
theorem
  for H being non empty RelStr st H is Heyting for a being Element of H
  holds Top H = a => a
proof
  let H be non empty RelStr;
  assume
A1: H is Heyting;
  let a be Element of H;
  a >= a "/\" Top H by A1,YELLOW_0:23;
  then
A2: Top H <= a => a by A1,Th67;
  Top H >= a => a by A1,YELLOW_0:45;
  hence thesis by A1,A2,ORDERS_2:2;
end;
