fact: Definition Under_mor (X Y : Under_ob) : UU := ∑ f : C⟦Under_ob_cod X, Under_ob_cod Y⟧, Under_ob_mor X · f = Under_ob_mor Y.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors