theorem
  for f being FinSequence holds f^'<*x*> = f
proof
  let f be FinSequence;
  len <*x*> = 1 by FINSEQ_1:39;
  then (2, len <*x*>)-cut <*x*> = {} by Def1;
  hence thesis by FINSEQ_1:34;
end;
