intros;induction ll;simpl.
rewrite orb_true_r;reflexivity.
unfold CNFtoPropF in IHll at 1;rewrite IHll.
rewrite CNF_or_clause_valid.
rewrite orb_andb_distrib_r.
reflexivity.
Qed.

Lemma CNF_or_valid : forall v ll1 ll2, TrueQ v (CNFtoPropF (Disjunct ll1 ll2)) =
TrueQ v (CNFtoPropF ll1) || TrueQ v (CNFtoPropF ll2).