proposition: Lemma is_z_iso_comp_of_is_z_isos {C : precategory} {a b c : ob C} (f : a --> b) (g : b --> c) (H1 : is_z_isomorphism f) (H2 : is_z_isomorphism g) : is_z_isomorphism (f · g).
proof: Proof. set (i1 := make_z_iso f _ H1). set (i2 := make_z_iso g _ H2). exact (pr2 (z_iso_comp i1 i2)). Defined.
imports: UniMath.Foundations.PartA UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories