Use a single version of \simeq
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@ -33,9 +33,6 @@ module _ (ℓa ℓb : Level) where
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isIdentity : IsIdentity λ { {A} → identity {A} }
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isIdentity = (Σ≡ refl refl) , Σ≡ refl refl
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open import Cubical.NType.Properties
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open import Cubical.Sigma
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isPreCategory : IsPreCategory RawFam
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IsPreCategory.isAssociative isPreCategory
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{A} {B} {C} {D} {f} {g} {h} = isAssociative {A} {B} {C} {D} {f} {g} {h}
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@ -78,7 +78,6 @@ module Fun {ℓc ℓc' ℓd ℓd' : Level} (ℂ : Category ℓc ℓc') (𝔻 : C
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F[ F ∘ G~ ] ≡⟨ prop1 ⟩
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idFunctor ∎
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open import Cubical.Univalence
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p0 : F ≡ G
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p0 = begin
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F ≡⟨ sym Functors.rightIdentity ⟩
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@ -2,21 +2,15 @@
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{-# OPTIONS --allow-unsolved-metas --cubical --caching #-}
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module Cat.Categories.Sets where
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open import Cat.Prelude as P hiding (_≃_)
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open import Cat.Prelude as P
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open import Function using (_∘_ ; _∘′_)
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open import Cubical.Univalence using (univalence ; con ; _≃_ ; idtoeqv ; ua)
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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 as Eqv using (AreInverses ; module Equiv≃ ; module NoEta)
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open NoEta
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module Equivalence = Equivalence′
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open import Cat.Equivalence renaming (_≅_ to _≈_)
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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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@ -52,7 +46,7 @@ module _ (ℓ : Level) where
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open IsPreCategory isPreCat hiding (_∘_)
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isIso = Eqv.Isomorphism
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isIso = TypeIsomorphism
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module _ {hA hB : hSet ℓ} where
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open Σ hA renaming (fst to A ; snd to sA)
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open Σ hB renaming (fst to B ; snd to sB)
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@ -95,7 +89,7 @@ module _ (ℓ : Level) where
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module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
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lem2 : ((x : A) → isProp (P x)) → (p q : Σ A P)
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→ (p ≡ q) ≃ (fst p ≡ fst q)
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lem2 pA p q = fromIsomorphism iso
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lem2 pA p q = fromIsomorphism _ _ iso
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where
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f : ∀ {p q} → p ≡ q → fst p ≡ fst q
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f e i = fst (e i)
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@ -111,7 +105,7 @@ module _ (ℓ : Level) where
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{ verso-recto = funExt ve-re
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; recto-verso = funExt re-ve
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}
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iso : (p ≡ q) Eqv.≅ (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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lem3 : ∀ {ℓc} {Q : A → Set (ℓc ⊔ ℓb)}
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@ -119,12 +113,12 @@ module _ (ℓ : Level) where
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lem3 {Q = Q} eA = res
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where
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f : Σ A P → Σ A Q
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f (a , pA) = a , _≃_.eqv (eA a) pA
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f (a , pA) = a , fst (eA a) pA
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g : Σ A Q → Σ A P
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g (a , qA) = a , g' qA
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where
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k : Eqv.Isomorphism _
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k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
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k : TypeIsomorphism _
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k = toIso _ _ (snd (eA a))
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open Σ k renaming (fst to g')
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ve-re : (x : Σ A P) → (g ∘ f) x ≡ x
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ve-re x i = fst x , eq i
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@ -133,16 +127,16 @@ module _ (ℓ : Level) where
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eq = begin
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snd ((g ∘ f) x) ≡⟨⟩
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snd (g (f (a , pA))) ≡⟨⟩
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g' (_≃_.eqv (eA a) pA) ≡⟨ lem ⟩
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g' (fst (eA a) pA) ≡⟨ lem ⟩
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pA ∎
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where
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open Σ x renaming (fst to a ; snd to pA)
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k : Eqv.Isomorphism _
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k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
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k : TypeIsomorphism _
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k = toIso _ _ (snd (eA a))
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open Σ k renaming (fst to g' ; snd to inv)
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module A = AreInverses inv
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-- anti-funExt
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lem : (g' ∘ (_≃_.eqv (eA a))) pA ≡ pA
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lem : (g' ∘ (fst (eA a))) pA ≡ pA
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lem i = A.verso-recto i pA
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re-ve : (x : Σ A Q) → (f ∘ g) x ≡ x
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re-ve x i = fst x , eq i
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@ -150,11 +144,11 @@ module _ (ℓ : Level) where
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open Σ x renaming (fst to a ; snd to qA)
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eq = begin
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snd ((f ∘ g) x) ≡⟨⟩
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_≃_.eqv (eA a) (g' qA) ≡⟨ (λ i → A.recto-verso i qA) ⟩
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fst (eA a) (g' qA) ≡⟨ (λ i → A.recto-verso i qA) ⟩
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qA ∎
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where
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k : Eqv.Isomorphism _
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k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
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k : TypeIsomorphism _
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k = toIso _ _ (snd (eA a))
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open Σ k renaming (fst to g' ; snd to inv)
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module A = AreInverses inv
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inv : AreInverses f g
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@ -162,10 +156,10 @@ module _ (ℓ : Level) where
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{ verso-recto = funExt ve-re
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; recto-verso = funExt re-ve
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}
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iso : Σ A P Eqv.≅ Σ A Q
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iso : Σ A P ≈ Σ A Q
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iso = f , g , inv
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res : Σ A P ≃ Σ A Q
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res = fromIsomorphism iso
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res = fromIsomorphism _ _ iso
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module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
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lem4 : isSet A → isSet B → (f : A → B)
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@ -173,20 +167,20 @@ module _ (ℓ : Level) where
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lem4 sA sB f =
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let
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obv : isEquiv A B f → isIso f
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obv = Equiv≃.toIso A B
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obv = toIso A B
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inv : isIso f → isEquiv A B f
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inv = Equiv≃.fromIso A B
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inv = fromIso A B
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re-ve : (x : isEquiv A B f) → (inv ∘ obv) x ≡ x
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re-ve = Equiv≃.inverse-from-to-iso A B
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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 = Equiv≃.inverse-to-from-iso A B sA sB
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iso : isEquiv A B f Eqv.≅ isIso f
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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 = obv , inv ,
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record
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{ verso-recto = funExt re-ve
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; recto-verso = funExt ve-re
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}
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in fromIsomorphism iso
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in fromIsomorphism _ _ iso
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module _ {hA hB : Object} where
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open Σ hA renaming (fst to A ; snd to sA)
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@ -198,33 +192,15 @@ module _ (ℓ : Level) where
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-- univalence
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step1 : Σ (A → B) (isEquiv A B) ≃ (A ≡ B)
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step1 = hh ⊙ h
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where
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h : (A ≃ B) ≃ (A ≡ B)
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h = sym≃ (univalence {A = A} {B})
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obv : Σ (A → B) (isEquiv A B) → A ≃ B
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obv = Eqv.deEta
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inv : A ≃ B → Σ (A → B) (isEquiv A B)
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inv = Eqv.doEta
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re-ve : (x : _) → (inv ∘ obv) x ≡ x
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re-ve x = refl
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-- Because _≃_ does not have eta equality!
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ve-re : (x : _) → (obv ∘ inv) x ≡ x
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ve-re (con eqv isEqv) i = con eqv isEqv
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areInv : AreInverses obv inv
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areInv = record { verso-recto = funExt re-ve ; recto-verso = funExt ve-re }
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eqv : Σ (A → B) (isEquiv A B) Eqv.≅ (A ≃ B)
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eqv = obv , inv , areInv
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hh : Σ (A → B) (isEquiv A B) ≃ (A ≃ B)
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hh = fromIsomorphism eqv
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step1 = sym≃ univalence
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-- lem2 with propIsSet
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step2 : (A ≡ B) ≃ (hA ≡ hB)
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step2 = sym≃ (lem2 (λ A → isSetIsProp) hA hB)
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-- Go from an isomorphism on sets to an isomorphism on homotopic sets
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trivial? : (hA ≅ hB) ≃ (A Eqv.≅ B)
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trivial? = sym≃ (fromIsomorphism res)
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trivial? : (hA ≅ hB) ≃ (A ≈ B)
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trivial? = sym≃ (fromIsomorphism _ _ res)
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where
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fwd : Σ (A → B) isIso → hA ≅ hB
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fwd (f , g , inv) = f , g , inv.toPair
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@ -232,7 +208,7 @@ module _ (ℓ : Level) where
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module inv = AreInverses inv
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bwd : hA ≅ hB → Σ (A → B) isIso
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bwd (f , g , x , y) = f , g , record { verso-recto = x ; recto-verso = y }
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res : Σ (A → B) isIso Eqv.≅ (hA ≅ hB)
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res : Σ (A → B) isIso ≈ (hA ≅ hB)
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res = fwd , bwd , record { verso-recto = refl ; recto-verso = refl }
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conclusion : (hA ≅ hB) ≃ (hA ≡ hB)
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@ -274,7 +250,6 @@ module _ {ℓ : Level} where
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private
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𝓢 = 𝓢𝓮𝓽 ℓ
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open Category 𝓢
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open import Cubical.Sigma
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module _ (hA hB : Object) where
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open Σ hA renaming (fst to A ; snd to sA)
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@ -29,6 +29,7 @@
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module Cat.Category where
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open import Cat.Prelude
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open import Cat.Equivalence as Equivalence renaming (_≅_ to _≈_ ; Isomorphism to TypeIsomorphism) hiding (preorder≅)
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import Function
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@ -122,8 +123,6 @@ record RawCategory (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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import Cat.Equivalence as E
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open E public using () renaming (Isomorphism to TypeIsomorphism)
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open E using (module Equiv≃)
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open Equiv≃ using (fromIso)
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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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@ -299,10 +298,8 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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univalent≃ = _ , univalent
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module _ {A B : Object} where
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open import Cat.Equivalence using (module Equiv≃)
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iso-to-id : (A ≅ B) → (A ≡ B)
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iso-to-id = fst (Equiv≃.toIso _ _ univalent)
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iso-to-id = fst (toIso _ _ univalent)
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-- | All projections are propositions.
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module Propositionality where
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@ -321,7 +318,6 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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open Σ Yt renaming (fst to Y ; snd to Yit)
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open Σ (Xit {Y}) renaming (fst to Y→X) using ()
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open Σ (Yit {X}) renaming (fst to X→Y) using ()
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open import Cat.Equivalence hiding (_≅_)
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-- Need to show `left` and `right`, what we know is that the arrows are
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-- unique. Well, I know that if I compose these two arrows they must give
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-- the identity, since also the identity is the unique such arrow (by X
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@ -336,10 +332,10 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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right = Yprop _ _
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iso : X ≅ Y
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iso = X→Y , Y→X , left , right
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fromIso : X ≅ Y → X ≡ Y
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fromIso = fst (Equiv≃.toIso (X ≡ Y) (X ≅ Y) univalent)
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fromIso' : X ≅ Y → X ≡ Y
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fromIso' = fst (toIso (X ≡ Y) (X ≅ Y) univalent)
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p0 : X ≡ Y
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p0 = fromIso iso
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p0 = fromIso' iso
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p1 : (λ i → IsTerminal (p0 i)) [ Xit ≡ Yit ]
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p1 = lemPropF propIsTerminal p0
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res : Xt ≡ Yt
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@ -354,7 +350,6 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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open Σ Yi renaming (fst to Y ; snd to Yii)
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open Σ (Xii {Y}) renaming (fst to Y→X) using ()
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open Σ (Yii {X}) renaming (fst to X→Y) using ()
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open import Cat.Equivalence hiding (_≅_)
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-- Need to show `left` and `right`, what we know is that the arrows are
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-- unique. Well, I know that if I compose these two arrows they must give
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-- the identity, since also the identity is the unique such arrow (by X
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@ -369,10 +364,10 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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right = Xprop _ _
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iso : X ≅ Y
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iso = Y→X , X→Y , right , left
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fromIso : X ≅ Y → X ≡ Y
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fromIso = fst (Equiv≃.toIso (X ≡ Y) (X ≅ Y) univalent)
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fromIso' : X ≅ Y → X ≡ Y
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fromIso' = fst (toIso (X ≡ Y) (X ≅ Y) univalent)
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p0 : X ≡ Y
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p0 = fromIso iso
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p0 = fromIso' iso
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p1 : (λ i → IsInitial (p0 i)) [ Xii ≡ Yii ]
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p1 = lemPropF propIsInitial p0
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res : Xi ≡ Yi
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@ -436,9 +431,12 @@ module _ {ℓa ℓb : Level} (ℂ : RawCategory ℓa ℓb) where
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propIsCategory : isProp (IsCategory ℂ)
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propIsCategory = done
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-- | Univalent categories
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--
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-- Just bundles up the data with witnesses inhabiting the propositions.
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-- Question: Should I remove the type `Category`?
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record Category (ℓa ℓb : Level) : Set (lsuc (ℓa ⊔ ℓb)) where
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field
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raw : RawCategory ℓa ℓb
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@ -459,10 +457,8 @@ module _ {ℓa ℓb : Level} {ℂ 𝔻 : Category ℓa ℓb} where
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isCategoryEq = lemPropF propIsCategory rawEq
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Category≡ : ℂ ≡ 𝔻
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Category≡ i = record
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{ raw = rawEq i
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; isCategory = isCategoryEq i
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}
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Category.raw (Category≡ i) = rawEq i
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Category.isCategory (Category≡ i) = isCategoryEq i
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-- | Syntax for arrows- and composition in a given category.
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module _ {ℓa ℓb : Level} (ℂ : Category ℓa ℓb) where
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@ -501,9 +497,8 @@ module Opposite {ℓa ℓb : Level} where
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open IsPreCategory isPreCategory
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module _ {A B : ℂ.Object} where
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open import Cat.Equivalence as Equivalence hiding (_≅_)
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k : Equivalence.Isomorphism (ℂ.idToIso A B)
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k = Equiv≃.toIso _ _ ℂ.univalent
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k = toIso _ _ ℂ.univalent
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open Σ k renaming (fst to f ; snd to inv)
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open AreInverses inv
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@ -568,7 +563,7 @@ module Opposite {ℓa ℓb : Level} where
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h = ff , invv
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univalent : isEquiv (A ≡ B) (A ≅ B)
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(Univalence.idToIso (swap ℂ.isIdentity) A B)
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univalent = Equiv≃.fromIso _ _ h
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univalent = fromIso _ _ h
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isCategory : IsCategory opRaw
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IsCategory.isPreCategory isCategory = isPreCategory
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@ -5,7 +5,6 @@ open import Cat.Prelude
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open import Function
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open import Cubical
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open import Cubical.NType.Properties using (lemPropF)
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open import Cat.Category
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@ -1,8 +1,8 @@
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{-# OPTIONS --allow-unsolved-metas --cubical #-}
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module Cat.Category.Product where
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open import Cubical.NType.Properties
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open import Cat.Prelude as P hiding (_×_ ; fst ; snd)
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open import Cat.Equivalence hiding (_≅_)
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-- module P = Cat.Prelude
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open import Cat.Category
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@ -285,10 +285,8 @@ module Try0 {ℓa ℓb : Level} {ℂ : Category ℓa ℓb}
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open Category cat
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open import Cat.Equivalence
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lemma : Terminal ≃ Product ℂ A B
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lemma = Equiv≃.fromIsomorphism Terminal (Product ℂ A B) (f , g , inv)
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lemma = fromIsomorphism Terminal (Product ℂ A B) (f , g , inv)
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where
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f : Terminal → Product ℂ A B
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f ((X , x0 , x1) , uniq) = p
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@ -3,11 +3,26 @@ module Cat.Equivalence where
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open import Cubical.Primitives
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open import Cubical.FromStdLib renaming (ℓ-max to _⊔_)
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-- FIXME: Don't hide ≃
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open import Cubical.PathPrelude hiding (inverse ; _≃_)
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||||
open import Cubical.PathPrelude using (isEquiv ; isContr ; fiber) public
|
||||
open import Cubical.GradLemma
|
||||
|
||||
open import Cat.Prelude using (lemPropF ; setPi ; lemSig ; propSet ; Preorder ; equalityIsEquivalence)
|
||||
open import Cat.Prelude using (lemPropF ; setPi ; lemSig ; propSet ; Preorder ; equalityIsEquivalence ; _≃_)
|
||||
|
||||
import Cubical.Univalence as U
|
||||
|
||||
module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
||||
open Cubical.PathPrelude
|
||||
deEta : A ≃ B → A U.≃ B
|
||||
deEta (a , b) = U.con a b
|
||||
doEta : A U.≃ B → A ≃ B
|
||||
doEta (U.con eqv isEqv) = eqv , isEqv
|
||||
|
||||
module _ {ℓ : Level} {A B : Set ℓ} where
|
||||
open Cubical.PathPrelude
|
||||
ua : A ≃ B → A ≡ B
|
||||
ua (f , isEqv) = U.ua (U.con f isEqv)
|
||||
|
||||
module _ {ℓa ℓb : Level} where
|
||||
private
|
||||
|
@ -242,8 +257,7 @@ module _ {ℓa ℓb : Level} (A : Set ℓa) (B : Set ℓb) where
|
|||
where
|
||||
import Cubical.NType.Properties as P
|
||||
|
||||
module Equiv≃ where
|
||||
open Equiv ≃isEquiv public
|
||||
open Equiv ≃isEquiv public
|
||||
|
||||
module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
||||
open Cubical.PathPrelude using (_≃_)
|
||||
|
@ -273,20 +287,19 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
|||
}
|
||||
|
||||
composeIsEquiv : isEquiv A B f → isEquiv B C g → isEquiv A C (g ∘ f)
|
||||
composeIsEquiv a b = Equiv≃.fromIso A C (composeIsomorphism a' b')
|
||||
composeIsEquiv a b = fromIso A C (composeIsomorphism a' b')
|
||||
where
|
||||
a' = Equiv≃.toIso A B a
|
||||
b' = Equiv≃.toIso B C b
|
||||
a' = toIso A B a
|
||||
b' = toIso B C b
|
||||
|
||||
composeIso : {ℓc : Level} {C : Set ℓc} → (A ≅ B) → (B ≅ C) → A ≅ C
|
||||
composeIso {C = C} (f , iso-f) (g , iso-g) = g ∘ f , composeIsomorphism iso-f iso-g
|
||||
|
||||
-- Gives the quasi inverse from an equivalence.
|
||||
module Equivalence (e : A ≃ B) where
|
||||
open Equiv≃ A B public
|
||||
private
|
||||
iso : Isomorphism (fst e)
|
||||
iso = snd (toIsomorphism e)
|
||||
iso = snd (toIsomorphism _ _ e)
|
||||
|
||||
open AreInverses (snd iso) public
|
||||
|
||||
|
@ -303,9 +316,7 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
|||
}
|
||||
|
||||
symmetry : B ≃ A
|
||||
symmetry = B≃A.fromIsomorphism symmetryIso
|
||||
where
|
||||
module B≃A = Equiv≃ B A
|
||||
symmetry = fromIsomorphism _ _ symmetryIso
|
||||
|
||||
preorder≅ : (ℓ : Level) → Preorder _ _ _
|
||||
preorder≅ ℓ = record
|
||||
|
@ -323,54 +334,24 @@ preorder≅ ℓ = record
|
|||
; trans = composeIso
|
||||
}
|
||||
}
|
||||
|
||||
module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
||||
open import Cubical.PathPrelude renaming (_≃_ to _≃η_)
|
||||
open import Cubical.Univalence using (_≃_)
|
||||
|
||||
doEta : A ≃ B → A ≃η B
|
||||
doEta (_≃_.con eqv isEqv) = eqv , isEqv
|
||||
|
||||
deEta : A ≃η B → A ≃ B
|
||||
deEta (eqv , isEqv) = _≃_.con eqv isEqv
|
||||
|
||||
module NoEta {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
||||
open import Cubical.PathPrelude renaming (_≃_ to _≃η_)
|
||||
open import Cubical.Univalence using (_≃_)
|
||||
|
||||
module Equivalence′ (e : A ≃ B) where
|
||||
open Equivalence (doEta e) hiding
|
||||
( toIsomorphism ; fromIsomorphism ; _~_
|
||||
; compose ; symmetryIso ; symmetry ) public
|
||||
|
||||
compose : {ℓc : Level} {C : Set ℓc} → (B ≃ C) → A ≃ C
|
||||
compose ee = deEta (Equivalence.compose (doEta e) (doEta ee))
|
||||
|
||||
symmetry : B ≃ A
|
||||
symmetry = deEta (Equivalence.symmetry (doEta e))
|
||||
|
||||
-- fromIso : {f : A → B} → Isomorphism f → isEquiv f
|
||||
-- fromIso = ?
|
||||
|
||||
-- toIso : {f : A → B} → isEquiv f → Isomorphism f
|
||||
-- toIso = ?
|
||||
|
||||
fromIsomorphism : A ≅ B → A ≃ B
|
||||
fromIsomorphism (f , iso) = _≃_.con f (Equiv≃.fromIso _ _ iso)
|
||||
|
||||
toIsomorphism : A ≃ B → A ≅ B
|
||||
toIsomorphism (_≃_.con f eqv) = f , Equiv≃.toIso _ _ eqv
|
||||
module _ {ℓ : Level} {A B : Set ℓ} where
|
||||
univalence : (A ≡ B) ≃ (A ≃ B)
|
||||
univalence = Equivalence.compose u' aux
|
||||
where
|
||||
u : (A ≡ B) U.≃ (A U.≃ B)
|
||||
u = U.univalence
|
||||
u' : (A ≡ B) ≃ (A U.≃ B)
|
||||
u' = doEta u
|
||||
aux : (A U.≃ B) ≃ (A ≃ B)
|
||||
aux = fromIsomorphism _ _ (doEta , deEta , record { verso-recto = funExt (λ{ (U.con _ _) → refl}) ; recto-verso = refl })
|
||||
|
||||
-- A few results that I have not generalized to work with both the eta and no-eta variable of ≃
|
||||
module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
|
||||
open NoEta
|
||||
open import Cubical.Univalence using (_≃_)
|
||||
|
||||
-- Equality on sigma's whose second component is a proposition is equivalent
|
||||
-- to equality on their first components.
|
||||
equivPropSig : ((x : A) → isProp (P x)) → (p q : Σ A P)
|
||||
→ (p ≡ q) ≃ (fst p ≡ fst q)
|
||||
equivPropSig pA p q = fromIsomorphism iso
|
||||
equivPropSig pA p q = fromIsomorphism _ _ iso
|
||||
where
|
||||
f : ∀ {p q} → p ≡ q → fst p ≡ fst q
|
||||
f e i = fst (e i)
|
||||
|
@ -396,12 +377,12 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
|
|||
equivSigSnd {Q = Q} eA = res
|
||||
where
|
||||
f : Σ A P → Σ A Q
|
||||
f (a , pA) = a , _≃_.eqv (eA a) pA
|
||||
f (a , pA) = a , fst (eA a) pA
|
||||
g : Σ A Q → Σ A P
|
||||
g (a , qA) = a , g' qA
|
||||
where
|
||||
k : Isomorphism _
|
||||
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
|
||||
k = toIso _ _ (snd (eA a))
|
||||
open Σ k renaming (fst to g')
|
||||
ve-re : (x : Σ A P) → (g ∘ f) x ≡ x
|
||||
ve-re x i = fst x , eq i
|
||||
|
@ -410,16 +391,16 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
|
|||
eq = begin
|
||||
snd ((g ∘ f) x) ≡⟨⟩
|
||||
snd (g (f (a , pA))) ≡⟨⟩
|
||||
g' (_≃_.eqv (eA a) pA) ≡⟨ lem ⟩
|
||||
g' (fst (eA a) pA) ≡⟨ lem ⟩
|
||||
pA ∎
|
||||
where
|
||||
open Σ x renaming (fst to a ; snd to pA)
|
||||
k : Isomorphism _
|
||||
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
|
||||
k = toIso _ _ (snd (eA a))
|
||||
open Σ k renaming (fst to g' ; snd to inv)
|
||||
module A = AreInverses inv
|
||||
-- anti-funExt
|
||||
lem : (g' ∘ (_≃_.eqv (eA a))) pA ≡ pA
|
||||
lem : (g' ∘ (fst (eA a))) pA ≡ pA
|
||||
lem i = A.verso-recto i pA
|
||||
re-ve : (x : Σ A Q) → (f ∘ g) x ≡ x
|
||||
re-ve x i = fst x , eq i
|
||||
|
@ -427,11 +408,11 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
|
|||
open Σ x renaming (fst to a ; snd to qA)
|
||||
eq = begin
|
||||
snd ((f ∘ g) x) ≡⟨⟩
|
||||
_≃_.eqv (eA a) (g' qA) ≡⟨ (λ i → A.recto-verso i qA) ⟩
|
||||
fst (eA a) (g' qA) ≡⟨ (λ i → A.recto-verso i qA) ⟩
|
||||
qA ∎
|
||||
where
|
||||
k : Isomorphism _
|
||||
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
|
||||
k = toIso _ _ (snd (eA a))
|
||||
open Σ k renaming (fst to g' ; snd to inv)
|
||||
module A = AreInverses inv
|
||||
inv : AreInverses f g
|
||||
|
@ -442,11 +423,9 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {P : A → Set ℓb} where
|
|||
iso : Σ A P ≅ Σ A Q
|
||||
iso = f , g , inv
|
||||
res : Σ A P ≃ Σ A Q
|
||||
res = fromIsomorphism iso
|
||||
res = fromIsomorphism _ _ iso
|
||||
|
||||
module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
||||
open NoEta
|
||||
open import Cubical.Univalence using (_≃_)
|
||||
-- Equivalence is equivalent to isomorphism when the domain and codomain of
|
||||
-- the equivalence is a set.
|
||||
equivSetIso : isSet A → isSet B → (f : A → B)
|
||||
|
@ -454,17 +433,17 @@ module _ {ℓa ℓb : Level} {A : Set ℓa} {B : Set ℓb} where
|
|||
equivSetIso sA sB f =
|
||||
let
|
||||
obv : isEquiv A B f → Isomorphism f
|
||||
obv = Equiv≃.toIso A B
|
||||
obv = toIso A B
|
||||
inv : Isomorphism f → isEquiv A B f
|
||||
inv = Equiv≃.fromIso A B
|
||||
inv = fromIso A B
|
||||
re-ve : (x : isEquiv A B f) → (inv ∘ obv) x ≡ x
|
||||
re-ve = Equiv≃.inverse-from-to-iso A B
|
||||
re-ve = inverse-from-to-iso A B
|
||||
ve-re : (x : Isomorphism f) → (obv ∘ inv) x ≡ x
|
||||
ve-re = Equiv≃.inverse-to-from-iso A B sA sB
|
||||
ve-re = inverse-to-from-iso A B sA sB
|
||||
iso : isEquiv A B f ≅ Isomorphism f
|
||||
iso = obv , inv ,
|
||||
record
|
||||
{ verso-recto = funExt re-ve
|
||||
; recto-verso = funExt ve-re
|
||||
}
|
||||
in fromIsomorphism iso
|
||||
in fromIsomorphism _ _ iso
|
||||
|
|
|
@ -24,7 +24,7 @@ open import Cubical.NType.Properties
|
|||
using
|
||||
( lemPropF ; lemSig ; lemSigP ; isSetIsProp
|
||||
; propPi ; propPiImpl ; propHasLevel ; setPi ; propSet
|
||||
; propSig)
|
||||
; propSig ; equivPreservesNType)
|
||||
public
|
||||
|
||||
propIsContr : {ℓ : Level} → {A : Set ℓ} → isProp (isContr A)
|
||||
|
|
Loading…
Reference in a new issue