diff options
author | mohring <mohring@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2001-04-19 13:07:42 +0000 |
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committer | mohring <mohring@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2001-04-19 13:07:42 +0000 |
commit | cb9061d894d516e4607a9237813402d929384b26 (patch) | |
tree | 13137c2d2587c29483dbee0035ae1eab20f6342b /theories/Zarith/Zmisc.v | |
parent | 97271bd7c99f2a6de4b022af420f7a6050803492 (diff) |
remplace Zarith par ZArith
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@1625 85f007b7-540e-0410-9357-904b9bb8a0f7
Diffstat (limited to 'theories/Zarith/Zmisc.v')
-rw-r--r-- | theories/Zarith/Zmisc.v | 433 |
1 files changed, 0 insertions, 433 deletions
diff --git a/theories/Zarith/Zmisc.v b/theories/Zarith/Zmisc.v deleted file mode 100644 index 663fe535c..000000000 --- a/theories/Zarith/Zmisc.v +++ /dev/null @@ -1,433 +0,0 @@ -(***********************************************************************) -(* v * The Coq Proof Assistant / The Coq Development Team *) -(* <O___,, * INRIA-Rocquencourt & LRI-CNRS-Orsay *) -(* \VV/ *************************************************************) -(* // * This file is distributed under the terms of the *) -(* * GNU Lesser General Public License Version 2.1 *) -(***********************************************************************) - -(*i $Id$ i*) - -(********************************************************) -(* Module Zmisc.v : *) -(* Definitions et lemmes complementaires *) -(* Division euclidienne *) -(* Patrick Loiseleur, avril 1997 *) -(********************************************************) - -Require fast_integer. -Require zarith_aux. -Require auxiliary. -Require Zsyntax. -Require Bool. - -(********************************************************************** - Overview of the sections of this file : - - - logic : Logic complements. - - numbers : a few very simple lemmas for manipulating the - constructors [POS], [NEG], [ZERO] and [xI], [xO], [xH] - - registers : defining arrays of bits and their relation with integers. - - iter : the n-th iterate of a function is defined for n:nat and n:positive. - The two notions are identified and an invariant conservation theorem - is proved. - - recursors : Here a nat-like recursor is built. - - arith : lemmas about [< <= ?= + *] ... - -************************************************************************) - -Section logic. - -Lemma rename : (A:Set)(P:A->Prop)(x:A) ((y:A)(x=y)->(P y)) -> (P x). -Auto with arith. -Save. - -End logic. - -Section numbers. - -Definition entier_of_Z := [z:Z]Case z of Nul Pos Pos end. -Definition Z_of_entier := [x:entier]Case x of ZERO POS end. - -(*i Coercion Z_of_entier : entier >-> Z. i*) - -Lemma POS_xI : (p:positive) (POS (xI p))=`2*(POS p) + 1`. -Intro; Apply refl_equal. -Save. -Lemma POS_xO : (p:positive) (POS (xO p))=`2*(POS p)`. -Intro; Apply refl_equal. -Save. -Lemma NEG_xI : (p:positive) (NEG (xI p))=`2*(NEG p) - 1`. -Intro; Apply refl_equal. -Save. -Lemma NEG_xO : (p:positive) (NEG (xO p))=`2*(NEG p)`. -Intro; Apply refl_equal. -Save. - -Lemma POS_add : (p,p':positive)`(POS (add p p'))=(POS p)+(POS p')`. -Induction p; Induction p'; Simpl; Auto with arith. -Save. - -Lemma NEG_add : (p,p':positive)`(NEG (add p p'))=(NEG p)+(NEG p')`. -Induction p; Induction p'; Simpl; Auto with arith. -Save. - -Definition Zle_bool := [x,y:Z]Case `x ?= y` of true true false end. -Definition Zge_bool := [x,y:Z]Case `x ?= y` of true false true end. -Definition Zlt_bool := [x,y:Z]Case `x ?= y` of false true false end. -Definition Zgt_bool := [x,y:Z]Case ` x ?= y` of false false true end. -Definition Zeq_bool := [x,y:Z]Cases `x ?= y` of EGAL => true | _ => false end. -Definition Zneq_bool := [x,y:Z]Cases `x ?= y` of EGAL =>false | _ => true end. - -End numbers. - -Section iterate. - -(* l'itere n-ieme d'une fonction f*) -Fixpoint iter_nat[n:nat] : (A:Set)(f:A->A)A->A := - [A:Set][f:A->A][x:A] - Cases n of - O => x - | (S n') => (f (iter_nat n' A f x)) - end. - -Fixpoint iter_pos[n:positive] : (A:Set)(f:A->A)A->A := - [A:Set][f:A->A][x:A] - Cases n of - xH => (f x) - | (xO n') => (iter_pos n' A f (iter_pos n' A f x)) - | (xI n') => (f (iter_pos n' A f (iter_pos n' A f x))) - end. - -Definition iter := - [n:Z][A:Set][f:A->A][x:A]Cases n of - ZERO => x - | (POS p) => (iter_pos p A f x) - | (NEG p) => x - end. - -Theorem iter_nat_plus : - (n,m:nat)(A:Set)(f:A->A)(x:A) - (iter_nat (plus n m) A f x)=(iter_nat n A f (iter_nat m A f x)). - -Induction n; -[ Simpl; Auto with arith -| Intros; Simpl; Apply f_equal with f:=f; Apply H -]. -Save. - -Theorem iter_convert : (n:positive)(A:Set)(f:A->A)(x:A) - (iter_pos n A f x) = (iter_nat (convert n) A f x). - -Induction n; -[ Intros; Simpl; Rewrite -> (H A f x); - Rewrite -> (H A f (iter_nat (convert p) A f x)); - Rewrite -> (ZL6 p); Symmetry; Apply f_equal with f:=f; - Apply iter_nat_plus -| Intros; Unfold convert; Simpl; Rewrite -> (H A f x); - Rewrite -> (H A f (iter_nat (convert p) A f x)); - Rewrite -> (ZL6 p); Symmetry; - Apply iter_nat_plus -| Simpl; Auto with arith -]. -Save. - -Theorem iter_pos_add : - (n,m:positive)(A:Set)(f:A->A)(x:A) - (iter_pos (add n m) A f x)=(iter_pos n A f (iter_pos m A f x)). - -Intros. -Rewrite -> (iter_convert m A f x). -Rewrite -> (iter_convert n A f (iter_nat (convert m) A f x)). -Rewrite -> (iter_convert (add n m) A f x). -Rewrite -> (convert_add n m). -Apply iter_nat_plus. -Save. - -(* Preservation of invariants : if f : A->A preserves the invariant Inv, - then the iterates of f also preserve it. *) - -Theorem iter_nat_invariant : - (n:nat)(A:Set)(f:A->A)(Inv:A->Prop) - ((x:A)(Inv x)->(Inv (f x)))->(x:A)(Inv x)->(Inv (iter_nat n A f x)). -Induction n; Intros; -[ Trivial with arith -| Simpl; Apply H0 with x:=(iter_nat n0 A f x); Apply H; Trivial with arith]. -Save. - -Theorem iter_pos_invariant : - (n:positive)(A:Set)(f:A->A)(Inv:A->Prop) - ((x:A)(Inv x)->(Inv (f x)))->(x:A)(Inv x)->(Inv (iter_pos n A f x)). -Intros; Rewrite iter_convert; Apply iter_nat_invariant; Trivial with arith. -Save. - -End iterate. - - -Section arith. - -Lemma ZERO_le_POS : (p:positive) `0 <= (POS p)`. -Intro; Unfold Zle; Unfold Zcompare; Discriminate. -Save. - -Lemma POS_gt_ZERO : (p:positive) `(POS p) > 0`. -Intro; Unfold Zgt; Simpl; Trivial with arith. -Save. - -Lemma Zlt_ZERO_pred_le_ZERO : (x:Z) `0 < x` -> `0 <= (Zpred x)`. -Intros. -Rewrite (Zs_pred x) in H. -Apply Zgt_S_le. -Apply Zlt_gt. -Assumption. -Save. - -(* Zeven, Zodd, Zdiv2 and their related properties *) - -Definition Zeven := - [z:Z]Cases z of ZERO => True - | (POS (xO _)) => True - | (NEG (xO _)) => True - | _ => False - end. - -Definition Zodd := - [z:Z]Cases z of (POS xH) => True - | (NEG xH) => True - | (POS (xI _)) => True - | (NEG (xI _)) => True - | _ => False - end. - -Definition Zeven_bool := - [z:Z]Cases z of ZERO => true - | (POS (xO _)) => true - | (NEG (xO _)) => true - | _ => false - end. - -Definition Zodd_bool := - [z:Z]Cases z of ZERO => false - | (POS (xO _)) => false - | (NEG (xO _)) => false - | _ => true - end. - -Lemma Zeven_odd_dec : (z:Z) { (Zeven z) }+{ (Zodd z) }. -Proof. - Intro z. Case z; - [ Left; Compute; Trivial - | Intro p; Case p; Intros; - (Right; Compute; Exact I) Orelse (Left; Compute; Exact I) - | Intro p; Case p; Intros; - (Right; Compute; Exact I) Orelse (Left; Compute; Exact I) ]. - (*i was - Realizer Zeven_bool. - Repeat Program; Compute; Trivial. - i*) -Save. - -Lemma Zeven_dec : (z:Z) { (Zeven z) }+{ ~(Zeven z) }. -Proof. - Intro z. Case z; - [ Left; Compute; Trivial - | Intro p; Case p; Intros; - (Left; Compute; Exact I) Orelse (Right; Compute; Trivial) - | Intro p; Case p; Intros; - (Left; Compute; Exact I) Orelse (Right; Compute; Trivial) ]. - (*i was - Realizer Zeven_bool. - Repeat Program; Compute; Trivial. - i*) -Save. - -Lemma Zodd_dec : (z:Z) { (Zodd z) }+{ ~(Zodd z) }. -Proof. - Intro z. Case z; - [ Right; Compute; Trivial - | Intro p; Case p; Intros; - (Left; Compute; Exact I) Orelse (Right; Compute; Trivial) - | Intro p; Case p; Intros; - (Left; Compute; Exact I) Orelse (Right; Compute; Trivial) ]. - (*i was - Realizer Zodd_bool. - Repeat Program; Compute; Trivial. - i*) -Save. - -Lemma Zeven_not_Zodd : (z:Z)(Zeven z) -> ~(Zodd z). -Proof. - Destruct z; [ Idtac | Destruct p | Destruct p ]; Compute; Trivial. -Save. - -Lemma Zodd_not_Zeven : (z:Z)(Zodd z) -> ~(Zeven z). -Proof. - Destruct z; [ Idtac | Destruct p | Destruct p ]; Compute; Trivial. -Save. - -Hints Unfold Zeven Zodd : zarith. - -(* Zdiv2 is defined on all Z, but notice that for odd negative integers - * it is not the euclidean quotient: in that case we have n = 2*(n/2)-1 - *) - -Definition Zdiv2_pos := - [z:positive]Cases z of xH => xH - | (xO p) => p - | (xI p) => p - end. - -Definition Zdiv2 := - [z:Z]Cases z of ZERO => ZERO - | (POS xH) => ZERO - | (POS p) => (POS (Zdiv2_pos p)) - | (NEG xH) => ZERO - | (NEG p) => (NEG (Zdiv2_pos p)) - end. - -Lemma Zeven_div2 : (x:Z) (Zeven x) -> `x = 2*(Zdiv2 x)`. -Proof. -Destruct x. -Auto with arith. -Destruct p; Auto with arith. -Intros. Absurd (Zeven (POS (xI p0))); Red; Auto with arith. -Intros. Absurd (Zeven `1`); Red; Auto with arith. -Destruct p; Auto with arith. -Intros. Absurd (Zeven (NEG (xI p0))); Red; Auto with arith. -Intros. Absurd (Zeven `-1`); Red; Auto with arith. -Save. - -Lemma Zodd_div2 : (x:Z) `x >= 0` -> (Zodd x) -> `x = 2*(Zdiv2 x)+1`. -Proof. -Destruct x. -Intros. Absurd (Zodd `0`); Red; Auto with arith. -Destruct p; Auto with arith. -Intros. Absurd (Zodd (POS (xO p0))); Red; Auto with arith. -Intros. Absurd `(NEG p) >= 0`; Red; Auto with arith. -Save. - -Lemma Z_modulo_2 : (x:Z) `x >= 0` -> { y:Z | `x=2*y` }+{ y:Z | `x=2*y+1` }. -Proof. -Intros x Hx. -Elim (Zeven_odd_dec x); Intro. -Left. Split with (Zdiv2 x). Exact (Zeven_div2 x a). -Right. Split with (Zdiv2 x). Exact (Zodd_div2 x Hx b). -Save. - -(* Very simple *) -Lemma Zminus_Zplus_compatible : - (x,y,n:Z) `(x+n) - (y+n) = x - y`. -Intros. -Unfold Zminus. -Rewrite -> Zopp_Zplus. -Rewrite -> (Zplus_sym (Zopp y) (Zopp n)). -Rewrite -> Zplus_assoc. -Rewrite <- (Zplus_assoc x n (Zopp n)). -Rewrite -> (Zplus_inverse_r n). -Rewrite <- Zplus_n_O. -Reflexivity. -Save. - -(* Decompose an egality between two ?= relations into 3 implications *) -Theorem Zcompare_egal_dec : - (x1,y1,x2,y2:Z) - (`x1 < y1`->`x2 < y2`) - ->(`x1 ?= y1`=EGAL -> `x2 ?= y2`=EGAL) - ->(`x1 > y1`->`x2 > y2`)->`x1 ?= y1`=`x2 ?= y2`. -Intros x1 y1 x2 y2. -Unfold Zgt; Unfold Zlt; -Case `x1 ?= y1`; Case `x2 ?= y2`; Auto with arith; Symmetry; Auto with arith. -Save. - -Theorem Zcompare_elim : - (c1,c2,c3:Prop)(x,y:Z) - ((x=y) -> c1) ->(`x < y` -> c2) ->(`x > y`-> c3) - -> Case `x ?= y`of c1 c2 c3 end. - -Intros. -Apply rename with x:=`x ?= y`; Intro r; Elim r; -[ Intro; Apply H; Apply (let (h1, h2)=(Zcompare_EGAL x y) in h1); Assumption -| Unfold Zlt in H0; Assumption -| Unfold Zgt in H1; Assumption ]. -Save. - -Lemma Zcompare_x_x : (x:Z) `x ?= x` = EGAL. -Intro; Apply Case (Zcompare_EGAL x x) of [h1,h2: ?]h2 end. -Apply refl_equal. -Save. - -Lemma Zlt_not_eq : (x,y:Z)`x < y` -> ~x=y. -Proof. -Intros. -Unfold Zlt in H. -Unfold not. -Intro. -Generalize (proj2 ? ? (Zcompare_EGAL x y) H0). -Intro. -Rewrite H1 in H. -Discriminate H. -Save. - -Lemma Zcompare_eq_case : - (c1,c2,c3:Prop)(x,y:Z) c1 -> x=y -> (Case `x ?= y` of c1 c2 c3 end). -Intros. -Rewrite -> (Case (Zcompare_EGAL x y) of [h1,h2: ?]h2 end H0). -Assumption. -Save. - -(* Four very basic lemmas about Zle, Zlt, Zge, Zgt *) -Lemma Zle_Zcompare : - (x,y:Z)`x <= y` -> Case `x ?= y` of True True False end. -Intros x y; Unfold Zle; Elim `x ?=y`; Auto with arith. -Save. - -Lemma Zlt_Zcompare : - (x,y:Z)`x < y` -> Case `x ?= y` of False True False end. -Intros x y; Unfold Zlt; Elim `x ?=y`; Intros; Discriminate Orelse Trivial with arith. -Save. - -Lemma Zge_Zcompare : - (x,y:Z)` x >= y`-> Case `x ?= y` of True False True end. -Intros x y; Unfold Zge; Elim `x ?=y`; Auto with arith. -Save. - -Lemma Zgt_Zcompare : - (x,y:Z)`x > y` -> Case `x ?= y` of False False True end. -Intros x y; Unfold Zgt; Elim `x ?= y`; Intros; Discriminate Orelse Trivial with arith. -Save. - -(* Lemmas about Zmin *) - -Lemma Zmin_plus : (x,y,n:Z) `(Zmin (x+n)(y+n))=(Zmin x y)+n`. -Intros; Unfold Zmin. -Rewrite (Zplus_sym x n); -Rewrite (Zplus_sym y n); -Rewrite (Zcompare_Zplus_compatible x y n). -Case `x ?= y`; Apply Zplus_sym. -Save. - -(* Lemmas about absolu *) - -Lemma absolu_lt : (x,y:Z) `0 <= x < y` -> (lt (absolu x) (absolu y)). -Proof. -Intros x y. Case x; Simpl. Case y; Simpl. - -Intro. Absurd `0 < 0`. Compute. Intro H0. Discriminate H0. Intuition. -Intros. Elim (ZL4 p). Intros. Rewrite H0. Auto with arith. -Intros. Elim (ZL4 p). Intros. Rewrite H0. Auto with arith. - -Case y; Simpl. -Intros. Absurd `(POS p) < 0`. Compute. Intro H0. Discriminate H0. Intuition. -Intros. Change (gt (convert p) (convert p0)). -Apply compare_convert_SUPERIEUR. -Elim H; Auto with arith. Intro. Exact (ZC2 p0 p). - -Intros. Absurd `(POS p0) < (NEG p)`. -Compute. Intro H0. Discriminate H0. Intuition. - -Intros. Absurd `0 <= (NEG p)`. Compute. Auto with arith. Intuition. -Save. - - -End arith. - |