  \(O(OA\rightarrow A)\) is another deontic axiom that seems desirable. Although it is wrong to say that if \(A\) is obligatory then \(A\) is the case \((OA\rightarrow A)\), still, this conditional ought to be the case. So some deontic logicians believe that \(D\) needs to be supplemented with \(O(OA\rightarrow A)\) as well.