proposition: Lemma abstr_correct : forall (t s : Term) (v : nat), NoLambdas t -> abstr v t @ s =w csubst t v s.
proof: Proof. induction t; scrush. Qed.
imports: Hammer(Tactics) Arith ZArith List Lia Hammer(Hints) Reals Lra Hammer(Reflect) Nat Psatz