proposition: Lemma ngs_S: forall i, 0 <= i -> 2 * nth_gen_size (Z.to_nat i) = nth_gen_size (Z.to_nat (i + 1)).
proof: Proof. intros. unfold nth_gen_size. rewrite !Z2Nat.id by lia. rewrite Z.mul_comm, <- Z.mul_assoc, (Z.mul_comm (two_p i)), <- two_p_S by assumption. reflexivity. Qed.
imports: Coq.ZArith.ZArith Coq.Program.Basics Coq.micromega.Lia compcert.lib.Integers compcert.common.Values VST.veric.base VST.veric.Clight_lemmas VST.veric.val_lemmas VST.veric.shares VST.msl.seplog VST.msl.shares VST.zlist.sublist VST.floyd.coqlib3 VST.floyd.functional_base VST.floyd.data_at_rec_lemmas VST.zlist.list_solver CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen