fact: Fixpoint erase (E : list (asn A B)) : list B := match E with | nil => nil | (AltAsn _ b) :: E => b :: erase E | (VarAsn _ x a) :: E => erase E end.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics