Use a single version of \simeq

This commit is contained in:
Frederik Hanghøj Iversen 2018-04-06 18:27:24 +02:00
parent 36d92c7ceb
commit 69689e7b2a
8 changed files with 91 additions and 149 deletions

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@ -33,9 +33,6 @@ module _ (a b : Level) where
isIdentity : IsIdentity λ { {A} identity {A} }
isIdentity = (Σ≡ refl refl) , Σ≡ refl refl
open import Cubical.NType.Properties
open import Cubical.Sigma
isPreCategory : IsPreCategory RawFam
IsPreCategory.isAssociative isPreCategory
{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 {c c' d d' : Level} ( : Category c c') (𝔻 : C
F[ F G~ ] ≡⟨ prop1
idFunctor
open import Cubical.Univalence
p0 : F G
p0 = begin
F ≡⟨ sym Functors.rightIdentity

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@ -2,21 +2,15 @@
{-# OPTIONS --allow-unsolved-metas --cubical --caching #-}
module Cat.Categories.Sets where
open import Cat.Prelude as P hiding (_≃_)
open import Cat.Prelude as P
open import Function using (_∘_ ; _∘_)
open import Cubical.Univalence using (univalence ; con ; _≃_ ; idtoeqv ; ua)
open import Cat.Category
open import Cat.Category.Functor
open import Cat.Category.Product
open import Cat.Wishlist
open import Cat.Equivalence as Eqv using (AreInverses ; module Equiv ; module NoEta)
open NoEta
module Equivalence = Equivalence
open import Cat.Equivalence renaming (_≅_ to _≈_)
_⊙_ : {a b c : Level} {A : Set a} {B : Set b} {C : Set c} (A B) (B C) A C
eqA eqB = Equivalence.compose eqA eqB
@ -52,7 +46,7 @@ module _ ( : Level) where
open IsPreCategory isPreCat hiding (_∘_)
isIso = Eqv.Isomorphism
isIso = TypeIsomorphism
module _ {hA hB : hSet } where
open Σ hA renaming (fst to A ; snd to sA)
open Σ hB renaming (fst to B ; snd to sB)
@ -95,7 +89,7 @@ module _ ( : Level) where
module _ {a b : Level} {A : Set a} {P : A Set b} where
lem2 : ((x : A) isProp (P x)) (p q : Σ A P)
(p q) (fst p fst q)
lem2 pA p q = fromIsomorphism iso
lem2 pA p q = fromIsomorphism _ _ iso
where
f : {p q} p q fst p fst q
f e i = fst (e i)
@ -111,7 +105,7 @@ module _ ( : Level) where
{ verso-recto = funExt ve-re
; recto-verso = funExt re-ve
}
iso : (p q) Eqv.≅ (fst p fst q)
iso : (p q) (fst p fst q)
iso = f , g , inv
lem3 : {c} {Q : A Set (c b)}
@ -119,12 +113,12 @@ module _ ( : Level) where
lem3 {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 : Eqv.Isomorphism _
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
k : TypeIsomorphism _
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
@ -133,16 +127,16 @@ module _ ( : Level) 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 : Eqv.Isomorphism _
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
k : TypeIsomorphism _
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
@ -150,11 +144,11 @@ module _ ( : Level) 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 : Eqv.Isomorphism _
k = Equiv≃.toIso _ _ (_≃_.isEqv (eA a))
k : TypeIsomorphism _
k = toIso _ _ (snd (eA a))
open Σ k renaming (fst to g' ; snd to inv)
module A = AreInverses inv
inv : AreInverses f g
@ -162,10 +156,10 @@ module _ ( : Level) where
{ verso-recto = funExt ve-re
; recto-verso = funExt re-ve
}
iso : Σ A P Eqv.≅ Σ A Q
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 _ {a b : Level} {A : Set a} {B : Set b} where
lem4 : isSet A isSet B (f : A B)
@ -173,20 +167,20 @@ module _ ( : Level) where
lem4 sA sB f =
let
obv : isEquiv A B f isIso f
obv = Equiv≃.toIso A B
obv = toIso A B
inv : isIso 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 : isIso f) (obv inv) x x
ve-re = Equiv≃.inverse-to-from-iso A B sA sB
iso : isEquiv A B f Eqv.≅ isIso f
ve-re = inverse-to-from-iso A B sA sB
iso : isEquiv A B f isIso f
iso = obv , inv ,
record
{ verso-recto = funExt re-ve
; recto-verso = funExt ve-re
}
in fromIsomorphism iso
in fromIsomorphism _ _ iso
module _ {hA hB : Object} where
open Σ hA renaming (fst to A ; snd to sA)
@ -198,33 +192,15 @@ module _ ( : Level) where
-- univalence
step1 : Σ (A B) (isEquiv A B) (A B)
step1 = hh h
where
h : (A B) (A B)
h = sym≃ (univalence {A = A} {B})
obv : Σ (A B) (isEquiv A B) A B
obv = Eqv.deEta
inv : A B Σ (A B) (isEquiv A B)
inv = Eqv.doEta
re-ve : (x : _) (inv obv) x x
re-ve x = refl
-- Because _≃_ does not have eta equality!
ve-re : (x : _) (obv inv) x x
ve-re (con eqv isEqv) i = con eqv isEqv
areInv : AreInverses obv inv
areInv = record { verso-recto = funExt re-ve ; recto-verso = funExt ve-re }
eqv : Σ (A B) (isEquiv A B) Eqv.≅ (A B)
eqv = obv , inv , areInv
hh : Σ (A B) (isEquiv A B) (A B)
hh = fromIsomorphism eqv
step1 = sym≃ univalence
-- lem2 with propIsSet
step2 : (A B) (hA hB)
step2 = sym≃ (lem2 (λ A isSetIsProp) hA hB)
-- Go from an isomorphism on sets to an isomorphism on homotopic sets
trivial? : (hA hB) (A Eqv.≅ B)
trivial? = sym≃ (fromIsomorphism res)
trivial? : (hA hB) (A B)
trivial? = sym≃ (fromIsomorphism _ _ res)
where
fwd : Σ (A B) isIso hA hB
fwd (f , g , inv) = f , g , inv.toPair
@ -232,7 +208,7 @@ module _ ( : Level) where
module inv = AreInverses inv
bwd : hA hB Σ (A B) isIso
bwd (f , g , x , y) = f , g , record { verso-recto = x ; recto-verso = y }
res : Σ (A B) isIso Eqv.≅ (hA hB)
res : Σ (A B) isIso (hA hB)
res = fwd , bwd , record { verso-recto = refl ; recto-verso = refl }
conclusion : (hA hB) (hA hB)
@ -274,7 +250,6 @@ module _ { : Level} where
private
𝓢 = 𝓢𝓮𝓽
open Category 𝓢
open import Cubical.Sigma
module _ (hA hB : Object) where
open Σ hA renaming (fst to A ; snd to sA)

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@ -29,6 +29,7 @@
module Cat.Category where
open import Cat.Prelude
open import Cat.Equivalence as Equivalence renaming (_≅_ to _≈_ ; Isomorphism to TypeIsomorphism) hiding (preorder≅)
import Function
@ -122,8 +123,6 @@ record RawCategory (a b : Level) : Set (lsuc (a ⊔ b)) where
import Cat.Equivalence as E
open E public using () renaming (Isomorphism to TypeIsomorphism)
open E using (module Equiv)
open Equiv≃ using (fromIso)
univalenceFromIsomorphism : {A B : Object}
TypeIsomorphism (idToIso A B) isEquiv (A B) (A B) (idToIso A B)
@ -299,10 +298,8 @@ module _ {a b : Level} ( : RawCategory a b) where
univalent≃ = _ , univalent
module _ {A B : Object} where
open import Cat.Equivalence using (module Equiv)
iso-to-id : (A B) (A B)
iso-to-id = fst (Equiv≃.toIso _ _ univalent)
iso-to-id = fst (toIso _ _ univalent)
-- | All projections are propositions.
module Propositionality where
@ -321,7 +318,6 @@ module _ {a b : Level} ( : RawCategory a b) where
open Σ Yt renaming (fst to Y ; snd to Yit)
open Σ (Xit {Y}) renaming (fst to Y→X) using ()
open Σ (Yit {X}) renaming (fst to X→Y) using ()
open import Cat.Equivalence hiding (_≅_)
-- Need to show `left` and `right`, what we know is that the arrows are
-- unique. Well, I know that if I compose these two arrows they must give
-- the identity, since also the identity is the unique such arrow (by X
@ -336,10 +332,10 @@ module _ {a b : Level} ( : RawCategory a b) where
right = Yprop _ _
iso : X Y
iso = X→Y , Y→X , left , right
fromIso : X Y X Y
fromIso = fst (Equiv≃.toIso (X Y) (X Y) univalent)
fromIso' : X Y X Y
fromIso' = fst (toIso (X Y) (X Y) univalent)
p0 : X Y
p0 = fromIso iso
p0 = fromIso' iso
p1 : (λ i IsTerminal (p0 i)) [ Xit Yit ]
p1 = lemPropF propIsTerminal p0
res : Xt Yt
@ -354,7 +350,6 @@ module _ {a b : Level} ( : RawCategory a b) where
open Σ Yi renaming (fst to Y ; snd to Yii)
open Σ (Xii {Y}) renaming (fst to Y→X) using ()
open Σ (Yii {X}) renaming (fst to X→Y) using ()
open import Cat.Equivalence hiding (_≅_)
-- Need to show `left` and `right`, what we know is that the arrows are
-- unique. Well, I know that if I compose these two arrows they must give
-- the identity, since also the identity is the unique such arrow (by X
@ -369,10 +364,10 @@ module _ {a b : Level} ( : RawCategory a b) where
right = Xprop _ _
iso : X Y
iso = Y→X , X→Y , right , left
fromIso : X Y X Y
fromIso = fst (Equiv≃.toIso (X Y) (X Y) univalent)
fromIso' : X Y X Y
fromIso' = fst (toIso (X Y) (X Y) univalent)
p0 : X Y
p0 = fromIso iso
p0 = fromIso' iso
p1 : (λ i IsInitial (p0 i)) [ Xii Yii ]
p1 = lemPropF propIsInitial p0
res : Xi Yi
@ -436,9 +431,12 @@ module _ {a b : Level} ( : RawCategory a b) where
propIsCategory : isProp (IsCategory )
propIsCategory = done
-- | Univalent categories
--
-- Just bundles up the data with witnesses inhabiting the propositions.
-- Question: Should I remove the type `Category`?
record Category (a b : Level) : Set (lsuc (a b)) where
field
raw : RawCategory a b
@ -459,10 +457,8 @@ module _ {a b : Level} { 𝔻 : Category a b} where
isCategoryEq = lemPropF propIsCategory rawEq
Category≡ : 𝔻
Category≡ i = record
{ raw = rawEq i
; isCategory = isCategoryEq i
}
Category.raw (Category≡ i) = rawEq i
Category.isCategory (Category≡ i) = isCategoryEq i
-- | Syntax for arrows- and composition in a given category.
module _ {a b : Level} ( : Category a b) where
@ -501,9 +497,8 @@ module Opposite {a b : Level} where
open IsPreCategory isPreCategory
module _ {A B : .Object} where
open import Cat.Equivalence as Equivalence hiding (_≅_)
k : Equivalence.Isomorphism (.idToIso A B)
k = Equiv≃.toIso _ _ .univalent
k = toIso _ _ .univalent
open Σ k renaming (fst to f ; snd to inv)
open AreInverses inv
@ -568,7 +563,7 @@ module Opposite {a b : Level} where
h = ff , invv
univalent : isEquiv (A B) (A B)
(Univalence.idToIso (swap .isIdentity) A B)
univalent = Equiv≃.fromIso _ _ h
univalent = fromIso _ _ h
isCategory : IsCategory opRaw
IsCategory.isPreCategory isCategory = isPreCategory

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@ -5,7 +5,6 @@ open import Cat.Prelude
open import Function
open import Cubical
open import Cubical.NType.Properties using (lemPropF)
open import Cat.Category

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@ -1,8 +1,8 @@
{-# OPTIONS --allow-unsolved-metas --cubical #-}
module Cat.Category.Product where
open import Cubical.NType.Properties
open import Cat.Prelude as P hiding (_×_ ; fst ; snd)
open import Cat.Equivalence hiding (_≅_)
-- module P = Cat.Prelude
open import Cat.Category
@ -285,10 +285,8 @@ module Try0 {a b : Level} { : Category a b}
open Category cat
open import Cat.Equivalence
lemma : Terminal Product A B
lemma = Equiv≃.fromIsomorphism Terminal (Product A B) (f , g , inv)
lemma = fromIsomorphism Terminal (Product A B) (f , g , inv)
where
f : Terminal Product A B
f ((X , x0 , x1) , uniq) = p

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@ -3,11 +3,26 @@ module Cat.Equivalence where
open import Cubical.Primitives
open import Cubical.FromStdLib renaming (-max to _⊔_)
-- FIXME: Don't hide ≃
open import Cubical.PathPrelude hiding (inverse ; _≃_)
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 _ {a b : Level} {A : Set a} {B : Set b} 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 _ { : Level} {A B : Set } where
open Cubical.PathPrelude
ua : A B A B
ua (f , isEqv) = U.ua (U.con f isEqv)
module _ {a b : Level} where
private
@ -242,8 +257,7 @@ module _ {a b : Level} (A : Set a) (B : Set b) where
where
import Cubical.NType.Properties as P
module Equiv where
open Equiv ≃isEquiv public
open Equiv ≃isEquiv public
module _ {a b : Level} {A : Set a} {B : Set b} where
open Cubical.PathPrelude using (_≃_)
@ -273,20 +287,19 @@ module _ {a b : Level} {A : Set a} {B : Set b} 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 : {c : Level} {C : Set c} (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 _ {a b : Level} {A : Set a} {B : Set b} where
}
symmetry : B A
symmetry = B≃A.fromIsomorphism symmetryIso
where
module B≃A = Equiv≃ B A
symmetry = fromIsomorphism _ _ symmetryIso
preorder≅ : ( : Level) Preorder _ _ _
preorder≅ = record
@ -323,54 +334,24 @@ preorder≅ = record
; trans = composeIso
}
}
module _ {a b : Level} {A : Set a} {B : Set b} 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 {a b : Level} {A : Set a} {B : Set b} 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 : {c : Level} {C : Set c} (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 _ { : Level} {A B : Set } 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 _ {a b : Level} {A : Set a} {P : A Set b} 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 _ {a b : Level} {A : Set a} {P : A → Set b} 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 _ {a b : Level} {A : Set a} {P : A → Set b} 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 _ {a b : Level} {A : Set a} {P : A → Set b} 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 _ {a b : Level} {A : Set a} {P : A → Set b} 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 _ {a b : Level} {A : Set a} {B : Set b} 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 _ {a b : Level} {A : Set a} {B : Set b} 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

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@ -24,7 +24,7 @@ open import Cubical.NType.Properties
using
( lemPropF ; lemSig ; lemSigP ; isSetIsProp
; propPi ; propPiImpl ; propHasLevel ; setPi ; propSet
; propSig)
; propSig ; equivPreservesNType)
public
propIsContr : { : Level} {A : Set } isProp (isContr A)