor_comp. }
apply functor_id_id.
apply z_iso_after_z_iso_inv.
}
set (XRT := transportf (λ r, z_iso_disp r (FF x dd) yy )
XH).
apply XRT.
assumption.
set (XR := X _ yy).
destruct XR as [c'' [i [xx' ii]]].
set (YY := Y _ _ i xx').
destruct YY as [ dd pe ].
use tpair.
- apply dd.
-
set (XR := disp_functor_on_z_iso_disp FF pe).
set (XR' := z_iso_inv_from_z_iso_disp XR).
apply (invweq (z_iso_disp_z_iso_fiber _ _ _ _)).
set (XRt := z_iso_disp_comp XR' ii).
transparent assert (XH :
(z_iso_comp (z_iso_inv_from_z_iso (functor_on_z_iso F i))
(functor_on_z_iso F i) = identity_z_iso _ )).
{ apply z_iso_eq. cbn.
etrans.
{ apply pathsinv0, functor_comp. }
apply functor_id_id.
apply z_iso_after_z_iso_inv.
}
set (XRT := transportf (λ r, z_iso_disp r (FF x dd) yy )
XH).
apply XRT.
assumption.
End Essential_Surjectivity.
A sufficient condition for when a cartesian factorization is an isomorphism
Definition is_z_iso_disp_cartesian_factorisation
{C : category}
{D : disp_cat C}
{w x y : C}
{f : w --> x}
(Hf : is_z_isomorphism f)
(fiso := (f ,, Hf) : z_iso w x)
{g : x --> y}
(Hg : is_z_isomorphism g)
(giso := (g ,, Hg) : z_iso x y)
{ww : D w}
{xx : D x}
{yy : D y}
{gg : xx -->[ g ] yy}
(Hgg : is_cartesian gg)
(hh : ww -->[ f · g ] yy)
(Hhh : is_z_iso_disp (z_iso_comp fiso giso) hh)
: is_z_iso_disp
fiso
(cartesian_factorisation Hgg f hh).
Show proof.
{C : category}
{D : disp_cat C}
{w x y : C}
{f : w --> x}
(Hf : is_z_isomorphism f)
(fiso := (f ,, Hf) : z_iso w x)
{g : x --> y}
(Hg : is_z_isomorphism g)
(giso := (g ,, Hg) : z_iso x y)
{ww : D w}
{xx : D x}
{yy : D y}
{gg : xx -->[ g ] yy}
(Hgg : is_cartesian gg)
(hh : ww -->[ f · g ] yy)
(Hhh : is_z_iso_disp (z_iso_comp fiso giso) hh)
: is_z_iso_disp
fiso
(cartesian_factorisation Hgg f hh).
Show proof.
simple refine (_ ,, _ ,, _).
- refine (transportf
(λ z, _ -->[ z ] _)
_
(gg ;; inv_mor_disp_from_z_iso Hhh)%mor_disp).
abstract
(cbn ;
rewrite !assoc ;
refine (_ @ id_left _) ;
apply maponpaths_2 ;
exact (z_iso_inv_after_z_iso giso)).
- use (cartesian_factorisation_unique Hgg).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite assoc_disp_var.
rewrite !mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
etrans ;
[ do 2 apply maponpaths ;
apply (z_iso_disp_after_inv_mor Hhh)
| ].
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite id_right_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- cbn.
rewrite mor_disp_transportf_prewhisker.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
refine (maponpaths _ (inv_mor_after_z_iso_disp Hhh) @ _).
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
- refine (transportf
(λ z, _ -->[ z ] _)
_
(gg ;; inv_mor_disp_from_z_iso Hhh)%mor_disp).
abstract
(cbn ;
rewrite !assoc ;
refine (_ @ id_left _) ;
apply maponpaths_2 ;
exact (z_iso_inv_after_z_iso giso)).
- use (cartesian_factorisation_unique Hgg).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite assoc_disp_var.
rewrite !mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
etrans ;
[ do 2 apply maponpaths ;
apply (z_iso_disp_after_inv_mor Hhh)
| ].
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite id_right_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite id_left_disp.
unfold transportb.
rewrite !transport_f_f.
apply maponpaths_2.
apply homset_property.
- cbn.
rewrite mor_disp_transportf_prewhisker.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
refine (maponpaths _ (inv_mor_after_z_iso_disp Hhh) @ _).
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
The fiber functor of the identity
Section FiberFunctorCleavingIdenttiy.
Context {C : category}
{D : disp_cat C}
(HD : cleaving D)
(x : C).
Definition fiber_functor_from_cleaving_identity_data
: nat_trans_data
(functor_identity _)
(fiber_functor_from_cleaving D HD (identity x)).
Show proof.
Proposition fiber_functor_from_cleaving_identity_laws
: is_nat_trans
_ _
fiber_functor_from_cleaving_identity_data.
Show proof.
Definition fiber_functor_from_cleaving_identity
: functor_identity _
⟹
fiber_functor_from_cleaving D HD (identity x).
Show proof.
Definition is_nat_z_iso_fiber_functor_from_cleaving_identity
: is_nat_z_iso fiber_functor_from_cleaving_identity.
Show proof.
Arguments fiber_functor_from_cleaving_identity_data {C D} HD x /.
Context {C : category}
{D : disp_cat C}
(HD : cleaving D)
(x : C).
Definition fiber_functor_from_cleaving_identity_data
: nat_trans_data
(functor_identity _)
(fiber_functor_from_cleaving D HD (identity x)).
Show proof.
intros xx.
refine (cartesian_factorisation
(cartesian_lift_is_cartesian _ _ (HD x x (identity x) xx))
(identity x)
(transportb
(λ z, _ -->[ z ] _)
_
(id_disp _))).
abstract (exact (id_left _)).
refine (cartesian_factorisation
(cartesian_lift_is_cartesian _ _ (HD x x (identity x) xx))
(identity x)
(transportb
(λ z, _ -->[ z ] _)
_
(id_disp _))).
abstract (exact (id_left _)).
Proposition fiber_functor_from_cleaving_identity_laws
: is_nat_trans
_ _
fiber_functor_from_cleaving_identity_data.
Show proof.
intros xx yy f ; cbn.
unfold fiber_functor_from_cleaving_identity_data.
use (cartesian_factorisation_unique (HD x x (identity x) yy)).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_from_cleaving_identity_data.
use (cartesian_factorisation_unique (HD x x (identity x) yy)).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
rewrite id_right_disp.
unfold transportb.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite !transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition fiber_functor_from_cleaving_identity
: functor_identity _
⟹
fiber_functor_from_cleaving D HD (identity x).
Show proof.
use make_nat_trans.
- exact fiber_functor_from_cleaving_identity_data.
- exact fiber_functor_from_cleaving_identity_laws.
- exact fiber_functor_from_cleaving_identity_data.
- exact fiber_functor_from_cleaving_identity_laws.
Definition is_nat_z_iso_fiber_functor_from_cleaving_identity
: is_nat_z_iso fiber_functor_from_cleaving_identity.
Show proof.
intros xx ; cbn.
use is_z_iso_fiber_from_is_z_iso_disp.
use is_z_iso_disp_cartesian_factorisation.
{
apply is_z_isomorphism_identity.
}
cbn in x.
use (is_z_iso_disp_transportb_fun_eq
(identity_z_iso x)
(id_disp xx)).
apply id_is_z_iso_disp.
End FiberFunctorCleavingIdenttiy.use is_z_iso_fiber_from_is_z_iso_disp.
use is_z_iso_disp_cartesian_factorisation.
{
apply is_z_isomorphism_identity.
}
cbn in x.
use (is_z_iso_disp_transportb_fun_eq
(identity_z_iso x)
(id_disp xx)).
apply id_is_z_iso_disp.
Arguments fiber_functor_from_cleaving_identity_data {C D} HD x /.
The fiber functor of a compositio
Section FiberFunctorCleavingComp.
Context {C : category}
{D : disp_cat C}
(HD : cleaving D)
{x y z : C}
(f : y --> x)
(g : z --> y).
Definition fiber_functor_from_cleaving_comp_data
: nat_trans_data
(fiber_functor_from_cleaving D HD f ∙ fiber_functor_from_cleaving D HD g)
(fiber_functor_from_cleaving D HD (g · f)).
Show proof.
Proposition fiber_functor_from_cleaving_comp_laws
: is_nat_trans
_ _
fiber_functor_from_cleaving_comp_data.
Show proof.
Definition fiber_functor_from_cleaving_comp
: fiber_functor_from_cleaving D HD f ∙ fiber_functor_from_cleaving D HD g
⟹
fiber_functor_from_cleaving D HD (g · f).
Show proof.
Definition fiber_functor_from_cleaving_comp_inv
(xx : D x)
: D[{z}] ⟦ pr1 (HD x z (g · f) xx) , pr1 (HD y z g (HD x y f xx)) ⟧.
Show proof.
Proposition fiber_functor_from_cleaving_comp_inv_left
(xx : D x)
: fiber_functor_from_cleaving_comp xx · fiber_functor_from_cleaving_comp_inv xx
=
identity _.
Show proof.
Proposition fiber_functor_from_cleaving_comp_inv_right
(xx : D x)
: fiber_functor_from_cleaving_comp_inv xx · fiber_functor_from_cleaving_comp xx
=
identity _.
Show proof.
Definition is_nat_z_iso_fiber_functor_from_cleaving_comp
: is_nat_z_iso fiber_functor_from_cleaving_comp.
Show proof.
Arguments fiber_functor_from_cleaving_comp_data {C D} HD {x y z} f g /.
Context {C : category}
{D : disp_cat C}
(HD : cleaving D)
{x y z : C}
(f : y --> x)
(g : z --> y).
Definition fiber_functor_from_cleaving_comp_data
: nat_trans_data
(fiber_functor_from_cleaving D HD f ∙ fiber_functor_from_cleaving D HD g)
(fiber_functor_from_cleaving D HD (g · f)).
Show proof.
intros xx.
refine (cartesian_factorisation
(cartesian_lift_is_cartesian _ _ (HD x z (g · f) xx))
_
(transportb
(λ z, _ -->[ z ] _)
_
(HD y z g (HD x y f xx) ;; HD x y f xx)%mor_disp)).
abstract
(exact (id_left _)).
refine (cartesian_factorisation
(cartesian_lift_is_cartesian _ _ (HD x z (g · f) xx))
_
(transportb
(λ z, _ -->[ z ] _)
_
(HD y z g (HD x y f xx) ;; HD x y f xx)%mor_disp)).
abstract
(exact (id_left _)).
Proposition fiber_functor_from_cleaving_comp_laws
: is_nat_trans
_ _
fiber_functor_from_cleaving_comp_data.
Show proof.
intros xx yy gg ; cbn.
unfold fiber_functor_from_cleaving_comp_data.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite cartesian_factorisation_commutes.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
refine (!_).
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_from_cleaving_comp_data.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite cartesian_factorisation_commutes.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
refine (!_).
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
rewrite assoc_disp_var.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition fiber_functor_from_cleaving_comp
: fiber_functor_from_cleaving D HD f ∙ fiber_functor_from_cleaving D HD g
⟹
fiber_functor_from_cleaving D HD (g · f).
Show proof.
use make_nat_trans.
- exact fiber_functor_from_cleaving_comp_data.
- exact fiber_functor_from_cleaving_comp_laws.
- exact fiber_functor_from_cleaving_comp_data.
- exact fiber_functor_from_cleaving_comp_laws.
Definition fiber_functor_from_cleaving_comp_inv
(xx : D x)
: D[{z}] ⟦ pr1 (HD x z (g · f) xx) , pr1 (HD y z g (HD x y f xx)) ⟧.
Show proof.
refine (cartesian_factorisation
(HD y z g (HD x y f xx))
_
(cartesian_factorisation
(HD x y f xx)
_
(transportf
(λ z, _ -->[ z ] _)
_
(HD x z (g · f) xx)))).
abstract
(rewrite !assoc' ;
rewrite id_left ;
apply idpath).
(HD y z g (HD x y f xx))
_
(cartesian_factorisation
(HD x y f xx)
_
(transportf
(λ z, _ -->[ z ] _)
_
(HD x z (g · f) xx)))).
abstract
(rewrite !assoc' ;
rewrite id_left ;
apply idpath).
Proposition fiber_functor_from_cleaving_comp_inv_left
(xx : D x)
: fiber_functor_from_cleaving_comp xx · fiber_functor_from_cleaving_comp_inv xx
=
identity _.
Show proof.
cbn.
unfold fiber_functor_from_cleaving_comp_data, fiber_functor_from_cleaving_comp_inv.
unfold transportb.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
rewrite mor_disp_transportf_postwhisker.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_from_cleaving_comp_data, fiber_functor_from_cleaving_comp_inv.
unfold transportb.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
rewrite mor_disp_transportf_postwhisker.
apply maponpaths_2.
apply homset_property.
Proposition fiber_functor_from_cleaving_comp_inv_right
(xx : D x)
: fiber_functor_from_cleaving_comp_inv xx · fiber_functor_from_cleaving_comp xx
=
identity _.
Show proof.
cbn.
unfold fiber_functor_from_cleaving_comp_data, fiber_functor_from_cleaving_comp_inv.
unfold transportb.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite !cartesian_factorisation_commutes.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_from_cleaving_comp_data, fiber_functor_from_cleaving_comp_inv.
unfold transportb.
use (cartesian_factorisation_unique (HD _ _ _ _)).
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite !cartesian_factorisation_commutes.
rewrite transport_f_f.
rewrite id_left_disp.
unfold transportb.
apply maponpaths_2.
apply homset_property.
Definition is_nat_z_iso_fiber_functor_from_cleaving_comp
: is_nat_z_iso fiber_functor_from_cleaving_comp.
Show proof.
intros xx.
use make_is_z_isomorphism.
- cbn -[fiber_category].
exact (fiber_functor_from_cleaving_comp_inv xx).
- split.
+ exact (fiber_functor_from_cleaving_comp_inv_left xx).
+ exact (fiber_functor_from_cleaving_comp_inv_right xx).
End FiberFunctorCleavingComp.use make_is_z_isomorphism.
- cbn -[fiber_category].
exact (fiber_functor_from_cleaving_comp_inv xx).
- split.
+ exact (fiber_functor_from_cleaving_comp_inv_left xx).
+ exact (fiber_functor_from_cleaving_comp_inv_right xx).
Arguments fiber_functor_from_cleaving_comp_data {C D} HD {x y z} f g /.
The fiber functor of a cartesian functor is natural
Locate cartesian_disp_functor_on_cartesian.
Section FiberFunctorNatural.
Context {C : category}
{D₁ D₂ : disp_cat C}
(HD₁ : cleaving D₁)
(HD₂ : cleaving D₂)
(F : cartesian_disp_functor (functor_identity C) D₁ D₂)
{x y : C}
(f : y --> x).
Definition fiber_functor_natural_data
: nat_trans_data
(fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f)
(fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y).
Show proof.
: is_nat_trans
_ _
fiber_functor_natural_data.
Show proof.
Definition fiber_functor_natural
: fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f
⟹
fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y.
Show proof.
Definition fiber_functor_natural_inv
(xx : D₁ x)
: F y (HD₁ x y f xx) -->[ identity y] pr1 (HD₂ x y f (F x xx)).
Show proof.
Proposition fiber_functor_natural_inv_left
(xx : D₁ x)
: fiber_functor_natural xx · fiber_functor_natural_inv xx
=
identity _.
Show proof.
Proposition fiber_functor_natural_inv_right
(xx : D₁ x)
: transportf
(λ z, _ -->[ z ] _)
(id_right (identity y))
(fiber_functor_natural_inv xx ;; fiber_functor_natural_data xx)%mor_disp
=
id_disp _.
Show proof.
Definition is_nat_z_iso_fiber_functor_natural
: is_nat_z_iso fiber_functor_natural.
Show proof.
Definition fiber_functor_natural_nat_z_iso
: nat_z_iso
(fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f)
(fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y).
Show proof.
End FiberFunctorNatural.
Arguments fiber_functor_natural_data {C D₁ D₂} HD₁ HD₂ F {x y} f /.
Section FiberFunctorNatural.
Context {C : category}
{D₁ D₂ : disp_cat C}
(HD₁ : cleaving D₁)
(HD₂ : cleaving D₂)
(F : cartesian_disp_functor (functor_identity C) D₁ D₂)
{x y : C}
(f : y --> x).
Definition fiber_functor_natural_data
: nat_trans_data
(fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f)
(fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y).
Show proof.
intro xx.
refine (cartesian_factorisation
(cartesian_disp_functor_on_cartesian F (HD₁ x y f xx))
_
(transportf
(λ z, _ -->[ z ] _)
_
(HD₂ x y f (F x xx)))).
abstract
(exact (!(id_left _))).
Proposition fiber_functor_natural_lawsrefine (cartesian_factorisation
(cartesian_disp_functor_on_cartesian F (HD₁ x y f xx))
_
(transportf
(λ z, _ -->[ z ] _)
_
(HD₂ x y f (F x xx)))).
abstract
(exact (!(id_left _))).
: is_nat_trans
_ _
fiber_functor_natural_data.
Show proof.
intros xx yy ff.
unfold fiber_functor_natural_data ; cbn.
use (cartesian_factorisation_unique
(cartesian_disp_functor_on_cartesian F (HD₁ _ _ _ _))).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
refine (!_).
rewrite assoc_disp_var.
rewrite transport_f_f.
etrans.
{
do 2 apply maponpaths.
refine (!_).
apply (disp_functor_comp_var F).
}
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_transportf.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_natural_data ; cbn.
use (cartesian_factorisation_unique
(cartesian_disp_functor_on_cartesian F (HD₁ _ _ _ _))).
rewrite !mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite !transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
refine (!_).
rewrite assoc_disp_var.
rewrite transport_f_f.
etrans.
{
do 2 apply maponpaths.
refine (!_).
apply (disp_functor_comp_var F).
}
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite disp_functor_transportf.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite disp_functor_comp.
unfold transportb.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite assoc_disp.
unfold transportb.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_postwhisker.
rewrite transport_f_f.
apply maponpaths_2.
apply homset_property.
Definition fiber_functor_natural
: fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f
⟹
fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y.
Show proof.
Definition fiber_functor_natural_inv
(xx : D₁ x)
: F y (HD₁ x y f xx) -->[ identity y] pr1 (HD₂ x y f (F x xx)).
Show proof.
refine (cartesian_factorisation
(HD₂ _ _ _ _)
_
(transportf
(λ z, _ -->[ z ] _)
_
(♯ F (pr12 (HD₁ x y f xx)))))%mor_disp.
abstract
(exact (!(id_left _))).
(HD₂ _ _ _ _)
_
(transportf
(λ z, _ -->[ z ] _)
_
(♯ F (pr12 (HD₁ x y f xx)))))%mor_disp.
abstract
(exact (!(id_left _))).
Proposition fiber_functor_natural_inv_left
(xx : D₁ x)
: fiber_functor_natural xx · fiber_functor_natural_inv xx
=
identity _.
Show proof.
cbn.
unfold fiber_functor_natural_data, fiber_functor_natural_inv ; cbn.
use (cartesian_factorisation_unique (HD₂ _ _ _ _)).
rewrite id_left_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
unfold transportb.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_natural_data, fiber_functor_natural_inv ; cbn.
use (cartesian_factorisation_unique (HD₂ _ _ _ _)).
rewrite id_left_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
unfold transportb.
apply maponpaths_2.
apply homset_property.
Proposition fiber_functor_natural_inv_right
(xx : D₁ x)
: transportf
(λ z, _ -->[ z ] _)
(id_right (identity y))
(fiber_functor_natural_inv xx ;; fiber_functor_natural_data xx)%mor_disp
=
id_disp _.
Show proof.
cbn.
unfold fiber_functor_natural_data, fiber_functor_natural_inv ; cbn.
use (cartesian_factorisation_unique
(cartesian_disp_functor_on_cartesian F (HD₁ _ _ _ _))).
rewrite id_left_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
unfold transportb.
apply maponpaths_2.
apply homset_property.
unfold fiber_functor_natural_data, fiber_functor_natural_inv ; cbn.
use (cartesian_factorisation_unique
(cartesian_disp_functor_on_cartesian F (HD₁ _ _ _ _))).
rewrite id_left_disp.
rewrite mor_disp_transportf_postwhisker.
rewrite assoc_disp_var.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite mor_disp_transportf_prewhisker.
rewrite transport_f_f.
rewrite cartesian_factorisation_commutes.
rewrite transport_f_f.
unfold transportb.
apply maponpaths_2.
apply homset_property.
Definition is_nat_z_iso_fiber_functor_natural
: is_nat_z_iso fiber_functor_natural.
Show proof.
intros xx.
use make_is_z_isomorphism.
- exact (fiber_functor_natural_inv xx).
- split.
+ exact (fiber_functor_natural_inv_left xx).
+ exact (fiber_functor_natural_inv_right xx).
use make_is_z_isomorphism.
- exact (fiber_functor_natural_inv xx).
- split.
+ exact (fiber_functor_natural_inv_left xx).
+ exact (fiber_functor_natural_inv_right xx).
Definition fiber_functor_natural_nat_z_iso
: nat_z_iso
(fiber_functor F x ∙ fiber_functor_from_cleaving D₂ HD₂ f)
(fiber_functor_from_cleaving D₁ HD₁ f ∙ fiber_functor F y).
Show proof.
End FiberFunctorNatural.
Arguments fiber_functor_natural_data {C D₁ D₂} HD₁ HD₂ F {x y} f /.
Lemma for composing `idtoiso` with a cartesian lift
Proposition idtoiso_disp_cartesian_lift
{C : category}
(D : disp_cat C)
(HD : cleaving D)
{x y : C}
{f g : x --> y}
(yy : D y)
(p : g = f)
: (idtoiso_disp
(idpath _)
(maponpaths (λ (h : x --> y), pr1 (HD _ _ h _)) p)
;; HD y x f yy
=
transportf
(λ z, _ -->[ z ] _)
(p @ !(id_left _))
(HD y x g yy))%mor_disp.
Show proof.
{C : category}
(D : disp_cat C)
(HD : cleaving D)
{x y : C}
{f g : x --> y}
(yy : D y)
(p : g = f)
: (idtoiso_disp
(idpath _)
(maponpaths (λ (h : x --> y), pr1 (HD _ _ h _)) p)
;; HD y x f yy
=
transportf
(λ z, _ -->[ z ] _)
(p @ !(id_left _))
(HD y x g yy))%mor_disp.
Show proof.
Transporting the object of a cartesian lift
Proposition transportf_object_cartesian_lift
{C : category}
{D : disp_cat C}
(HD : cleaving D)
{x : C}
(xx : D x)
{f g : x --> x}
(p : f = g)
(ff : xx -->[ identity x ] object_of_cartesian_lift _ _ (HD x x f xx))
: transportf
(λ (h : x --> x),
_ -->[ identity x ] object_of_cartesian_lift _ _ (HD x x h xx))
p
ff
=
cartesian_factorisation
(HD x x g xx)
_
(ff ;; transportf (λ z, _ -->[ z ] _) p (HD x x f xx))%mor_disp.
Show proof.
{C : category}
{D : disp_cat C}
(HD : cleaving D)
{x : C}
(xx : D x)
{f g : x --> x}
(p : f = g)
(ff : xx -->[ identity x ] object_of_cartesian_lift _ _ (HD x x f xx))
: transportf
(λ (h : x --> x),
_ -->[ identity x ] object_of_cartesian_lift _ _ (HD x x h xx))
p
ff
=
cartesian_factorisation
(HD x x g xx)
_
(ff ;; transportf (λ z, _ -->[ z ] _) p (HD x x f xx))%mor_disp.
Show proof.
induction p ; cbn.
use (cartesian_factorisation_unique (HD x x f xx)).
rewrite cartesian_factorisation_commutes.
apply idpath.
use (cartesian_factorisation_unique (HD x x f xx)).
rewrite cartesian_factorisation_commutes.
apply idpath.