proposition: Lemma is_sol_eqn_sub : forall s s' e, is_sol_eqn s e -> is_sol_eqn (sub_comp s' s) e.
proof: Proof. intros s s' e. destruct e. unfold is_sol_eqn. simpl. intro. rewrite <- !sub_sub. f_equal. hyp. Qed.
imports: Coq(Relations Wellfounded) CoLoR(ASubstitution ATerm EqUtil ListUtil LogicUtil VecUtil AVariables BoolUtil NatUtil SN AVariables Lexico)