fact: Structure Pullback : Type := {Fibred_prod : C; Fibred_p : Fibred_prod --> a; Fibred_q : Fibred_prod --> c; Prf_pb_law1 : Pullback_law1 Fibred_p Fibred_q; Pb_diese : forall (r : C) (t1 : r --> a) (t2 : r --> c), Pullback_eq1 t1 t2 -> (r --> Fibred_prod); Prf_pb_law2 : Pullback_law2 Fibred_p Pb_diese; Prf_pb_law3 : Pullback_law3 Fibred_q Pb_diese; Prf_pb_law4 : Pullback_law4 Fibred_p Fibred_q Pb_diese}.
imports: CatProperty