diff --git a/library/hott/equiv_precomp.lean b/library/hott/equiv_precomp.lean index ed38539bf..2b25c2c0f 100644 --- a/library/hott/equiv_precomp.lean +++ b/library/hott/equiv_precomp.lean @@ -15,14 +15,14 @@ namespace is_equiv definition postcomp {A B : Type} (f : A → B) (C : Type) (l : C → A) : C → B := f ∘ l --Precomposing with an equivalence is an equivalence - definition precompose [instance] {A B : Type} (f : A → B) [F : funext] [Hf : is_equiv f] (C : Type) + definition precomp_closed [instance] {A B : Type} (f : A → B) [F : funext] [Hf : is_equiv f] (C : Type) : is_equiv (precomp f C) := adjointify (precomp f C) (λh, h ∘ f⁻¹) (λh, path_forall _ _ (λx, ap h (sect f x))) (λg, path_forall _ _ (λy, ap g (retr f y))) --Postcomposing with an equivalence is an equivalence - definition postcompose [instance] {A B : Type} (f : A → B) [F : funext] [Hf : is_equiv f] (C : Type) + definition postcomp_closed [instance] {A B : Type} (f : A → B) [F : funext] [Hf : is_equiv f] (C : Type) : is_equiv (postcomp f C) := adjointify (postcomp f C) (λl, f⁻¹ ∘ l) (λh, path_forall _ _ (λx, retr f (h x))) @@ -42,7 +42,7 @@ namespace is_equiv ... ≈ k ∘ (invC h) : !sect, eq1⁻¹ - definition isequiv_precompose {A B : Type} (f : A → B) (Aeq : is_equiv (precomp f A)) + definition from_isequiv_precomp {A B : Type} (f : A → B) (Aeq : is_equiv (precomp f A)) (Beq : is_equiv (precomp f B)) : (is_equiv f) := let invA := inv (precomp f A) in let invB := inv (precomp f B) in @@ -64,18 +64,18 @@ end is_equiv --Bundled versions of the previous theorems namespace equiv - definition precompose [F : funext] {A B C : Type} {eqf : A ≃ B} + definition precomp_closed [F : funext] {A B C : Type} {eqf : A ≃ B} : (B → C) ≃ (A → C) := let f := to_fun eqf in let Hf := to_is_equiv eqf in equiv.mk (is_equiv.precomp f C) - (@is_equiv.precompose A B f F Hf C) + (@is_equiv.precomp_closed A B f F Hf C) - definition postcompose [F : funext] {A B C : Type} {eqf : A ≃ B} + definition postcomp_closed [F : funext] {A B C : Type} {eqf : A ≃ B} : (C → A) ≃ (C → B) := let f := to_fun eqf in let Hf := to_is_equiv eqf in equiv.mk (is_equiv.postcomp f C) - (@is_equiv.postcompose A B f F Hf C) + (@is_equiv.postcomp_closed A B f F Hf C) end equiv