theorem Th14:
  for f be FinSequence st len f >= 2 holds Center f > 1
proof
  let f be FinSequence;
  assume len f >= 2;
  then len f div 2 >= 1 by NAT_2:13;
  then len f div 2 + 1 > 1 by NAT_1:13;
  hence thesis by JORDAN1A:def 1;
end;
