Distinguish isomorphism of categories and of types
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@ -67,7 +67,7 @@ module _ {ℓa ℓb : Level} (ℂ : Category ℓa ℓb) where
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IsPreCategory.arrowsAreSets isPreCategory = arrowsAreSets
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module _ {A B : ℂ.Object} where
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eqv : isEquiv (A ≡ B) (A ≅ B) (Univalence.idToIso isIdentity A B)
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eqv : isEquiv (A ≡ B) (A ≊ B) (Univalence.idToIso isIdentity A B)
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eqv = {!!}
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univalent : Univalent
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@ -2,6 +2,7 @@
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module Cat.Categories.Fun where
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open import Cat.Prelude
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open import Cat.Equivalence
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open import Cat.Category
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open import Cat.Category.Functor
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@ -33,13 +34,140 @@ module Fun {ℓc ℓc' ℓd ℓd' : Level} (ℂ : Category ℓc ℓc') (𝔻 : C
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open IsPreCategory isPreCategory hiding (identity)
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module _ {F G : Functor ℂ 𝔻} (p : F ≡ G) where
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private
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module F = Functor F
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module G = Functor G
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p-omap : F.omap ≡ G.omap
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p-omap = cong Functor.omap p
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pp : {C : ℂ.Object} → 𝔻 [ Functor.omap F C , Functor.omap F C ] ≡ 𝔻 [ Functor.omap F C , Functor.omap G C ]
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pp {C} = cong (λ f → 𝔻 [ Functor.omap F C , f C ]) p-omap
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module _ {C : ℂ.Object} where
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p* : F.omap C ≡ G.omap C
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p* = cong (_$ C) p-omap
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iso : F.omap C 𝔻.≊ G.omap C
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iso = 𝔻.idToIso _ _ p*
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open Σ iso renaming (fst to f→g) public
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open Σ (snd iso) renaming (fst to g→f ; snd to inv) public
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lem : coe (pp {C}) 𝔻.identity ≡ f→g
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lem = trans (𝔻.9-1-9-right {b = Functor.omap F C} 𝔻.identity p*) 𝔻.rightIdentity
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idToNatTrans : NaturalTransformation F G
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idToNatTrans = (λ C → coe pp 𝔻.identity) , λ f → begin
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coe pp 𝔻.identity 𝔻.<<< F.fmap f ≡⟨ cong (𝔻._<<< F.fmap f) lem ⟩
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-- Just need to show that f→g is a natural transformation
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-- I know that it has an inverse; g→f
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f→g 𝔻.<<< F.fmap f ≡⟨ {!lem!} ⟩
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G.fmap f 𝔻.<<< f→g ≡⟨ cong (G.fmap f 𝔻.<<<_) (sym lem) ⟩
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G.fmap f 𝔻.<<< coe pp 𝔻.identity ∎
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module _ {A B : Functor ℂ 𝔻} where
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module A = Functor A
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module B = Functor B
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module _ (iso : A ≊ B) where
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omapEq : A.omap ≡ B.omap
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omapEq = funExt eq
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where
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module _ (C : ℂ.Object) where
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f : 𝔻.Arrow (A.omap C) (B.omap C)
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f = fst (fst iso) C
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g : 𝔻.Arrow (B.omap C) (A.omap C)
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g = fst (fst (snd iso)) C
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inv : 𝔻.IsInverseOf f g
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inv
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= ( begin
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g 𝔻.<<< f ≡⟨ cong (λ x → fst x $ C) (fst (snd (snd iso))) ⟩
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𝔻.identity ∎
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)
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, ( begin
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f 𝔻.<<< g ≡⟨ cong (λ x → fst x $ C) (snd (snd (snd iso))) ⟩
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𝔻.identity ∎
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)
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isoC : A.omap C 𝔻.≊ B.omap C
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isoC = f , g , inv
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eq : A.omap C ≡ B.omap C
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eq = 𝔻.isoToId isoC
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U : (F : ℂ.Object → 𝔻.Object) → Set _
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U F = {A B : ℂ.Object} → ℂ [ A , B ] → 𝔻 [ F A , F B ]
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module _
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(omap : ℂ.Object → 𝔻.Object)
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(p : A.omap ≡ omap)
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where
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D : Set _
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D = ( fmap : U omap)
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→ ( let
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raw-B : RawFunctor ℂ 𝔻
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raw-B = record { omap = omap ; fmap = fmap }
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)
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→ (isF-B' : IsFunctor ℂ 𝔻 raw-B)
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→ ( let
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B' : Functor ℂ 𝔻
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B' = record { raw = raw-B ; isFunctor = isF-B' }
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)
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→ (iso' : A ≊ B') → PathP (λ i → U (p i)) A.fmap fmap
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-- D : Set _
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-- D = PathP (λ i → U (p i)) A.fmap fmap
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-- eeq : (λ f → A.fmap f) ≡ fmap
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-- eeq = funExtImp (λ A → funExtImp (λ B → funExt (λ f → isofmap {A} {B} f)))
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-- where
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-- module _ {X : ℂ.Object} {Y : ℂ.Object} (f : ℂ [ X , Y ]) where
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-- isofmap : A.fmap f ≡ fmap f
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-- isofmap = {!ap!}
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d : D A.omap refl
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d = res
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where
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module _
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( fmap : U A.omap )
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( let
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raw-B : RawFunctor ℂ 𝔻
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raw-B = record { omap = A.omap ; fmap = fmap }
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)
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( isF-B' : IsFunctor ℂ 𝔻 raw-B )
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( let
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B' : Functor ℂ 𝔻
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B' = record { raw = raw-B ; isFunctor = isF-B' }
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)
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( iso' : A ≊ B' )
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where
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module _ {X Y : ℂ.Object} (f : ℂ [ X , Y ]) where
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step : {!!} 𝔻.≊ {!!}
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step = {!!}
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resres : A.fmap {X} {Y} f ≡ fmap {X} {Y} f
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resres = {!!}
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res : PathP (λ i → U A.omap) A.fmap fmap
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res i {X} {Y} f = resres f i
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fmapEq : PathP (λ i → U (omapEq i)) A.fmap B.fmap
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fmapEq = pathJ D d B.omap omapEq B.fmap B.isFunctor iso
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rawEq : A.raw ≡ B.raw
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rawEq i = record { omap = omapEq i ; fmap = fmapEq i }
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private
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f : (A ≡ B) → (A ≊ B)
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f p = idToNatTrans p , idToNatTrans (sym p) , NaturalTransformation≡ A A (funExt (λ C → {!!})) , {!!}
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g : (A ≊ B) → (A ≡ B)
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g = Functor≡ ∘ rawEq
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inv : AreInverses f g
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inv = {!funExt λ p → ?!} , {!!}
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iso : (A ≡ B) ≅ (A ≊ B)
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iso = f , g , inv
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univ : (A ≡ B) ≃ (A ≊ B)
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univ = fromIsomorphism _ _ iso
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-- There used to be some work-in-progress on this theorem, please go back to
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-- this point in time to see it:
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--
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-- commit 6b7d66b7fc936fe3674b2fd9fa790bd0e3fec12f
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-- Author: Frederik Hanghøj Iversen <fhi.1990@gmail.com>
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-- Date: Fri Apr 13 15:26:46 2018 +0200
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postulate univalent : Univalent
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univalent : Univalent
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univalent = univalenceFrom≃ univ
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isCategory : IsCategory raw
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IsCategory.isPreCategory isCategory = isPreCategory
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@ -8,7 +8,7 @@ open import Cat.Category
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open import Cat.Category.Functor
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open import Cat.Category.Product
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open import Cat.Wishlist
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open import Cat.Equivalence renaming (_≅_ to _≈_)
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open import Cat.Equivalence
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_⊙_ : {ℓa ℓb ℓc : Level} {A : Set ℓa} {B : Set ℓb} {C : Set ℓc} → (A ≃ B) → (B ≃ C) → A ≃ C
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eqA ⊙ eqB = Equivalence.compose eqA eqB
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@ -93,7 +93,7 @@ module _ (ℓ : Level) where
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re-ve e = refl
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inv : AreInverses (f {p} {q}) (g {p} {q})
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inv = funExt ve-re , funExt re-ve
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iso : (p ≡ q) ≈ (fst p ≡ fst q)
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iso : (p ≡ q) ≅ (fst p ≡ fst q)
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iso = f , g , inv
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module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
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@ -109,7 +109,7 @@ module _ (ℓ : Level) where
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re-ve = inverse-from-to-iso A B
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ve-re : (x : isIso f) → (obv ∘ inv) x ≡ x
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ve-re = inverse-to-from-iso A B sA sB
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iso : isEquiv A B f ≈ isIso f
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iso : isEquiv A B f ≅ isIso f
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iso = obv , inv , funExt re-ve , funExt ve-re
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in fromIsomorphism _ _ iso
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@ -125,7 +125,7 @@ module _ (ℓ : Level) where
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step2 : (hA ≡ hB) ≃ (A ≡ B)
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step2 = lem2 (λ A → isSetIsProp) hA hB
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univ≃ : (hA ≡ hB) ≃ (hA ≅ hB)
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univ≃ : (hA ≡ hB) ≃ (hA ≊ hB)
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univ≃ = step2 ⊙ univalence ⊙ step0
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univalent : Univalent
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@ -32,7 +32,6 @@ open import Cat.Prelude
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import Cat.Equivalence
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open Cat.Equivalence public using () renaming (Isomorphism to TypeIsomorphism)
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open Cat.Equivalence
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renaming (_≅_ to _≈_)
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hiding (preorder≅ ; Isomorphism)
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------------------
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@ -52,6 +51,8 @@ record RawCategory (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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identity : {A : Object} → Arrow A A
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_<<<_ : {A B C : Object} → Arrow B C → Arrow A B → Arrow A C
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-- infixr 8 _<<<_
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-- infixl 8 _>>>_
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infixl 10 _<<<_ _>>>_
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-- | Operations on data
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@ -86,8 +87,8 @@ record RawCategory (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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Isomorphism : ∀ {A B} → (f : Arrow A B) → Set ℓb
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Isomorphism {A} {B} f = Σ[ g ∈ Arrow B A ] IsInverseOf f g
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_≅_ : (A B : Object) → Set ℓb
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_≅_ A B = Σ[ f ∈ Arrow A B ] (Isomorphism f)
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_≊_ : (A B : Object) → Set ℓb
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_≊_ A B = Σ[ f ∈ Arrow A B ] (Isomorphism f)
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module _ {A B : Object} where
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Epimorphism : {X : Object } → (f : Arrow A B) → Set ℓb
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@ -111,29 +112,30 @@ record RawCategory (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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-- | Univalence is indexed by a raw category as well as an identity proof.
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module Univalence (isIdentity : IsIdentity identity) where
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-- | The identity isomorphism
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idIso : (A : Object) → A ≅ A
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idIso : (A : Object) → A ≊ A
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idIso A = identity , identity , isIdentity
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-- | Extract an isomorphism from an equality
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--
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-- [HoTT §9.1.4]
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idToIso : (A B : Object) → A ≡ B → A ≅ B
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idToIso A B eq = transp (\ i → A ≅ eq i) (idIso A)
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idToIso : (A B : Object) → A ≡ B → A ≊ B
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idToIso A B eq = transp (\ i → A ≊ eq i) (idIso A)
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Univalent : Set (ℓa ⊔ ℓb)
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Univalent = {A B : Object} → isEquiv (A ≡ B) (A ≅ B) (idToIso A B)
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Univalent = {A B : Object} → isEquiv (A ≡ B) (A ≊ B) (idToIso A B)
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univalenceFromIsomorphism : {A B : Object}
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→ TypeIsomorphism (idToIso A B) → isEquiv (A ≡ B) (A ≅ B) (idToIso A B)
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→ TypeIsomorphism (idToIso A B) → isEquiv (A ≡ B) (A ≊ B) (idToIso A B)
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univalenceFromIsomorphism = fromIso _ _
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-- A perhaps more readable version of univalence:
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Univalent≃ = {A B : Object} → (A ≡ B) ≃ (A ≅ B)
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Univalent≃ = {A B : Object} → (A ≡ B) ≃ (A ≊ B)
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Univalent≅ = {A B : Object} → (A ≡ B) ≅ (A ≊ B)
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private
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-- | Equivalent formulation of univalence.
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Univalent[Contr] : Set _
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Univalent[Contr] = ∀ A → isContr (Σ[ X ∈ Object ] A ≅ X)
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Univalent[Contr] = ∀ A → isContr (Σ[ X ∈ Object ] A ≊ X)
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-- From: Thierry Coquand <Thierry.Coquand@cse.gu.se>
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-- Date: Wed, Mar 21, 2018 at 3:12 PM
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@ -145,15 +147,18 @@ record RawCategory (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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univalenceFrom≃ = from[Contr] ∘ step
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where
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module _ (f : Univalent≃) (A : Object) where
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lem : Σ Object (A ≡_) ≃ Σ Object (A ≅_)
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lem : Σ Object (A ≡_) ≃ Σ Object (A ≊_)
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lem = equivSig λ _ → f
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aux : isContr (Σ Object (A ≡_))
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aux = (A , refl) , (λ y → contrSingl (snd y))
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step : isContr (Σ Object (A ≅_))
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step : isContr (Σ Object (A ≊_))
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step = equivPreservesNType {n = ⟨-2⟩} lem aux
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univalenceFrom≅ : Univalent≅ → Univalent
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univalenceFrom≅ x = univalenceFrom≃ $ fromIsomorphism _ _ x
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propUnivalent : isProp Univalent
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propUnivalent a b i = propPi (λ iso → propIsContr) a b i
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@ -263,8 +268,8 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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module _ where
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private
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trans≅ : Transitive _≅_
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trans≅ (f , f~ , f-inv) (g , g~ , g-inv)
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trans≊ : Transitive _≊_
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trans≊ (f , f~ , f-inv) (g , g~ , g-inv)
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= g <<< f
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, f~ <<< g~
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, ( begin
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@ -283,11 +288,11 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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g <<< g~ ≡⟨ snd g-inv ⟩
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identity ∎
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)
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isPreorder : IsPreorder _≅_
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isPreorder = record { isEquivalence = equalityIsEquivalence ; reflexive = idToIso _ _ ; trans = trans≅ }
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isPreorder : IsPreorder _≊_
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isPreorder = record { isEquivalence = equalityIsEquivalence ; reflexive = idToIso _ _ ; trans = trans≊ }
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preorder≅ : Preorder _ _ _
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preorder≅ = record { Carrier = Object ; _≈_ = _≡_ ; _∼_ = _≅_ ; isPreorder = isPreorder }
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preorder≊ : Preorder _ _ _
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preorder≊ = record { Carrier = Object ; _≈_ = _≡_ ; _∼_ = _≊_ ; isPreorder = isPreorder }
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record PreCategory : Set (lsuc (ℓa ⊔ ℓb)) where
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field
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@ -319,7 +324,7 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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iso : TypeIsomorphism (idToIso A B)
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iso = toIso _ _ univalent
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isoToId : (A ≅ B) → (A ≡ B)
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isoToId : (A ≊ B) → (A ≡ B)
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isoToId = fst iso
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asTypeIso : TypeIsomorphism (idToIso A B)
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@ -329,13 +334,46 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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inverse-from-to-iso' : AreInverses (idToIso A B) isoToId
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inverse-from-to-iso' = snd iso
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module _ {a b : Object} (f : Arrow a b) where
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module _ {a' : Object} (p : a ≡ a') where
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private
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p~ : Arrow a' a
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p~ = fst (snd (idToIso _ _ p))
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D : ∀ a'' → a ≡ a'' → Set _
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D a'' p' = coe (cong (λ x → Arrow x b) p') f ≡ f <<< (fst (snd (idToIso _ _ p')))
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9-1-9-left : coe (cong (λ x → Arrow x b) p) f ≡ f <<< p~
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9-1-9-left = pathJ D (begin
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coe refl f ≡⟨ id-coe ⟩
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f ≡⟨ sym rightIdentity ⟩
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f <<< identity ≡⟨ cong (f <<<_) (sym subst-neutral) ⟩
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f <<< _ ∎) a' p
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module _ {b' : Object} (p : b ≡ b') where
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private
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p* : Arrow b b'
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p* = fst (idToIso _ _ p)
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D : ∀ b'' → b ≡ b'' → Set _
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D b'' p' = coe (cong (λ x → Arrow a x) p') f ≡ fst (idToIso _ _ p') <<< f
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9-1-9-right : coe (cong (λ x → Arrow a x) p) f ≡ p* <<< f
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9-1-9-right = pathJ D (begin
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coe refl f ≡⟨ id-coe ⟩
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f ≡⟨ sym leftIdentity ⟩
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identity <<< f ≡⟨ cong (_<<< f) (sym subst-neutral) ⟩
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_ <<< f ∎) b' p
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-- lemma 9.1.9 in hott
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module _ {a a' b b' : Object}
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(p : a ≡ a') (q : b ≡ b') (f : Arrow a b)
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where
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private
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||||
q* : Arrow b b'
|
||||
q* = fst (idToIso b b' q)
|
||||
q* = fst (idToIso _ _ q)
|
||||
q~ : Arrow b' b
|
||||
q~ = fst (snd (idToIso _ _ q))
|
||||
p* : Arrow a a'
|
||||
p* = fst (idToIso _ _ p)
|
||||
p~ : Arrow a' a
|
||||
|
|
@ -376,7 +414,8 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
|
|||
where
|
||||
lem : p~ <<< p* ≡ identity
|
||||
lem = fst (snd (snd (idToIso _ _ p)))
|
||||
module _ {A B X : Object} (iso : A ≅ B) where
|
||||
|
||||
module _ {A B X : Object} (iso : A ≊ B) where
|
||||
private
|
||||
p : A ≡ B
|
||||
p = isoToId iso
|
||||
|
|
@ -384,7 +423,7 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
|
|||
p-dom = cong (λ x → Arrow x X) p
|
||||
p-cod : Arrow X A ≡ Arrow X B
|
||||
p-cod = cong (λ x → Arrow X x) p
|
||||
lem : ∀ {A B} {x : A ≅ B} → idToIso A B (isoToId x) ≡ x
|
||||
lem : ∀ {A B} {x : A ≊ B} → idToIso A B (isoToId x) ≡ x
|
||||
lem {x = x} i = snd inverse-from-to-iso' i x
|
||||
|
||||
open Σ iso renaming (fst to ι) using ()
|
||||
|
|
@ -459,7 +498,7 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
|
|||
left = Xprop _ _
|
||||
right : X→Y <<< Y→X ≡ identity
|
||||
right = Yprop _ _
|
||||
iso : X ≅ Y
|
||||
iso : X ≊ Y
|
||||
iso = X→Y , Y→X , left , right
|
||||
p0 : X ≡ Y
|
||||
p0 = isoToId iso
|
||||
|
|
@ -489,7 +528,7 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
|
|||
left = Yprop _ _
|
||||
right : X→Y <<< Y→X ≡ identity
|
||||
right = Xprop _ _
|
||||
iso : X ≅ Y
|
||||
iso : X ≊ Y
|
||||
iso = Y→X , X→Y , right , left
|
||||
res : Xi ≡ Yi
|
||||
res = lemSig propIsInitial _ _ (isoToId iso)
|
||||
|
|
@ -500,11 +539,11 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
|
|||
open import Data.Nat using (_≤_ ; z≤n ; s≤s)
|
||||
setIso : ∀ x → isSet (Isomorphism x)
|
||||
setIso x = ntypeCommulative ((s≤s {n = 1} z≤n)) (propIsomorphism x)
|
||||
step : isSet (A ≅ B)
|
||||
step : isSet (A ≊ B)
|
||||
step = setSig {sA = arrowsAreSets} {sB = setIso}
|
||||
res : isSet (A ≡ B)
|
||||
res = equivPreservesNType
|
||||
{A = A ≅ B} {B = A ≡ B} {n = ⟨0⟩}
|
||||
{A = A ≊ B} {B = A ≡ B} {n = ⟨0⟩}
|
||||
(Equivalence.symmetry (univalent≃ {A = A} {B}))
|
||||
step
|
||||
|
||||
|
|
@ -636,10 +675,10 @@ module Opposite {ℓa ℓb : Level} where
|
|||
→ a × b × c → b × a × c
|
||||
genericly (a , b , c) = (b , a , c)
|
||||
|
||||
shuffle : A ≅ B → A ℂ.≅ B
|
||||
shuffle : A ≊ B → A ℂ.≊ B
|
||||
shuffle (f , g , inv) = g , f , inv
|
||||
|
||||
shuffle~ : A ℂ.≅ B → A ≅ B
|
||||
shuffle~ : A ℂ.≊ B → A ≊ B
|
||||
shuffle~ (f , g , inv) = g , f , inv
|
||||
|
||||
-- Shouldn't be necessary to use `arrowsAreSets` here, but we have it,
|
||||
|
|
@ -656,12 +695,12 @@ module Opposite {ℓa ℓb : Level} where
|
|||
open Σ r-areInv renaming (fst to r-invs ; snd to r-iso)
|
||||
open Σ r-iso renaming (fst to r-l ; snd to r-r)
|
||||
|
||||
ζ : A ≅ B → A ≡ B
|
||||
ζ : A ≊ B → A ≡ B
|
||||
ζ = η ∘ shuffle
|
||||
|
||||
-- inv : AreInverses (ℂ.idToIso A B) f
|
||||
inv-ζ : AreInverses (idToIso A B) ζ
|
||||
-- recto-verso : ℂ.idToIso A B <<< f ≡ idFun (A ℂ.≅ B)
|
||||
-- recto-verso : ℂ.idToIso A B <<< f ≡ idFun (A ℂ.≊ B)
|
||||
inv-ζ = record
|
||||
{ fst = funExt (λ x → begin
|
||||
(ζ ∘ idToIso A B) x ≡⟨⟩
|
||||
|
|
|
|||
|
|
@ -204,11 +204,8 @@ module _ {ℓa ℓb : Level} (ℂ : Category ℓa ℓb) where
|
|||
|
||||
open import Cat.Equivalence
|
||||
|
||||
Monoidal≅Kleisli : M.Monad ≅ K.Monad
|
||||
Monoidal≅Kleisli = forth , back , funExt backeq , funExt fortheq
|
||||
|
||||
Monoidal≃Kleisli : M.Monad ≃ K.Monad
|
||||
Monoidal≃Kleisli = forth , eqv
|
||||
Monoidal≊Kleisli : M.Monad ≅ K.Monad
|
||||
Monoidal≊Kleisli = forth , back , funExt backeq , funExt fortheq
|
||||
|
||||
Monoidal≡Kleisli : M.Monad ≡ K.Monad
|
||||
Monoidal≡Kleisli = ua (forth , eqv)
|
||||
Monoidal≡Kleisli = isoToPath Monoidal≊Kleisli
|
||||
|
|
|
|||
|
|
@ -123,7 +123,7 @@ module voe {ℓa ℓb : Level} (ℂ : Category ℓa ℓb) where
|
|||
-- | to talk about voevodsky's construction.
|
||||
module _ (omap : Omap ℂ ℂ) (pure : {X : Object} → Arrow X (omap X)) where
|
||||
private
|
||||
module E = AreInverses {f = (fst (Monoidal≅Kleisli ℂ))} {fst (snd (Monoidal≅Kleisli ℂ))}(Monoidal≅Kleisli ℂ .snd .snd)
|
||||
module E = AreInverses {f = (fst (Monoidal≊Kleisli ℂ))} {fst (snd (Monoidal≊Kleisli ℂ))}(Monoidal≊Kleisli ℂ .snd .snd)
|
||||
|
||||
Monoidal→Kleisli : M.Monad → K.Monad
|
||||
Monoidal→Kleisli = E.obverse
|
||||
|
|
|
|||
|
|
@ -2,7 +2,7 @@
|
|||
module Cat.Category.Product where
|
||||
|
||||
open import Cat.Prelude as P hiding (_×_ ; fst ; snd)
|
||||
open import Cat.Equivalence hiding (_≅_)
|
||||
open import Cat.Equivalence
|
||||
|
||||
open import Cat.Category
|
||||
|
||||
|
|
@ -176,10 +176,10 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
open Σ x renaming (fst to xa ; snd to xb)
|
||||
open Σ 𝕐 renaming (fst to Y ; snd to y)
|
||||
open Σ y renaming (fst to ya ; snd to yb)
|
||||
open import Cat.Equivalence using (composeIso) renaming (_≅_ to _≈_)
|
||||
open import Cat.Equivalence using (composeIso) renaming (_≅_ to _≅_)
|
||||
step0
|
||||
: ((X , xa , xb) ≡ (Y , ya , yb))
|
||||
≈ (Σ[ p ∈ (X ≡ Y) ] (PathP (λ i → ℂ.Arrow (p i) A) xa ya) × (PathP (λ i → ℂ.Arrow (p i) B) xb yb))
|
||||
≅ (Σ[ p ∈ (X ≡ Y) ] (PathP (λ i → ℂ.Arrow (p i) A) xa ya) × (PathP (λ i → ℂ.Arrow (p i) B) xb yb))
|
||||
step0
|
||||
= (λ p → cong fst p , cong-d (fst ∘ snd) p , cong-d (snd ∘ snd) p)
|
||||
-- , (λ x → λ i → fst x i , (fst (snd x) i) , (snd (snd x) i))
|
||||
|
|
@ -190,7 +190,7 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
-- Should follow from c being univalent
|
||||
iso-id-inv : {p : X ≡ Y} → p ≡ ℂ.isoToId (ℂ.idToIso X Y p)
|
||||
iso-id-inv {p} = sym (λ i → fst (ℂ.inverse-from-to-iso' {X} {Y}) i p)
|
||||
id-iso-inv : {iso : X ℂ.≅ Y} → iso ≡ ℂ.idToIso X Y (ℂ.isoToId iso)
|
||||
id-iso-inv : {iso : X ℂ.≊ Y} → iso ≡ ℂ.idToIso X Y (ℂ.isoToId iso)
|
||||
id-iso-inv {iso} = sym (λ i → snd (ℂ.inverse-from-to-iso' {X} {Y}) i iso)
|
||||
|
||||
lemA : {A B : Object} {f g : Arrow A B} → fst f ≡ fst g → f ≡ g
|
||||
|
|
@ -207,7 +207,7 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
|
||||
step1
|
||||
: (Σ[ p ∈ (X ≡ Y) ] (PathP (λ i → ℂ.Arrow (p i) A) xa ya) × (PathP (λ i → ℂ.Arrow (p i) B) xb yb))
|
||||
≈ Σ (X ℂ.≅ Y) (λ iso
|
||||
≅ Σ (X ℂ.≊ Y) (λ iso
|
||||
→ let p = ℂ.isoToId iso
|
||||
in
|
||||
( PathP (λ i → ℂ.Arrow (p i) A) xa ya)
|
||||
|
|
@ -216,7 +216,7 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
step1
|
||||
= symIso
|
||||
(isoSigFst
|
||||
{A = (X ℂ.≅ Y)}
|
||||
{A = (X ℂ.≊ Y)}
|
||||
{B = (X ≡ Y)}
|
||||
(ℂ.groupoidObject _ _)
|
||||
{Q = \ p → (PathP (λ i → ℂ.Arrow (p i) A) xa ya) × (PathP (λ i → ℂ.Arrow (p i) B) xb yb)}
|
||||
|
|
@ -225,13 +225,13 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
)
|
||||
|
||||
step2
|
||||
: Σ (X ℂ.≅ Y) (λ iso
|
||||
: Σ (X ℂ.≊ Y) (λ iso
|
||||
→ let p = ℂ.isoToId iso
|
||||
in
|
||||
( PathP (λ i → ℂ.Arrow (p i) A) xa ya)
|
||||
× PathP (λ i → ℂ.Arrow (p i) B) xb yb
|
||||
)
|
||||
≈ ((X , xa , xb) ≅ (Y , ya , yb))
|
||||
≅ ((X , xa , xb) ≊ (Y , ya , yb))
|
||||
step2
|
||||
= ( λ{ (iso@(f , f~ , inv-f) , p , q)
|
||||
→ ( f , sym (ℂ.domain-twist0 iso p) , sym (ℂ.domain-twist0 iso q))
|
||||
|
|
@ -242,7 +242,7 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
)
|
||||
, (λ{ (f , f~ , inv-f , inv-f~) →
|
||||
let
|
||||
iso : X ℂ.≅ Y
|
||||
iso : X ℂ.≊ Y
|
||||
iso = fst f , fst f~ , cong fst inv-f , cong fst inv-f~
|
||||
p : X ≡ Y
|
||||
p = ℂ.isoToId iso
|
||||
|
|
@ -275,14 +275,14 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
|
|||
-- must compose to give idToIso
|
||||
iso
|
||||
: ((X , xa , xb) ≡ (Y , ya , yb))
|
||||
≈ ((X , xa , xb) ≅ (Y , ya , yb))
|
||||
≅ ((X , xa , xb) ≊ (Y , ya , yb))
|
||||
iso = step0 ⊙ step1 ⊙ step2
|
||||
where
|
||||
infixl 5 _⊙_
|
||||
_⊙_ = composeIso
|
||||
equiv1
|
||||
: ((X , xa , xb) ≡ (Y , ya , yb))
|
||||
≃ ((X , xa , xb) ≅ (Y , ya , yb))
|
||||
≃ ((X , xa , xb) ≊ (Y , ya , yb))
|
||||
equiv1 = _ , fromIso _ _ (snd iso)
|
||||
|
||||
univalent : Univalent
|
||||
|
|
|
|||
|
|
@ -5,7 +5,7 @@ open import Cubical.Primitives
|
|||
open import Cubical.FromStdLib renaming (ℓ-max to _⊔_)
|
||||
open import Cubical.PathPrelude hiding (inverse)
|
||||
open import Cubical.PathPrelude using (isEquiv ; isContr ; fiber) public
|
||||
open import Cubical.GradLemma
|
||||
open import Cubical.GradLemma hiding (isoToPath)
|
||||
|
||||
open import Cat.Prelude using (lemPropF ; setPi ; lemSig ; propSet ; Preorder ; equalityIsEquivalence ; propSig ; id-coe)
|
||||
|
||||
|
|
@ -329,6 +329,9 @@ preorder≅ ℓ = record
|
|||
|
||||
|
||||
module _ {ℓ : Level} {A B : Set ℓ} where
|
||||
isoToPath : (A ≅ B) → (A ≡ B)
|
||||
isoToPath = ua ∘ fromIsomorphism _ _
|
||||
|
||||
univalence : (A ≡ B) ≃ (A ≃ B)
|
||||
univalence = Equivalence.compose u' aux
|
||||
where
|
||||
|
|
|
|||
|
|
@ -90,6 +90,7 @@ IsPreorder
|
|||
IsPreorder _~_ = Relation.Binary.IsPreorder _≡_ _~_
|
||||
|
||||
module _ {ℓ : Level} {A : Set ℓ} {a : A} where
|
||||
-- FIXME rename to `coe-neutral`
|
||||
id-coe : coe refl a ≡ a
|
||||
id-coe = begin
|
||||
coe refl a ≡⟨⟩
|
||||
|
|
|
|||
Loading…
Reference in a new issue