 reserve L for AD_Lattice;
 reserve x,y,z for Element of L;
 reserve L for GAD_Lattice;
 reserve x,y,z for Element of L;

theorem Lem36c:   :: Lemma 3.6. (3)
  x "/\" (y "/\" x) = y "/\" x
  proof
    for v2, v0 be Element of L holds
      v2 "/\" (v0 "/\" v2) = v0 "/\" v2
    proof
      let v2, v0 be Element of L;
      (v0 "/\" v2) "\/" v2 = v2 by LATTICES:def 8;
      hence thesis by DefA2;
    end;
    hence thesis;
  end;
