reserve A,B,C for Category,
  F,F1 for Functor of A,B;
reserve o,m for set;
reserve t for natural_transformation of F,F1;

theorem Th5:
  o is Object of Functors(A,B) iff o is Functor of A,B
proof
  the carrier of Functors(A,B) = Funct(A,B) by NATTRA_1:def 17;
  hence thesis by CAT_2:def 2;
end;
