
theorem
  for L being non empty RelStr, X being set st ex_inf_of X,L or
ex_inf_of X /\ the carrier of L, L holds "/\"(X,L) = "/\"(X /\ the carrier of L
  , L)
proof
  let L be non empty RelStr, X be set;
  set Y = X /\ the carrier of L;
  assume
A1: ex_inf_of X,L or ex_inf_of Y,L;
  for x being Element of L holds x is_<=_than X iff x is_<=_than Y by Th5;
  hence thesis by A1,Th49;
end;
