
theorem Th15: :: 4.17
  for L being join-commutative join-associative Huntington non
  empty ComplLLattStr, a being Element of L holds a *' a` = Bot L
proof
  let L be join-commutative join-associative Huntington non empty
  ComplLLattStr, a be Element of L;
  thus a *' a` = (Top L)` by Def8
    .= Bot L by Th9;
end;
