
theorem
  for L1,L2 being non empty \/-SemiLattStr st the \/-SemiLattStr of L1 =
the \/-SemiLattStr of L2 for a1,b1 being Element of L1, a2,b2 being Element of
  L2 st a1 = a2 & b1 = b2 holds a1 "\/" b1 = a2 "\/" b2;
