reserve r,s,t,u for Real;

theorem Th9:
  for X being add-associative right_zeroed right_complementable
non empty addLoopStr, M being Subset of X, x being Point of X st x in M holds
  0.X in -x+M
proof
  let X be add-associative right_zeroed right_complementable non empty
  addLoopStr, M be Subset of X, x be Point of X;
  assume x in M;
  then -x+x in -x+M by Lm1;
  hence thesis by RLVECT_1:5;
end;
