 reserve W for WA-Lattice;
 reserve a,b,c for Element of W;
 reserve W for pcs-Compatible pcs-tol-reflexive pcs-tol-symmetric WAP-Lattice;
 reserve a,b for Element of W;

theorem
  for a, b being Element of W holds
    a (--) b & b (--) b implies (a "/\" b) (--) (b "/\" b)
      by CompDef;
