reserve p,q,r for FinSequence,
  x,y for object;

theorem
  (p^<*x*>)$^(<*y*>^q) = p^<*y*>^q
proof
  p^<*y*>^q = p^(<*y*>^q) by FINSEQ_1:32;
  hence thesis by Th2;
end;
