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Prose for coherence-triangle-precomp-lift-family-of-elements
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VojtechStep committed Jan 12, 2024
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Original file line number Diff line number Diff line change
Expand Up @@ -151,50 +151,56 @@ module _
( triangle-precomp-lift-family-of-elements-htpy-refl-htpy)
```

### TODO
### `triangle-precomp-lift-family-of-elements-htpy` factors through transport along a homotopy in the famiy `B ∘ a`

Instead of defining the homotopy `triangle-precomp-lift-family-of-elements-htpy`
by homotopy induction, we could have defined it manually using the
characterization of transport in the type of lifts of a family of elements.

We show that these two definitions are homotopic.

```agda
module _
{l1 l2 l3 l4 : Level} {I : UU l1} {A : UU l2} (B : A UU l3) (a : I A)
{J : UU l4} {f : J I}
where

statement-coherence-triangle-precomp-lift-family-of-elements-htpy :
statement-coherence-triangle-precomp-lift-family-of-elements :
{g : J I} (H : f ~ g) UU (l1 ⊔ l3 ⊔ l4)
statement-coherence-triangle-precomp-lift-family-of-elements-htpy H =
statement-coherence-triangle-precomp-lift-family-of-elements H =
( triangle-precomp-lift-family-of-elements-htpy B a H) ~
( ( ( tr-lift-family-of-elements-precomp B a H) ·r
( precomp-lift-family-of-elements B f a)) ∙h
( λ b eq-htpy (λ j apd b (H j))))

coherence-triangle-precomp-lift-family-of-elements-htpy-refl-htpy :
statement-coherence-triangle-precomp-lift-family-of-elements-htpy
coherence-triangle-precomp-lift-family-of-elements-refl-htpy :
statement-coherence-triangle-precomp-lift-family-of-elements
( refl-htpy)
coherence-triangle-precomp-lift-family-of-elements-htpy-refl-htpy b =
coherence-triangle-precomp-lift-family-of-elements-refl-htpy b =
( htpy-eq (compute-triangle-precomp-lift-family-of-elements-htpy B a) b) ∙
( inv right-unit) ∙
( identification-left-whisk
( triangle-precomp-lift-family-of-elements-htpy-refl-htpy B a b)
( inv (eq-htpy-refl-htpy (b ∘ f))))

coherence-triangle-precomp-lift-family-of-elements-htpy :
coherence-triangle-precomp-lift-family-of-elements :
{g : J I} (H : f ~ g)
statement-coherence-triangle-precomp-lift-family-of-elements-htpy H
coherence-triangle-precomp-lift-family-of-elements-htpy =
statement-coherence-triangle-precomp-lift-family-of-elements H
coherence-triangle-precomp-lift-family-of-elements =
ind-htpy f
( λ g
statement-coherence-triangle-precomp-lift-family-of-elements-htpy)
( coherence-triangle-precomp-lift-family-of-elements-htpy-refl-htpy)
statement-coherence-triangle-precomp-lift-family-of-elements)
( coherence-triangle-precomp-lift-family-of-elements-refl-htpy)

abstract
compute-coherence-triangle-precomp-lift-family-of-elements-htpy :
coherence-triangle-precomp-lift-family-of-elements-htpy refl-htpy =
coherence-triangle-precomp-lift-family-of-elements-htpy-refl-htpy
compute-coherence-triangle-precomp-lift-family-of-elements-htpy =
compute-coherence-triangle-precomp-lift-family-of-elements :
coherence-triangle-precomp-lift-family-of-elements refl-htpy =
coherence-triangle-precomp-lift-family-of-elements-refl-htpy
compute-coherence-triangle-precomp-lift-family-of-elements =
compute-ind-htpy f
( λ g
statement-coherence-triangle-precomp-lift-family-of-elements-htpy)
( coherence-triangle-precomp-lift-family-of-elements-htpy-refl-htpy)
statement-coherence-triangle-precomp-lift-family-of-elements)
( coherence-triangle-precomp-lift-family-of-elements-refl-htpy)
```

### `precomp-lifted-family-of-elements` is homotopic to the precomposition map on functions up to equivalence
Expand Down Expand Up @@ -268,8 +274,8 @@ module _

### `coherence-square-precomp-map-inv-distributive-Π-Σ` commutes with induced homotopies between precompositions maps

Diagrammatically, we have two ways of composing homotopies to connect `- ∘ f` and
`precomp-lifted-family-of-elements g`. One factors through
Diagrammatically, we have two ways of composing homotopies to connect `- ∘ f`
and `precomp-lifted-family-of-elements g`. One factors through
`precomp-lifted-family-of-elements f`:

```text
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -284,7 +284,7 @@ pullback property.
( ( refl-htpy) ,
( refl-htpy) ,
( ( right-unit-htpy) ∙h
( coherence-triangle-precomp-lift-family-of-elements-htpy P id
( coherence-triangle-precomp-lift-family-of-elements P id
( coherence-square-cocone f g c))))
( is-pullback-cone-family-dependent-pullback-family P pp-c id)
```

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