let C, B be Category; :: thesis: for S being Contravariant_Functor of C,B
for c being Object of C holds (S *' ) . (id c) = id (((Obj S) . c) opp )
let S be Contravariant_Functor of C,B; :: thesis: for c being Object of C holds (S *' ) . (id c) = id (((Obj S) . c) opp )
let c be Object of C; :: thesis: (S *' ) . (id c) = id (((Obj S) . c) opp )
thus (S *' ) . (id c) = (S . (id c)) opp by Def9
.= (id ((Obj S) . c)) opp by Th32
.= id (((Obj S) . c) opp ) ; :: thesis: verum