 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
  ex z st z [= x & z [= y &
    for u st u [= x & u [= y holds u [= z
  proof
    take z = x "/\" y;
    thus thesis by Lemacik2,Lemacik3;
  end;
