fact: Definition comma_category_projection_functor_object_of (ST : object ((A -> C)^op * (B -> C))) : Cat / !((A * B; PAB) : Cat).
imports: Category.Core Functor.Core Category.Prod Functor.Prod.Core Category.Dual Functor.Dual Functor.Composition.Core InitialTerminalCategory.Core InitialTerminalCategory.Functors NatCategory FunctorCategory.Core Cat.Core Functor.Paths Comma.InducedFunctors Comma.Projection Types.Forall PathGroupoids HoTT.Tactics