fact: Fixpoint Acc_iter {A:Type}(R:A->A->Prop)(P:A->Type) (f:forall x:A, (forall y:A, R y x -> P y)-> P x)(x:A) (hacc:Acc R x){struct hacc} : P x := f x (fun (y:A)(hy:R y x) => Acc_iter R P f y (Acc_inv R x hacc y hy)).
imports: ZArith List Arith Lia Zwf Inverse_Image Extraction