proposition: Lemma tc2ai3 l ll : tc2i3 l ll = false -> valid3 l -> tc2i3 l (tc2a3 l ll) = true.
proof: Proof. destruct l as ((l1,l2),p1); simpl. intros H1 (H2, (H3, H4)). apply tc2ai; auto. Qed.
imports: PrimInt63 Cyclic63 List BasicRubik Max