
theorem Th16: :: 4.19
  for L being join-commutative join-associative Huntington non
empty ComplLLattStr, a, b, c being Element of L
 holds a *' (b *' c) = a *' b *' c
proof
  let L be join-commutative join-associative Huntington non empty
  ComplLLattStr, a, b, c be Element of L;
  thus a *' b *' c = (a` + b` + c`)` by Th3
    .= (a` + (b` + c`))` by LATTICES:def 5
    .= a *' (b *' c) by Th3;
end;
