fact: Definition def_prod_algebra_mapin (f : ∀ (i:I) s, C s → A i s) : ∀ (s : Sort σ) , C s → ProdAlgebra I A s := λ (s : Sort σ) (x : C s) (i : I), f i s x.
imports: HoTT.Types.Bool HoTT.Types.Forall HoTT.Classes.theory.ua_homomorphism