fact: Definition eq_in_set_fiber {C : setcategory} {F : C ⟶ cat_of_setcategory} {x₁ x₂ : C} {f g : F x₁ --> F x₂} (p : f = g) (y : pr1 (F x₁)) : pr11 f y = pr11 g y.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Setcategories UniMath.CategoryTheory.Categories.CategoryOfSetCategories