theorem
  for f1 be PartFunc of C,REAL holds f1 is total & f2 is total implies
  (f1(#)f2)/.c = f1.c * (f2/.c)
proof
  let f1 be PartFunc of C,REAL;
  assume f1 is total & f2 is total;
  then dom (f1(#)f2) = C by PARTFUN1:def 2;
  hence thesis by Def3;
end;
