reserve V for non empty set,
  A,B,A9,B9 for Element of V;

theorem
  Funcs(A,B) c= Funcs(V)
proof
  let x be object;
  assume
A1: x in Funcs(A,B);
  then
A2: x is Function of A,B by FUNCT_2:66;
  B={} implies A={} by A1;
  hence thesis by A2,Th1;
end;
