
theorem Th2:
  for L being add-associative right_zeroed right_complementable
  Abelian non empty addLoopStr, b, c being Element of L holds c = b - (b - c)
proof
  let L be add-associative right_zeroed right_complementable Abelian non
  empty addLoopStr, b, c be Element of L;
  set a = b - c;
  a+c-a = c-a+a by RLVECT_1:28
    .= c by Th1;
  hence thesis by Th1;
end;
