
theorem
  for X, Y being non empty TopSpace, f being Function of X, Y st corestr
  f is continuous holds f is continuous
proof
  let X, Y be non empty TopSpace, f be Function of X, Y such that
A1: corestr f is continuous;
  corestr f = f by WAYBEL18:def 7;
  hence thesis by A1,PRE_TOPC:26;
end;
