proposition: Lemma arg_mul_arg : forall m M, m in (list2multiset (appArgs M)) -> isArg m M.
proof: Proof. intros m M m_in_M. destruct (member_multiset_list (appArgs M) m_in_M) as [m' m'_in_M m_m']. unfold eqA in m_m'; unfold TermsEqset.eqA in m_m'; rewrite m_m'; trivial. Qed.
imports: CoLoR(RelExtras ListExtras Horpo Computability PairLex HorpoComp LogicUtil)