
theorem Th15:
  for L being non empty ZeroStr, p being Polynomial of L st len p
  > 0 holds p.(len p -'1) <> 0.L
proof
  let L be non empty ZeroStr, p be Polynomial of L;
  assume len p > 0;
  then ex k being Nat st len p = k+1 by NAT_1:6;
  then len p = (len p -'1)+1 by NAT_D:34;
  hence thesis by ALGSEQ_1:10;
end;
