reserve n,m,k for Nat,
  x,X for set,
  A for Subset of X,
  A1,A2 for SetSequence of X;

theorem Th60:
  lim_inf (A1 (/\) A2) = lim_inf A1 /\ lim_inf A2
proof
  (A1 (/\) A2).n = A1.n /\ A2.n by Def1;
  hence thesis by KURATO_0:10;
end;
