
theorem Th68:
  for H being non empty RelStr st H is Heyting holds H is upper-bounded
proof
  let H be non empty RelStr;
  assume
A1: H is Heyting;
  set a = the Element of H;
  take a => a;
  let y be Element of H;
  assume y in the carrier of H;
  a >= a "/\" y by A1,YELLOW_0:23;
  hence thesis by A1,Th67;
end;
