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

theorem Th33:
  Finf(A,1) = A^f
proof
  (Finf A).0=A & for B being Subset of T st B=(Finf A).0 holds (Finf A).(0
  +1)= B^f by Def6;
  hence thesis;
end;
