proposition: Lemma abs_subst_abs M (Mabs: isAbs M) G (CS: correct_subst M G) : isAbs (subst CS).
proof: Proof. term_inv M. apply abs_isAbs with A (presubst_aux Pt 1 (None::G)). rewrite subst_term; auto. Qed.
imports: CoLoR(RelExtras ListPermutation TermsConv ListUtil ListExtras LogicUtil) Coq(Arith Lia)