
theorem Th2:
  for I being non degenerated non empty multLoopStr_0 for u being
  Element of Q.I holds u`2 <> 0.I
proof
  let I be non degenerated non empty multLoopStr_0;
  let u be Element of Q.I;
  ex a,b being Element of I st u = [a,b] & b <> 0.I by Def1;
  hence thesis;
end;
