 reserve L for non empty LattStr;
 reserve v100,v102,v2,v1,v0,v3,v101 for Element of L;
 reserve L for WA_Lattice;
 reserve x,y,z,u for Element of L;

theorem Lemacik2:
  z [= x & z [= y implies z [= x "/\" y
  proof
    assume z [= x & z [= y; then
    z "\/" x = x & z "\/" y = y by LATTICES:def 3;
    hence thesis by defW3;
  end;
