epeat split; eauto 1.
      * apply (@erased_a_CPi (L \u D)); eauto.
        intros c0 Hi5.
        destruct (IHDefEq c0) as [Ac' h2']; auto; subst.
        apply Good_NoAssn; auto.
        apply h2'.
      * apply (@erased_a_CPi (L \u D)); eauto.
        intros c0 Hi5.
        destruct (IHDefEq c0) as [Ac' h2']; auto; subst.
        apply Good_NoAssn; auto.
        apply h2'.
      * (* Ltac context_independence c := *)
(*        eapply multipar_context_independent; eauto.

+ destruct H1 as [ a' [K W]]. rewrite K in H. assert (h0 : x `notin` fv_tm_tm_