diff --git a/Cubical/Foundations/Equiv.agda b/Cubical/Foundations/Equiv.agda index c3a6e346db..2c12278bfa 100644 --- a/Cubical/Foundations/Equiv.agda +++ b/Cubical/Foundations/Equiv.agda @@ -316,3 +316,16 @@ isEquiv-isEquiv'-Iso f .leftInv p i .equiv-proof = p .equiv-proof isEquiv≃isEquiv' : (f : A → B) → isEquiv f ≃ isEquiv' f isEquiv≃isEquiv' f = isoToEquiv (isEquiv-isEquiv'-Iso f) + +-- funExt is an equivalence + +funExt≃ : {B : A → I → Type ℓ'} {f : (x : A) → B x i0} {g : (x : A) → B x i1} → + ((x : A) → PathP (B x) (f x) (g x)) ≃ PathP (λ i → (x : A) → B x i) f g +funExt≃ {A = A}{B = B} {f = f} {g = g} = isoToEquiv e + where + open Iso + e : Iso ((x : A) → PathP (B x) (f x) (g x)) (PathP (λ i → (x : A) → B x i) f g) + fun e p = funExt p + inv e p = funExt⁻ p + rightInv e p = refl + leftInv e p = refl