proposition: Lemma swapVarSwitch : forall (sw : Swapping vc) (v : vType vc), swapVar sw v = swapVar (ALSwitch sw) v.
proof: Proof. induction sw as [|(l,r) sw Hind]; auto;[]. intros. simpl. ddeq; subst; cpx. subst; intuition. Qed.
imports: Swap AssociationList Eqdep_dec