theorem Th79:
  for T being Functor of C,D for c,c9 being Object of C st Hom(c,
  c9) <> {} holds Hom(T.c,T.c9) <> {}
proof
  let T be Functor of C,D;
  let c,c9 be Object of C;
  set f = the Element of Hom(c,c9);
  assume Hom(c,c9) <> {};
  then f in Hom(c,c9);
  hence thesis by Th76;
end;
