diff options
Diffstat (limited to 'theories/Numbers/Cyclic/Abstract/NZCyclic.v')
| -rw-r--r-- | theories/Numbers/Cyclic/Abstract/NZCyclic.v | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/theories/Numbers/Cyclic/Abstract/NZCyclic.v b/theories/Numbers/Cyclic/Abstract/NZCyclic.v index df9b83392..3f9b7b297 100644 --- a/theories/Numbers/Cyclic/Abstract/NZCyclic.v +++ b/theories/Numbers/Cyclic/Abstract/NZCyclic.v @@ -9,7 +9,8 @@ (************************************************************************) Require Export NZAxioms. -Require Import BigNumPrelude. +Require Import ZArith. +Require Import Zpow_facts. Require Import DoubleType. Require Import CyclicAxioms. @@ -139,6 +140,26 @@ rewrite 2 ZnZ.of_Z_correct; auto with zarith. symmetry; apply Zmod_small; auto with zarith. Qed. +Theorem Zbounded_induction : + (forall Q : Z -> Prop, forall b : Z, + Q 0 -> + (forall n, 0 <= n -> n < b - 1 -> Q n -> Q (n + 1)) -> + forall n, 0 <= n -> n < b -> Q n)%Z. +Proof. +intros Q b Q0 QS. +set (Q' := fun n => (n < b /\ Q n) \/ (b <= n)). +assert (H : forall n, 0 <= n -> Q' n). +apply natlike_rec2; unfold Q'. +destruct (Z.le_gt_cases b 0) as [H | H]. now right. left; now split. +intros n H IH. destruct IH as [[IH1 IH2] | IH]. +destruct (Z.le_gt_cases (b - 1) n) as [H1 | H1]. +right; auto with zarith. +left. split; [auto with zarith | now apply (QS n)]. +right; auto with zarith. +unfold Q' in *; intros n H1 H2. destruct (H n H1) as [[H3 H4] | H3]. +assumption. now apply Z.le_ngt in H3. +Qed. + Lemma B_holds : forall n : Z, 0 <= n < wB -> B n. Proof. intros n [H1 H2]. |