Lean4
/-- Isomorphic monads give equivalent categories of algebras. Furthermore, they are equivalent as
categories over `C`, that is, we have `algebraEquivOfIsoMonads h ⋙ forget = forget`.
-/
@[simps]
def algebraEquivOfIsoMonads {T₁ T₂ : Monad C} (h : T₁ ≅ T₂) : Algebra T₁ ≌ Algebra T₂
where
functor := algebraFunctorOfMonadHom h.inv
inverse := algebraFunctorOfMonadHom h.hom
unitIso := algebraFunctorOfMonadHomId.symm ≪≫ algebraFunctorOfMonadHomEq (by simp) ≪≫ algebraFunctorOfMonadHomComp _ _
counitIso :=
(algebraFunctorOfMonadHomComp _ _).symm ≪≫ algebraFunctorOfMonadHomEq (by simp) ≪≫ algebraFunctorOfMonadHomId