
theorem
  for H being non empty RelStr st H is Heyting for a being Element of H
  holds Top H = a => Top H
proof
  let H be non empty RelStr;
  assume
A1: H is Heyting;
  let a be Element of H;
  a <= Top H by A1,YELLOW_0:45;
  hence thesis by A1,Th69;
end;
