
theorem :: 4.22
  for L being join-commutative join-associative Huntington non empty
  ComplLLattStr, a being Element of L holds a + Top L = Top L
proof
  let L be join-commutative join-associative Huntington non empty
  ComplLLattStr, a be Element of L;
  thus a + Top L = a + (a + a`) by Def8
    .= a + a + a` by LATTICES:def 5
    .= a + a` by Def7
    .= Top L by Def8;
end;
