diff options
| author | Enrico Tassi | 2015-11-05 11:36:58 +0100 |
|---|---|---|
| committer | Enrico Tassi | 2015-11-05 16:26:24 +0100 |
| commit | 14c9a3a752e8c21b239ff0800089271c5a5ddfb2 (patch) | |
| tree | 8f7095e1702d5ad56003f8d87df84786902dfec0 /mathcomp/basic/finfun.v | |
| parent | 35124d2e255e5f88d99ddc65361d6997b0a2b751 (diff) | |
merge basic/ into ssreflect/
Diffstat (limited to 'mathcomp/basic/finfun.v')
| -rw-r--r-- | mathcomp/basic/finfun.v | 305 |
1 files changed, 0 insertions, 305 deletions
diff --git a/mathcomp/basic/finfun.v b/mathcomp/basic/finfun.v deleted file mode 100644 index ca148e2..0000000 --- a/mathcomp/basic/finfun.v +++ /dev/null @@ -1,305 +0,0 @@ -(* (c) Copyright 2006-2015 Microsoft Corporation and Inria. *) -(* Distributed under the terms of CeCILL-B. *) -Require Import mathcomp.ssreflect.ssreflect. -From mathcomp -Require Import ssrfun ssrbool eqtype ssrnat seq choice fintype tuple. - -(******************************************************************************) -(* This file implements a type for functions with a finite domain: *) -(* {ffun aT -> rT} where aT should have a finType structure. *) -(* Any eqType, choiceType, countType and finType structures on rT extend to *) -(* {ffun aT -> rT} as Leibnitz equality and extensional equalities coincide. *) -(* (T ^ n)%type is notation for {ffun 'I_n -> T}, which is isomorphic *) -(* ot n.-tuple T. *) -(* For f : {ffun aT -> rT}, we define *) -(* f x == the image of x under f (f coerces to a CiC function) *) -(* fgraph f == the graph of f, i.e., the #|aT|.-tuple rT of the *) -(* values of f over enum aT. *) -(* finfun lam == the f such that f =1 lam; this is the RECOMMENDED *) -(* interface to build an element of {ffun aT -> rT}. *) -(* [ffun x => expr] == finfun (fun x => expr) *) -(* [ffun => expr] == finfun (fun _ => expr) *) -(* f \in ffun_on R == the range of f is a subset of R *) -(* f \in family F == f belongs to the family F (f x \in F x for all x) *) -(* y.-support f == the y-support of f, i.e., [pred x | f x != y]. *) -(* Thus, y.-support f \subset D means f has y-support D. *) -(* We will put Notation support := 0.-support in ssralg. *) -(* f \in pffun_on y D R == f is a y-partial function from D to R: *) -(* f has y-support D and f x \in R for all x \in D. *) -(* f \in pfamily y D F == f belongs to the y-partial family from D to F: *) -(* f has y-support D and f x \in F x for all x \in D. *) -(******************************************************************************) - -Set Implicit Arguments. -Unset Strict Implicit. -Unset Printing Implicit Defensive. - -Section Def. - -Variables (aT : finType) (rT : Type). - -Inductive finfun_type : predArgType := Finfun of #|aT|.-tuple rT. - -Definition finfun_of of phant (aT -> rT) := finfun_type. - -Identity Coercion type_of_finfun : finfun_of >-> finfun_type. - -Definition fgraph f := let: Finfun t := f in t. - -Canonical finfun_subType := Eval hnf in [newType for fgraph]. - -End Def. - -Notation "{ 'ffun' fT }" := (finfun_of (Phant fT)) - (at level 0, format "{ 'ffun' '[hv' fT ']' }") : type_scope. -Definition finexp_domFinType n := ordinal_finType n. -Notation "T ^ n" := (@finfun_of (finexp_domFinType n) T (Phant _)) : type_scope. - -Notation Local fun_of_fin_def := - (fun aT rT f x => tnth (@fgraph aT rT f) (enum_rank x)). - -Notation Local finfun_def := (fun aT rT f => @Finfun aT rT (codom_tuple f)). - -Module Type FunFinfunSig. -Parameter fun_of_fin : forall aT rT, finfun_type aT rT -> aT -> rT. -Parameter finfun : forall (aT : finType) rT, (aT -> rT) -> {ffun aT -> rT}. -Axiom fun_of_finE : fun_of_fin = fun_of_fin_def. -Axiom finfunE : finfun = finfun_def. -End FunFinfunSig. - -Module FunFinfun : FunFinfunSig. -Definition fun_of_fin := fun_of_fin_def. -Definition finfun := finfun_def. -Lemma fun_of_finE : fun_of_fin = fun_of_fin_def. Proof. by []. Qed. -Lemma finfunE : finfun = finfun_def. Proof. by []. Qed. -End FunFinfun. - -Notation fun_of_fin := FunFinfun.fun_of_fin. -Notation finfun := FunFinfun.finfun. -Coercion fun_of_fin : finfun_type >-> Funclass. -Canonical fun_of_fin_unlock := Unlockable FunFinfun.fun_of_finE. -Canonical finfun_unlock := Unlockable FunFinfun.finfunE. - -Notation "[ 'ffun' x : aT => F ]" := (finfun (fun x : aT => F)) - (at level 0, x ident, only parsing) : fun_scope. - -Notation "[ 'ffun' : aT => F ]" := (finfun (fun _ : aT => F)) - (at level 0, only parsing) : fun_scope. - -Notation "[ 'ffun' x => F ]" := [ffun x : _ => F] - (at level 0, x ident, format "[ 'ffun' x => F ]") : fun_scope. - -Notation "[ 'ffun' => F ]" := [ffun : _ => F] - (at level 0, format "[ 'ffun' => F ]") : fun_scope. - -(* Helper for defining notation for function families. *) -Definition fmem aT rT (pT : predType rT) (f : aT -> pT) := [fun x => mem (f x)]. - -(* Lemmas on the correspondance between finfun_type and CiC functions. *) -Section PlainTheory. - -Variables (aT : finType) (rT : Type). -Notation fT := {ffun aT -> rT}. -Implicit Types (f : fT) (R : pred rT). - -Canonical finfun_of_subType := Eval hnf in [subType of fT]. - -Lemma tnth_fgraph f i : tnth (fgraph f) i = f (enum_val i). -Proof. by rewrite [@fun_of_fin]unlock enum_valK. Qed. - -Lemma ffunE (g : aT -> rT) : finfun g =1 g. -Proof. -move=> x; rewrite [@finfun]unlock unlock tnth_map. -by rewrite -[tnth _ _]enum_val_nth enum_rankK. -Qed. - -Lemma fgraph_codom f : fgraph f = codom_tuple f. -Proof. -apply: eq_from_tnth => i; rewrite [@fun_of_fin]unlock tnth_map. -by congr tnth; rewrite -[tnth _ _]enum_val_nth enum_valK. -Qed. - -Lemma codom_ffun f : codom f = val f. -Proof. by rewrite /= fgraph_codom. Qed. - -Lemma ffunP f1 f2 : f1 =1 f2 <-> f1 = f2. -Proof. -split=> [eq_f12 | -> //]; do 2!apply: val_inj => /=. -by rewrite !fgraph_codom /= (eq_codom eq_f12). -Qed. - -Lemma ffunK : cancel (@fun_of_fin aT rT) (@finfun aT rT). -Proof. by move=> f; apply/ffunP/ffunE. Qed. - -Definition family_mem mF := [pred f : fT | [forall x, in_mem (f x) (mF x)]]. - -Lemma familyP (pT : predType rT) (F : aT -> pT) f : - reflect (forall x, f x \in F x) (f \in family_mem (fmem F)). -Proof. exact: forallP. Qed. - -Definition ffun_on_mem mR := family_mem (fun _ => mR). - -Lemma ffun_onP R f : reflect (forall x, f x \in R) (f \in ffun_on_mem (mem R)). -Proof. exact: forallP. Qed. - -End PlainTheory. - -Notation family F := (family_mem (fun_of_simpl (fmem F))). -Notation ffun_on R := (ffun_on_mem _ (mem R)). - -Implicit Arguments familyP [aT rT pT F f]. -Implicit Arguments ffun_onP [aT rT R f]. - -(*****************************************************************************) - -Lemma nth_fgraph_ord T n (x0 : T) (i : 'I_n) f : nth x0 (fgraph f) i = f i. -Proof. -by rewrite -{2}(enum_rankK i) -tnth_fgraph (tnth_nth x0) enum_rank_ord. -Qed. - -Section Support. - -Variables (aT : Type) (rT : eqType). - -Definition support_for y (f : aT -> rT) := [pred x | f x != y]. - -Lemma supportE x y f : (x \in support_for y f) = (f x != y). Proof. by []. Qed. - -End Support. - -Notation "y .-support" := (support_for y) - (at level 2, format "y .-support") : fun_scope. - -Section EqTheory. - -Variables (aT : finType) (rT : eqType). -Notation fT := {ffun aT -> rT}. -Implicit Types (y : rT) (D : pred aT) (R : pred rT) (f : fT). - -Lemma supportP y D g : - reflect (forall x, x \notin D -> g x = y) (y.-support g \subset D). -Proof. -by apply: (iffP subsetP) => Dg x; [apply: contraNeq | apply: contraR] => /Dg->. -Qed. - -Definition finfun_eqMixin := - Eval hnf in [eqMixin of finfun_type aT rT by <:]. -Canonical finfun_eqType := Eval hnf in EqType _ finfun_eqMixin. -Canonical finfun_of_eqType := Eval hnf in [eqType of fT]. - -Definition pfamily_mem y mD (mF : aT -> mem_pred rT) := - family (fun i : aT => if in_mem i mD then pred_of_simpl (mF i) else pred1 y). - -Lemma pfamilyP (pT : predType rT) y D (F : aT -> pT) f : - reflect (y.-support f \subset D /\ {in D, forall x, f x \in F x}) - (f \in pfamily_mem y (mem D) (fmem F)). -Proof. -apply: (iffP familyP) => [/= f_pfam | [/supportP f_supp f_fam] x]. - split=> [|x Ax]; last by have:= f_pfam x; rewrite Ax. - by apply/subsetP=> x; case: ifP (f_pfam x) => //= _ fx0 /negP[]. -by case: ifPn => Ax /=; rewrite inE /= (f_fam, f_supp). -Qed. - -Definition pffun_on_mem y mD mR := pfamily_mem y mD (fun _ => mR). - -Lemma pffun_onP y D R f : - reflect (y.-support f \subset D /\ {subset image f D <= R}) - (f \in pffun_on_mem y (mem D) (mem R)). -Proof. -apply: (iffP (pfamilyP y D (fun _ => R) f)) => [] [-> f_fam]; split=> //. - by move=> _ /imageP[x Ax ->]; apply: f_fam. -by move=> x Ax; apply: f_fam; apply/imageP; exists x. -Qed. - -End EqTheory. -Canonical exp_eqType (T : eqType) n := [eqType of T ^ n]. - -Implicit Arguments supportP [aT rT y D g]. -Notation pfamily y D F := (pfamily_mem y (mem D) (fun_of_simpl (fmem F))). -Notation pffun_on y D R := (pffun_on_mem y (mem D) (mem R)). - -Definition finfun_choiceMixin aT (rT : choiceType) := - [choiceMixin of finfun_type aT rT by <:]. -Canonical finfun_choiceType aT rT := - Eval hnf in ChoiceType _ (finfun_choiceMixin aT rT). -Canonical finfun_of_choiceType (aT : finType) (rT : choiceType) := - Eval hnf in [choiceType of {ffun aT -> rT}]. -Canonical exp_choiceType (T : choiceType) n := [choiceType of T ^ n]. - -Definition finfun_countMixin aT (rT : countType) := - [countMixin of finfun_type aT rT by <:]. -Canonical finfun_countType aT (rT : countType) := - Eval hnf in CountType _ (finfun_countMixin aT rT). -Canonical finfun_of_countType (aT : finType) (rT : countType) := - Eval hnf in [countType of {ffun aT -> rT}]. -Canonical finfun_subCountType aT (rT : countType) := - Eval hnf in [subCountType of finfun_type aT rT]. -Canonical finfun_of_subCountType (aT : finType) (rT : countType) := - Eval hnf in [subCountType of {ffun aT -> rT}]. - -(*****************************************************************************) - -Section FinTheory. - -Variables aT rT : finType. -Notation fT := {ffun aT -> rT}. -Notation ffT := (finfun_type aT rT). -Implicit Types (D : pred aT) (R : pred rT) (F : aT -> pred rT). - -Definition finfun_finMixin := [finMixin of ffT by <:]. -Canonical finfun_finType := Eval hnf in FinType ffT finfun_finMixin. -Canonical finfun_subFinType := Eval hnf in [subFinType of ffT]. -Canonical finfun_of_finType := Eval hnf in [finType of fT for finfun_finType]. -Canonical finfun_of_subFinType := Eval hnf in [subFinType of fT]. - -Lemma card_pfamily y0 D F : - #|pfamily y0 D F| = foldr muln 1 [seq #|F x| | x in D]. -Proof. -rewrite /image_mem; transitivity #|pfamily y0 (enum D) F|. - by apply/eq_card=> f; apply/eq_forallb=> x /=; rewrite mem_enum. -elim: {D}(enum D) (enum_uniq D) => /= [_|x0 s IHs /andP[s'x0 /IHs<-{IHs}]]. - apply: eq_card1 [ffun=> y0] _ _ => f. - apply/familyP/eqP=> [y0_f|-> x]; last by rewrite ffunE inE. - by apply/ffunP=> x; rewrite ffunE (eqP (y0_f x)). -pose g (xf : rT * fT) := finfun [eta xf.2 with x0 |-> xf.1]. -have gK: cancel (fun f : fT => (f x0, g (y0, f))) g. - by move=> f; apply/ffunP=> x; do !rewrite ffunE /=; case: eqP => // ->. -rewrite -cardX -(card_image (can_inj gK)); apply: eq_card => [] [y f] /=. -apply/imageP/andP=> [[f0 /familyP/=Ff0] [{f}-> ->]| [Fy /familyP/=Ff]]. - split; first by have:= Ff0 x0; rewrite /= mem_head. - apply/familyP=> x; have:= Ff0 x; rewrite ffunE inE /=. - by case: eqP => //= -> _; rewrite ifN ?inE. -exists (g (y, f)). - by apply/familyP=> x; have:= Ff x; rewrite ffunE /= inE; case: eqP => // ->. -congr (_, _); last apply/ffunP=> x; do !rewrite ffunE /= ?eqxx //. -by case: eqP => // ->{x}; apply/eqP; have:= Ff x0; rewrite ifN. -Qed. - -Lemma card_family F : #|family F| = foldr muln 1 [seq #|F x| | x : aT]. -Proof. -have [y0 _ | rT0] := pickP rT; first exact: (card_pfamily y0 aT). -rewrite /image_mem; case DaT: (enum aT) => [{rT0}|x0 e] /=; last first. - by rewrite !eq_card0 // => [f | y]; [have:= rT0 (f x0) | have:= rT0 y]. -have{DaT} no_aT P (x : aT) : P by have:= mem_enum aT x; rewrite DaT. -apply: eq_card1 [ffun x => no_aT rT x] _ _ => f. -by apply/familyP/eqP=> _; [apply/ffunP | ] => x; apply: no_aT. -Qed. - -Lemma card_pffun_on y0 D R : #|pffun_on y0 D R| = #|R| ^ #|D|. -Proof. -rewrite (cardE D) card_pfamily /image_mem. -by elim: (enum D) => //= _ e ->; rewrite expnS. -Qed. - -Lemma card_ffun_on R : #|ffun_on R| = #|R| ^ #|aT|. -Proof. -rewrite card_family /image_mem cardT. -by elim: (enum aT) => //= _ e ->; rewrite expnS. -Qed. - -Lemma card_ffun : #|fT| = #|rT| ^ #|aT|. -Proof. by rewrite -card_ffun_on; apply/esym/eq_card=> f; apply/forallP. Qed. - -End FinTheory. -Canonical exp_finType (T : finType) n := [finType of T ^ n]. - |
