reserve V for non empty RLSStruct;
reserve x,y,y1 for set;
reserve v for VECTOR of V;
reserve a,b for Real;

theorem Th5:
  for V being add-associative right_zeroed right_complementable
  non empty addLoopStr, v being Element of V holds v + -v = 0.V & -v + v = 0.V
proof
  let V be add-associative right_zeroed right_complementable non empty
  addLoopStr, v be Element of V;
  thus v + -v = 0.V by Def10;
  hence thesis by Lm1;
end;
