
theorem Th15:
  for V being RealNormSpace,
      x be Point of DualSp V holds
   0.V .|. x = 0
proof
  let V be RealNormSpace,
      x be Point of DualSp V;
  thus 0.V .|. x
  = (0* (0.V)) .|. x
  .= 0* 0.V .|. x by Th6
  .= 0;
end;
