fact: Definition split_idempotent_is_split {c : C} (e : split_idempotent c) : split_idempotent_morphism e = split_idempotent_retraction e · retraction_section (split_idempotent_retraction e) := pr222 e.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors