reserve n for Nat;

theorem Th9:
  for x be Point of REAL-NS n, y be Element of REAL n st x=y holds
  for i be Nat st i in Seg n holds |.y.i.| <= ||.x.||
proof
  let x be Point of REAL-NS n, y be Element of REAL n;
  assume x=y;
  then ||.x.|| = |.y.| by Th1;
  hence thesis by Th8;
end;
