reserve x,y,X,X1,Y,Z for set;
reserve L for Lattice;
reserve F,H for Filter of L;
reserve p,q,r for Element of L;
reserve L1, L2 for Lattice;
reserve a1,b1 for Element of L1;
reserve a2 for Element of L2;
reserve f for Homomorphism of L1,L2;

theorem Th6: ::: GROUP_6:58
  for f being Function of L1,L2
  holds f is onto implies for a2 being Element of L2
  ex a1 being Element of L1 st a2 = f.a1
    by GROUP_6:58;
