 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  :: Theorem 3.8. 1) <=> 5)
  x "\/" y = y "\/" x iff x [= y "\/" x by LemX3,Th3851;
