reserve T for non empty RelStr,
  A,B for Subset of T,
  x,x2,y,z for Element of T;

theorem
  for n being Nat holds Fint(A,n) /\ Fint(B,n) = Fcl((A /\ B) `,n)`
proof
  let n be Nat;
  Fint(A,n) /\ Fint(B,n) = Fint(A /\ B,n) by Th22
    .= Fcl((A /\ B)`,n)` by Th28;
  hence thesis;
end;
