
theorem Th32:
  for L being non empty RelStr, f being Function of L,L holds (
  inclusion f)*(corestr f) = f
proof
  let L be non empty RelStr, f be Function of L,L;
  thus (inclusion f)*(corestr f) = (id the carrier of Image f)*f by Th30
    .= (id rng f)*f by YELLOW_0:def 15
    .= f by RELAT_1:54;
end;
