
theorem
  for L being reflexive antisymmetric with_suprema RelStr for a being
  Element of L holds a "\/" a = a
proof
  let L be reflexive antisymmetric with_suprema RelStr, a be Element of L;
  a <= a;
  then a <= a "\/" a & a "\/" a <= a by YELLOW_0:22;
  hence thesis by YELLOW_0:def 3;
end;
