Definition FLIP mu :=
  match mu with
    Build_SM_Injection locBSrc locBTgt pSrc pTgt local extBSrc extBTgt fSrc fTgt extern =>
    Build_SM_Injection extBSrc extBTgt fSrc fTgt extern locBSrc locBTgt pSrc pTgt local
  end.

Lemma SAWP_wd: forall mu (WD: SM_wd mu), SM_wd (FLIP mu).