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From iris.algebra Require Export big_op.
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From iris.bi Require Import derived_laws_sbi plainly.
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From stdpp Require Import countable fin_collections functions.
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Set Default Proof Using "Type".
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Import interface.bi derived_laws_bi.bi derived_laws_sbi.bi.
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(** A version of the separating big operator that ranges over two lists. This
version also ensures that both lists have the same length. Although this version
can be defined in terms of the unary using a [zip] (see [big_sepL2_alt]), we do
not define it that way to get better computational behavior (for [simpl]). *)
Fixpoint big_sepL2 {PROP : bi} {A B}
    (Φ : nat  A  B  PROP) (l1 : list A) (l2 : list B) : PROP :=
  match l1, l2 with
  | [], [] => emp
  | x1 :: l1, x2 :: l2 => Φ 0 x1 x2  big_sepL2 (λ n, Φ (S n)) l1 l2
  | _, _ => False
  end%I.
Instance: Params (@big_sepL2) 3.
Arguments big_sepL2 {PROP A B} _ !_ !_ /.
Typeclasses Opaque big_sepL2.

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(* Notations *)
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Notation "'[∗' 'list]' k ↦ x ∈ l , P" :=
  (big_opL bi_sep (λ k x, P) l) : bi_scope.
Notation "'[∗' 'list]' x ∈ l , P" :=
  (big_opL bi_sep (λ _ x, P) l) : bi_scope.

Notation "'[∗]' Ps" := (big_opL bi_sep (λ _ x, x) Ps) : bi_scope.

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Notation "'[∗' 'list]' k ↦ x1 ; x2 ∈ l1 ; l2 , P" :=
  (big_sepL2 (λ k x1 x2, P) l1 l2) : bi_scope.
Notation "'[∗' 'list]' x1 ; x2 ∈ l1 ; l2 , P" :=
  (big_sepL2 (λ _ x1 x2, P) l1 l2) : bi_scope.

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Notation "'[∧' 'list]' k ↦ x ∈ l , P" :=
  (big_opL bi_and (λ k x, P) l) : bi_scope.
Notation "'[∧' 'list]' x ∈ l , P" :=
  (big_opL bi_and (λ _ x, P) l) : bi_scope.

Notation "'[∧]' Ps" := (big_opL bi_and (λ _ x, x) Ps) : bi_scope.

Notation "'[∗' 'map]' k ↦ x ∈ m , P" := (big_opM bi_sep (λ k x, P) m) : bi_scope.
Notation "'[∗' 'map]' x ∈ m , P" := (big_opM bi_sep (λ _ x, P) m) : bi_scope.

Notation "'[∗' 'set]' x ∈ X , P" := (big_opS bi_sep (λ x, P) X) : bi_scope.

Notation "'[∗' 'mset]' x ∈ X , P" := (big_opMS bi_sep (λ x, P) X) : bi_scope.
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(** * Properties *)
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Section bi_big_op.
Context {PROP : bi}.
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Implicit Types P Q : PROP.
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Implicit Types Ps Qs : list PROP.
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Implicit Types A : Type.

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(** ** Big ops over lists *)
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Section sep_list.
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  Context {A : Type}.
  Implicit Types l : list A.
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  Implicit Types Φ Ψ : nat  A  PROP.
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  Lemma big_sepL_nil Φ : ([ list] ky  nil, Φ k y)  emp.
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  Proof. done. Qed.
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  Lemma big_sepL_nil' `{BiAffine PROP} P Φ : P  [ list] ky  nil, Φ k y.
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  Proof. apply (affine _). Qed.
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  Lemma big_sepL_cons Φ x l :
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    ([ list] ky  x :: l, Φ k y)  Φ 0 x  [ list] ky  l, Φ (S k) y.
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  Proof. by rewrite big_opL_cons. Qed.
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  Lemma big_sepL_singleton Φ x : ([ list] ky  [x], Φ k y)  Φ 0 x.
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  Proof. by rewrite big_opL_singleton. Qed.
  Lemma big_sepL_app Φ l1 l2 :
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    ([ list] ky  l1 ++ l2, Φ k y)
     ([ list] ky  l1, Φ k y)  ([ list] ky  l2, Φ (length l1 + k) y).
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  Proof. by rewrite big_opL_app. Qed.

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  Lemma big_sepL_mono Φ Ψ l :
    ( k y, l !! k = Some y  Φ k y  Ψ k y) 
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    ([ list] k  y  l, Φ k y)  [ list] k  y  l, Ψ k y.
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  Proof. apply big_opL_forall; apply _. Qed.
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  Lemma big_sepL_proper Φ Ψ l :
    ( k y, l !! k = Some y  Φ k y  Ψ k y) 
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    ([ list] k  y  l, Φ k y)  ([ list] k  y  l, Ψ k y).
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  Proof. apply big_opL_proper. Qed.
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  Lemma big_sepL_submseteq `{BiAffine PROP} (Φ : A  PROP) l1 l2 :
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    l1 + l2  ([ list] y  l2, Φ y)  [ list] y  l1, Φ y.
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  Proof.
    intros [l ->]%submseteq_Permutation. by rewrite big_sepL_app sep_elim_l.
  Qed.
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  Global Instance big_sepL_mono' :
    Proper (pointwise_relation _ (pointwise_relation _ ()) ==> (=) ==> ())
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           (big_opL (@bi_sep PROP) (A:=A)).
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  Proof. intros f g Hf m ? <-. apply big_opL_forall; apply _ || intros; apply Hf. Qed.
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  Global Instance big_sepL_id_mono' :
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    Proper (Forall2 () ==> ()) (big_opL (@bi_sep PROP) (λ _ P, P)).
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  Proof. by induction 1 as [|P Q Ps Qs HPQ ? IH]; rewrite /= ?HPQ ?IH. Qed.
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  Lemma big_sepL_emp l : ([ list] ky  l, emp) @{PROP} emp.
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  Proof. by rewrite big_opL_unit. Qed.

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  Lemma big_sepL_lookup_acc Φ l i x :
    l !! i = Some x 
    ([ list] ky  l, Φ k y)  Φ i x  (Φ i x - ([ list] ky  l, Φ k y)).
  Proof.
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    intros Hli. rewrite -(take_drop_middle l i x) // big_sepL_app /=.
    rewrite Nat.add_0_r take_length_le; eauto using lookup_lt_Some, Nat.lt_le_incl.
    rewrite assoc -!(comm _ (Φ _ _)) -assoc. by apply sep_mono_r, wand_intro_l.
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  Qed.

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  Lemma big_sepL_lookup Φ l i x `{!Absorbing (Φ i x)} :
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    l !! i = Some x  ([ list] ky  l, Φ k y)  Φ i x.
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  Proof. intros. rewrite big_sepL_lookup_acc //. by rewrite sep_elim_l. Qed.
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  Lemma big_sepL_elem_of (Φ : A  PROP) l x `{!Absorbing (Φ x)} :
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    x  l  ([ list] y  l, Φ y)  Φ x.
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  Proof.
    intros [i ?]%elem_of_list_lookup; eauto using (big_sepL_lookup (λ _, Φ)).
  Qed.
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  Lemma big_sepL_fmap {B} (f : A  B) (Φ : nat  B  PROP) l :
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    ([ list] ky  f <$> l, Φ k y)  ([ list] ky  l, Φ k (f y)).
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  Proof. by rewrite big_opL_fmap. Qed.
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  Lemma big_sepL_sepL Φ Ψ l :
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    ([ list] kx  l, Φ k x  Ψ k x)
     ([ list] kx  l, Φ k x)  ([ list] kx  l, Ψ k x).
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  Proof. by rewrite big_opL_opL. Qed.
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  Lemma big_sepL_and Φ Ψ l :
    ([ list] kx  l, Φ k x  Ψ k x)
     ([ list] kx  l, Φ k x)  ([ list] kx  l, Ψ k x).
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  Proof. auto using and_intro, big_sepL_mono, and_elim_l, and_elim_r. Qed.
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  Lemma big_sepL_persistently `{BiAffine PROP} Φ l :
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    <pers> ([ list] kx  l, Φ k x)  [ list] kx  l, <pers> (Φ k x).
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  Proof. apply (big_opL_commute _). Qed.
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  Lemma big_sepL_forall `{BiAffine PROP} Φ l :
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    ( k x, Persistent (Φ k x)) 
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    ([ list] kx  l, Φ k x)  ( k x, l !! k = Some x  Φ k x).
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  Proof.
    intros HΦ. apply (anti_symm _).
    { apply forall_intro=> k; apply forall_intro=> x.
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      apply impl_intro_l, pure_elim_l=> ?; by apply: big_sepL_lookup. }
    revert Φ HΦ. induction l as [|x l IH]=> Φ HΦ; [by auto using big_sepL_nil'|].
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    rewrite big_sepL_cons. rewrite -persistent_and_sep; apply and_intro.
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    - by rewrite (forall_elim 0) (forall_elim x) pure_True // True_impl.
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    - rewrite -IH. apply forall_intro=> k; by rewrite (forall_elim (S k)).
  Qed.

  Lemma big_sepL_impl Φ Ψ l :
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    ([ list] kx  l, Φ k x) -
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     ( k x, l !! k = Some x  Φ k x - Ψ k x) -
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    [ list] kx  l, Ψ k x.
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  Proof.
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    apply wand_intro_l. revert Φ Ψ. induction l as [|x l IH]=> Φ Ψ /=.
    { by rewrite sep_elim_r. }
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    rewrite intuitionistically_sep_dup -assoc [( _  _)%I]comm -!assoc assoc.
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    apply sep_mono.
    - rewrite (forall_elim 0) (forall_elim x) pure_True // True_impl.
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      by rewrite intuitionistically_elim wand_elim_l.
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    - rewrite comm -(IH (Φ  S) (Ψ  S)) /=.
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      apply sep_mono_l, affinely_mono, persistently_mono.
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      apply forall_intro=> k. by rewrite (forall_elim (S k)).
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  Qed.

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  Lemma big_sepL_delete Φ l i x :
    l !! i = Some x 
    ([ list] ky  l, Φ k y)
     Φ i x  [ list] ky  l, if decide (k = i) then emp else Φ k y.
  Proof.
    intros. rewrite -(take_drop_middle l i x) // !big_sepL_app /= Nat.add_0_r.
    rewrite take_length_le; last eauto using lookup_lt_Some, Nat.lt_le_incl.
    rewrite decide_True // left_id.
    rewrite assoc -!(comm _ (Φ _ _)) -assoc. do 2 f_equiv.
    - apply big_sepL_proper=> k y Hk. apply lookup_lt_Some in Hk.
      rewrite take_length in Hk. by rewrite decide_False; last lia.
    - apply big_sepL_proper=> k y _. by rewrite decide_False; last lia.
  Qed.

  Lemma big_sepL_delete' `{!BiAffine PROP} Φ l i x :
    l !! i = Some x 
    ([ list] ky  l, Φ k y)  Φ i x  [ list] ky  l,  k  i   Φ k y.
  Proof.
    intros. rewrite big_sepL_delete //. (do 2 f_equiv)=> k y.
    rewrite -decide_emp. by repeat case_decide.
  Qed.

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  Global Instance big_sepL_nil_persistent Φ :
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    Persistent ([ list] kx  [], Φ k x).
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  Proof. simpl; apply _. Qed.
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  Global Instance big_sepL_persistent Φ l :
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    ( k x, Persistent (Φ k x))  Persistent ([ list] kx  l, Φ k x).
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  Proof. revert Φ. induction l as [|x l IH]=> Φ ? /=; apply _. Qed.
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  Global Instance big_sepL_persistent_id Ps :
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    TCForall Persistent Ps  Persistent ([] Ps).
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  Proof. induction 1; simpl; apply _. Qed.
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  Global Instance big_sepL_nil_affine Φ :
    Affine ([ list] kx  [], Φ k x).
  Proof. simpl; apply _. Qed.
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  Global Instance big_sepL_affine Φ l :
    ( k x, Affine (Φ k x))  Affine ([ list] kx  l, Φ k x).
  Proof. revert Φ. induction l as [|x l IH]=> Φ ? /=; apply _. Qed.
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  Global Instance big_sepL_affine_id Ps : TCForall Affine Ps  Affine ([] Ps).
  Proof. induction 1; simpl; apply _. Qed.
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End sep_list.
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Section sep_list_more.
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  Context {A : Type}.
  Implicit Types l : list A.
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  Implicit Types Φ Ψ : nat  A  PROP.
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  (* Some lemmas depend on the generalized versions of the above ones. *)

  Lemma big_sepL_zip_with {B C} Φ f (l1 : list B) (l2 : list C) :
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    ([ list] kx  zip_with f l1 l2, Φ k x)
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     ([ list] kx  l1, if l2 !! k is Some y then Φ k (f x y) else emp).
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  Proof.
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    revert Φ l2; induction l1 as [|x l1 IH]=> Φ [|y l2] //=.
    - by rewrite big_sepL_emp left_id.
    - by rewrite IH.
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  Qed.
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End sep_list_more.

Lemma big_sepL2_alt {A B} (Φ : nat  A  B  PROP) l1 l2 :
  ([ list] ky1;y2  l1; l2, Φ k y1 y2)
    length l1 = length l2   [ list] k  y  zip l1 l2, Φ k (y.1) (y.2).
Proof.
  apply (anti_symm _).
  - apply and_intro.
    + revert Φ l2. induction l1 as [|x1 l1 IH]=> Φ -[|x2 l2] /=;
        auto using pure_intro, False_elim.
      rewrite IH sep_elim_r. apply pure_mono; auto.
    + revert Φ l2. induction l1 as [|x1 l1 IH]=> Φ -[|x2 l2] /=;
        auto using pure_intro, False_elim.
      by rewrite IH.
  - apply pure_elim_l=> /Forall2_same_length Hl. revert Φ.
    induction Hl as [|x1 l1 x2 l2 _ _ IH]=> Φ //=. by rewrite -IH.
Qed.

(** ** Big ops over two lists *)
Section sep_list2.
  Context {A B : Type}.
  Implicit Types Φ Ψ : nat  A  B  PROP.

  Lemma big_sepL2_nil Φ : ([ list] ky1;y2  []; [], Φ k y1 y2)  emp.
  Proof. done. Qed.
  Lemma big_sepL2_nil' `{BiAffine PROP} P Φ : P  [ list] ky1;y2  [];[], Φ k y1 y2.
  Proof. apply (affine _). Qed.

  Lemma big_sepL2_cons Φ x1 x2 l1 l2 :
    ([ list] ky1;y2  x1 :: l1; x2 :: l2, Φ k y1 y2)
     Φ 0 x1 x2  [ list] ky1;y2  l1;l2, Φ (S k) y1 y2.
  Proof. done. Qed.
  Lemma big_sepL2_cons_inv_l Φ x1 l1 l2 :
    ([ list] ky1;y2  x1 :: l1; l2, Φ k y1 y2) -
     x2 l2',  l2 = x2 :: l2'  
              Φ 0 x1 x2  [ list] ky1;y2  l1;l2', Φ (S k) y1 y2.
  Proof.
    destruct l2 as [|x2 l2]; simpl; auto using False_elim.
    by rewrite -(exist_intro x2) -(exist_intro l2) pure_True // left_id.
  Qed.
  Lemma big_sepL2_cons_inv_r Φ x2 l1 l2 :
    ([ list] ky1;y2  l1; x2 :: l2, Φ k y1 y2) -
     x1 l1',  l1 = x1 :: l1'  
              Φ 0 x1 x2  [ list] ky1;y2  l1';l2, Φ (S k) y1 y2.
  Proof.
    destruct l1 as [|x1 l1]; simpl; auto using False_elim.
    by rewrite -(exist_intro x1) -(exist_intro l1) pure_True // left_id.
  Qed.

  Lemma big_sepL2_singleton Φ x1 x2 :
    ([ list] ky1;y2  [x1];[x2], Φ k y1 y2)  Φ 0 x1 x2.
  Proof. by rewrite /= right_id. Qed.

  Lemma big_sepL2_length Φ l1 l2 :
    ([ list] ky1;y2  l1; l2, Φ k y1 y2) -  length l1 = length l2 .
  Proof. by rewrite big_sepL2_alt and_elim_l. Qed.

  Lemma big_sepL2_app Φ l1 l2 l1' l2' :
    ([ list] ky1;y2  l1; l1', Φ k y1 y2) -
    ([ list] ky1;y2  l2; l2', Φ (length l1 + k) y1 y2) -
    ([ list] ky1;y2  l1 ++ l2; l1' ++ l2', Φ k y1 y2).
  Proof.
    apply wand_intro_r. revert Φ l1'. induction l1 as [|x1 l1 IH]=> Φ -[|x1' l1'] /=.
    - by rewrite left_id.
    - rewrite left_absorb. apply False_elim.
    - rewrite left_absorb. apply False_elim.
    - by rewrite -assoc IH.
  Qed.
  Lemma big_sepL2_app_inv_l Φ l1' l1'' l2 :
    ([ list] ky1;y2  l1' ++ l1''; l2, Φ k y1 y2) -
     l2' l2'',  l2 = l2' ++ l2''  
                ([ list] ky1;y2  l1';l2', Φ k y1 y2) 
                ([ list] ky1;y2  l1'';l2'', Φ (length l1' + k) y1 y2).
  Proof.
    rewrite -(exist_intro (take (length l1') l2))
      -(exist_intro (drop (length l1') l2)) take_drop pure_True // left_id.
    revert Φ l2. induction l1' as [|x1 l1' IH]=> Φ -[|x2 l2] /=;
       [by rewrite left_id|by rewrite left_id|apply False_elim|].
    by rewrite IH -assoc.
  Qed.
  Lemma big_sepL2_app_inv_r Φ l1 l2' l2'' :
    ([ list] ky1;y2  l1; l2' ++ l2'', Φ k y1 y2) -
     l1' l1'',  l1 = l1' ++ l1''  
                ([ list] ky1;y2  l1';l2', Φ k y1 y2) 
                ([ list] ky1;y2  l1'';l2'', Φ (length l2' + k) y1 y2).
  Proof.
    rewrite -(exist_intro (take (length l2') l1))
      -(exist_intro (drop (length l2') l1)) take_drop pure_True // left_id.
    revert Φ l1. induction l2' as [|x2 l2' IH]=> Φ -[|x1 l1] /=;
       [by rewrite left_id|by rewrite left_id|apply False_elim|].
    by rewrite IH -assoc.
  Qed.

  Lemma big_sepL2_mono Φ Ψ l1 l2 :
    ( k y1 y2, l1 !! k = Some y1  l2 !! k = Some y2  Φ k y1 y2  Ψ k y1 y2) 
    ([ list] k  y1;y2  l1;l2, Φ k y1 y2)  [ list] k  y1;y2  l1;l2, Ψ k y1 y2.
  Proof.
    intros H. rewrite !big_sepL2_alt. f_equiv. apply big_sepL_mono=> k [y1 y2].
    rewrite lookup_zip_with=> ?; simplify_option_eq; auto.
  Qed.
  Lemma big_sepL2_proper Φ Ψ l1 l2 :
    ( k y1 y2, l1 !! k = Some y1  l2 !! k = Some y2  Φ k y1 y2  Ψ k y1 y2) 
    ([ list] k  y1;y2  l1;l2, Φ k y1 y2)  [ list] k  y1;y2  l1;l2, Ψ k y1 y2.
  Proof.
    intros; apply (anti_symm _);
      apply big_sepL2_mono; auto using equiv_entails, equiv_entails_sym.
  Qed.

  Global Instance big_sepL2_ne n :
    Proper (pointwise_relation _ (pointwise_relation _ (pointwise_relation _ (dist n)))
      ==> (=) ==> (=) ==> (dist n))
           (big_sepL2 (PROP:=PROP) (A:=A) (B:=B)).
  Proof.
    intros Φ1 Φ2 HΦ x1 ? <- x2 ? <-. rewrite !big_sepL2_alt. f_equiv.
    f_equiv=> k [y1 y2]. apply HΦ.
  Qed.
  Global Instance big_sepL2_mono' :
    Proper (pointwise_relation _ (pointwise_relation _ (pointwise_relation _ ()))
      ==> (=) ==> (=) ==> ())
           (big_sepL2 (PROP:=PROP) (A:=A) (B:=B)).
  Proof. intros f g Hf l1 ? <- l2 ? <-. apply big_sepL2_mono; intros; apply Hf. Qed.
  Global Instance big_sepL2_proper' :
    Proper (pointwise_relation _ (pointwise_relation _ (pointwise_relation _ ()))
      ==> (=) ==> (=) ==> ())
           (big_sepL2 (PROP:=PROP) (A:=A) (B:=B)).
  Proof. intros f g Hf l1 ? <- l2 ? <-. apply big_sepL2_proper; intros; apply Hf. Qed.

  Lemma big_sepL2_lookup_acc Φ l1 l2 i x1 x2 :
    l1 !! i = Some x1  l2 !! i = Some x2 
    ([ list] ky1;y2  l1;l2, Φ k y1 y2) 
    Φ i x1 x2  (Φ i x1 x2 - ([ list] ky1;y2  l1;l2, Φ k y1 y2)).
  Proof.
    intros Hl1 Hl2. rewrite big_sepL2_alt. apply pure_elim_l=> Hl.
    rewrite {1}big_sepL_lookup_acc; last by rewrite lookup_zip_with; simplify_option_eq.
    by rewrite pure_True // left_id.
  Qed.

  Lemma big_sepL2_lookup Φ l1 l2 i x1 x2 `{!Absorbing (Φ i x1 x2)} :
    l1 !! i = Some x1  l2 !! i = Some x2 
    ([ list] ky1;y2  l1;l2, Φ k y1 y2)  Φ i x1 x2.
  Proof. intros. rewrite big_sepL2_lookup_acc //. by rewrite sep_elim_l. Qed.

  Lemma big_sepL2_fmap_l {A'} (f : A  A') (Φ : nat  A'  B  PROP) l1 l2 :
    ([ list] ky1;y2  f <$> l1; l2, Φ k y1 y2)
     ([ list] ky1;y2  l1;l2, Φ k (f y1) y2).
  Proof.
    rewrite !big_sepL2_alt fmap_length zip_with_fmap_l zip_with_zip big_sepL_fmap.
    by f_equiv; f_equiv=> k [??].
  Qed.
  Lemma big_sepL2_fmap_r {B'} (g : B  B') (Φ : nat  A  B'  PROP) l1 l2 :
    ([ list] ky1;y2  l1; g <$> l2, Φ k y1 y2)
     ([ list] ky1;y2  l1;l2, Φ k y1 (g y2)).
  Proof.
    rewrite !big_sepL2_alt fmap_length zip_with_fmap_r zip_with_zip big_sepL_fmap.
    by f_equiv; f_equiv=> k [??].
  Qed.

  Lemma big_sepL2_sepL2 Φ Ψ l1 l2 :
    ([ list] ky1;y2  l1;l2, Φ k y1 y2  Ψ k y1 y2)
     ([ list] ky1;y2  l1;l2, Φ k y1 y2)  ([ list] ky1;y2  l1;l2, Ψ k y1 y2).
  Proof.
    rewrite !big_sepL2_alt big_sepL_sepL !persistent_and_affinely_sep_l.
    rewrite -assoc (assoc _ _ (<affine> _)%I). rewrite -(comm bi_sep (<affine> _)%I).
    rewrite -assoc (assoc _ _ (<affine> _)%I) -!persistent_and_affinely_sep_l.
    by rewrite affinely_and_r persistent_and_affinely_sep_l idemp.
  Qed.

  Lemma big_sepL2_and Φ Ψ l1 l2 :
    ([ list] ky1;y2  l1;l2, Φ k y1 y2  Ψ k y1 y2)
     ([ list] ky1;y2  l1;l2, Φ k y1 y2)  ([ list] ky1;y2  l1;l2, Ψ k y1 y2).
  Proof. auto using and_intro, big_sepL2_mono, and_elim_l, and_elim_r. Qed.

  Lemma big_sepL2_persistently `{BiAffine PROP} Φ l1 l2 :
    <pers> ([ list] ky1;y2  l1;l2, Φ k y1 y2)
     [ list] ky1;y2  l1;l2, <pers> (Φ k y1 y2).
  Proof.
    by rewrite !big_sepL2_alt persistently_and persistently_pure big_sepL_persistently.
  Qed.

  Lemma big_sepL2_impl Φ Ψ l1 l2 :
    ([ list] ky1;y2  l1;l2, Φ k y1 y2) -
     ( k x1 x2,
      l1 !! k = Some x1  l2 !! k = Some x2  Φ k x1 x2 - Ψ k x1 x2) -
    [ list] ky1;y2  l1;l2, Ψ k y1 y2.
  Proof.
    apply wand_intro_l. revert Φ Ψ l2.
    induction l1 as [|x1 l1 IH]=> Φ Ψ [|x2 l2] /=; [by rewrite sep_elim_r..|].
    rewrite intuitionistically_sep_dup -assoc [( _  _)%I]comm -!assoc assoc.
    apply sep_mono.
    - rewrite (forall_elim 0) (forall_elim x1) (forall_elim x2) !pure_True // !True_impl.
      by rewrite intuitionistically_elim wand_elim_l.
    - rewrite comm -(IH (Φ  S) (Ψ  S)) /=.
      apply sep_mono_l, affinely_mono, persistently_mono.
      apply forall_intro=> k. by rewrite (forall_elim (S k)).
  Qed.

  Global Instance big_sepL2_nil_persistent Φ :
    Persistent ([ list] ky1;y2  []; [], Φ k y1 y2).
  Proof. simpl; apply _. Qed.
  Global Instance big_sepL2_persistent Φ l1 l2 :
    ( k x1 x2, Persistent (Φ k x1 x2)) 
    Persistent ([ list] ky1;y2  l1;l2, Φ k y1 y2).
  Proof. rewrite big_sepL2_alt. apply _. Qed.

  Global Instance big_sepL2_nil_affine Φ :
    Affine ([ list] ky1;y2  []; [], Φ k y1 y2).
  Proof. simpl; apply _. Qed.
  Global Instance big_sepL2_affine Φ l1 l2 :
    ( k x1 x2, Affine (Φ k x1 x2)) 
    Affine ([ list] ky1;y2  l1;l2, Φ k y1 y2).
  Proof. rewrite big_sepL2_alt. apply _. Qed.
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End sep_list2.

Section and_list.
  Context {A : Type}.
  Implicit Types l : list A.
  Implicit Types Φ Ψ : nat  A  PROP.

  Lemma big_andL_nil Φ : ([ list] ky  nil, Φ k y)  True.
  Proof. done. Qed.
  Lemma big_andL_nil' P Φ : P  [ list] ky  nil, Φ k y.
  Proof. by apply pure_intro. Qed.
  Lemma big_andL_cons Φ x l :
    ([ list] ky  x :: l, Φ k y)  Φ 0 x  [ list] ky  l, Φ (S k) y.
  Proof. by rewrite big_opL_cons. Qed.
  Lemma big_andL_singleton Φ x : ([ list] ky  [x], Φ k y)  Φ 0 x.
  Proof. by rewrite big_opL_singleton. Qed.
  Lemma big_andL_app Φ l1 l2 :
    ([ list] ky  l1 ++ l2, Φ k y)
     ([ list] ky  l1, Φ k y)  ([ list] ky  l2, Φ (length l1 + k) y).
  Proof. by rewrite big_opL_app. Qed.

  Lemma big_andL_mono Φ Ψ l :
    ( k y, l !! k = Some y  Φ k y  Ψ k y) 
    ([ list] k  y  l, Φ k y)  [ list] k  y  l, Ψ k y.
  Proof. apply big_opL_forall; apply _. Qed.
  Lemma big_andL_proper Φ Ψ l :
    ( k y, l !! k = Some y  Φ k y  Ψ k y) 
    ([ list] k  y  l, Φ k y)  ([ list] k  y  l, Ψ k y).
  Proof. apply big_opL_proper. Qed.
  Lemma big_andL_submseteq (Φ : A  PROP) l1 l2 :
    l1 + l2  ([ list] y  l2, Φ y)  [ list] y  l1, Φ y.
  Proof.
    intros [l ->]%submseteq_Permutation. by rewrite big_andL_app and_elim_l.
  Qed.

  Global Instance big_andL_mono' :
    Proper (pointwise_relation _ (pointwise_relation _ ()) ==> (=) ==> ())
           (big_opL (@bi_and PROP) (A:=A)).
  Proof. intros f g Hf m ? <-. apply big_opL_forall; apply _ || intros; apply Hf. Qed.
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  Global Instance big_andL_id_mono' :
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    Proper (Forall2 () ==> ()) (big_opL (@bi_and PROP) (λ _ P, P)).
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  Proof. by induction 1 as [|P Q Ps Qs HPQ ? IH]; rewrite /= ?HPQ ?IH. Qed.

  Lemma big_andL_lookup Φ l i x `{!Absorbing (Φ i x)} :
    l !! i = Some x  ([ list] ky  l, Φ k y)  Φ i x.
  Proof.
    intros. rewrite -(take_drop_middle l i x) // big_andL_app /=.
    rewrite Nat.add_0_r take_length_le;
      eauto using lookup_lt_Some, Nat.lt_le_incl, and_elim_l', and_elim_r'.
  Qed.

  Lemma big_andL_elem_of (Φ : A  PROP) l x `{!Absorbing (Φ x)} :
    x  l  ([ list] y  l, Φ y)  Φ x.
  Proof.
    intros [i ?]%elem_of_list_lookup; eauto using (big_andL_lookup (λ _, Φ)).
  Qed.

  Lemma big_andL_fmap {B} (f : A  B) (Φ : nat  B  PROP) l :
    ([ list] ky  f <$> l, Φ k y)  ([ list] ky  l, Φ k (f y)).
  Proof. by rewrite big_opL_fmap. Qed.

  Lemma big_andL_andL Φ Ψ l :
    ([ list] kx  l, Φ k x  Ψ k x)
     ([ list] kx  l, Φ k x)  ([ list] kx  l, Ψ k x).
  Proof. by rewrite big_opL_opL. Qed.

  Lemma big_andL_and Φ Ψ l :
    ([ list] kx  l, Φ k x  Ψ k x)
     ([ list] kx  l, Φ k x)  ([ list] kx  l, Ψ k x).
  Proof. auto using and_intro, big_andL_mono, and_elim_l, and_elim_r. Qed.

  Lemma big_andL_persistently Φ l :
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    <pers> ([ list] kx  l, Φ k x)  [ list] kx  l, <pers> (Φ k x).
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  Proof. apply (big_opL_commute _). Qed.

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  Lemma big_andL_forall `{BiAffine PROP} Φ l :
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    ([ list] kx  l, Φ k x)  ( k x, l !! k = Some x  Φ k x).
  Proof.
    apply (anti_symm _).
    { apply forall_intro=> k; apply forall_intro=> x.
      apply impl_intro_l, pure_elim_l=> ?; by apply: big_andL_lookup. }
    revert Φ. induction l as [|x l IH]=> Φ; [by auto using big_andL_nil'|].
    rewrite big_andL_cons. apply and_intro.
    - by rewrite (forall_elim 0) (forall_elim x) pure_True // True_impl.
    - rewrite -IH. apply forall_intro=> k; by rewrite (forall_elim (S k)).
  Qed.

  Global Instance big_andL_nil_persistent Φ :
    Persistent ([ list] kx  [], Φ k x).
  Proof. simpl; apply _. Qed.
  Global Instance big_andL_persistent Φ l :
    ( k x, Persistent (Φ k x))  Persistent ([ list] kx  l, Φ k x).
  Proof. revert Φ. induction l as [|x l IH]=> Φ ? /=; apply _. Qed.
End and_list.
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(** ** Big ops over finite maps *)
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Section gmap.
  Context `{Countable K} {A : Type}.
  Implicit Types m : gmap K A.
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  Implicit Types Φ Ψ : K  A  PROP.
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  Lemma big_sepM_mono Φ Ψ m :
    ( k x, m !! k = Some x  Φ k x  Ψ k x) 
    ([ map] k  x  m, Φ k x)  [ map] k  x  m, Ψ k x.
  Proof. apply big_opM_forall; apply _ || auto. Qed.
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  Lemma big_sepM_proper Φ Ψ m :
    ( k x, m !! k = Some x  Φ k x  Ψ k x) 
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    ([ map] k  x  m, Φ k x)  ([ map] k  x  m, Ψ k x).
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  Proof. apply big_opM_proper. Qed.
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  Lemma big_sepM_subseteq `{BiAffine PROP} Φ m1 m2 :
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    m2  m1  ([ map] k  x  m1, Φ k x)  [ map] k  x  m2, Φ k x.
  Proof. intros. by apply big_sepL_submseteq, map_to_list_submseteq. Qed.
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  Global Instance big_sepM_mono' :
    Proper (pointwise_relation _ (pointwise_relation _ ()) ==> (=) ==> ())
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           (big_opM (@bi_sep PROP) (K:=K) (A:=A)).
  Proof. intros f g Hf m ? <-. apply big_sepM_mono=> ???; apply Hf. Qed.
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  Lemma big_sepM_empty Φ : ([ map] kx  , Φ k x)  emp.
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  Proof. by rewrite big_opM_empty. Qed.
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  Lemma big_sepM_empty' `{BiAffine PROP} P Φ : P  [ map] kx  , Φ k x.
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  Proof. rewrite big_sepM_empty. apply: affine. Qed.
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  Lemma big_sepM_insert Φ m i x :
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    m !! i = None 
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    ([ map] ky  <[i:=x]> m, Φ k y)  Φ i x  [ map] ky  m, Φ k y.
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  Proof. apply big_opM_insert. Qed.
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  Lemma big_sepM_delete Φ m i x :
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    m !! i = Some x 
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    ([ map] ky  m, Φ k y)  Φ i x  [ map] ky  delete i m, Φ k y.
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  Proof. apply big_opM_delete. Qed.
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  Lemma big_sepM_lookup_acc Φ m i x :
    m !! i = Some x 
    ([ map] ky  m, Φ k y)  Φ i x  (Φ i x - ([ map] ky  m, Φ k y)).
  Proof.
    intros. rewrite big_sepM_delete //. by apply sep_mono_r, wand_intro_l.
  Qed.

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  Lemma big_sepM_lookup Φ m i x `{!Absorbing (Φ i x)} :
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    m !! i = Some x  ([ map] ky  m, Φ k y)  Φ i x.
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  Proof. intros. rewrite big_sepM_lookup_acc //. by rewrite sep_elim_l. Qed.
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  Lemma big_sepM_lookup_dom (Φ : K  PROP) m i `{!Absorbing (Φ i)} :
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    is_Some (m !! i)  ([ map] k_  m, Φ k)  Φ i.
  Proof. intros [x ?]. by eapply (big_sepM_lookup (λ i x, Φ i)). Qed.
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  Lemma big_sepM_singleton Φ i x : ([ map] ky  {[i:=x]}, Φ k y)  Φ i x.
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  Proof. by rewrite big_opM_singleton. Qed.
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  Lemma big_sepM_fmap {B} (f : A  B) (Φ : K  B  PROP) m :
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    ([ map] ky  f <$> m, Φ k y)  ([ map] ky  m, Φ k (f y)).
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  Proof. by rewrite big_opM_fmap. Qed.
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  Lemma big_sepM_insert_override Φ m i x x' :
    m !! i = Some x  (Φ i x  Φ i x') 
    ([ map] ky  <[i:=x']> m, Φ k y)  ([ map] ky  m, Φ k y).
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  Proof. apply big_opM_insert_override. Qed.
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  Lemma big_sepM_insert_override_1 Φ m i x x' :
    m !! i = Some x 
    ([ map] ky  <[i:=x']> m, Φ k y) 
      (Φ i x' - Φ i x) - ([ map] ky  m, Φ k y).
  Proof.
    intros ?. apply wand_intro_l.
    rewrite -insert_delete big_sepM_insert ?lookup_delete //.
    by rewrite assoc wand_elim_l -big_sepM_delete.
  Qed.

  Lemma big_sepM_insert_override_2 Φ m i x x' :
    m !! i = Some x 
    ([ map] ky  m, Φ k y) 
      (Φ i x - Φ i x') - ([ map] ky  <[i:=x']> m, Φ k y).
  Proof.
    intros ?. apply wand_intro_l.
    rewrite {1}big_sepM_delete //; rewrite assoc wand_elim_l.
    rewrite -insert_delete big_sepM_insert ?lookup_delete //.
  Qed.

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  Lemma big_sepM_fn_insert {B} (Ψ : K  A  B  PROP) (f : K  B) m i x b :
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    m !! i = None 
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       ([ map] ky  <[i:=x]> m, Ψ k y (<[i:=b]> f k))
     (Ψ i x b  [ map] ky  m, Ψ k y (f k)).
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  Proof. apply big_opM_fn_insert. Qed.
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  Lemma big_sepM_fn_insert' (Φ : K  PROP) m i x P :
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    m !! i = None 
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    ([ map] ky  <[i:=x]> m, <[i:=P]> Φ k)  (P  [ map] ky  m, Φ k).
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  Proof. apply big_opM_fn_insert'. Qed.
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  Lemma big_sepM_sepM Φ Ψ m :
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    ([ map] kx  m, Φ k x  Ψ k x)
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     ([ map] kx  m, Φ k x)  ([ map] kx  m, Ψ k x).
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  Proof. apply big_opM_opM. Qed.
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  Lemma big_sepM_and Φ Ψ m :
    ([ map] kx  m, Φ k x  Ψ k x)
     ([ map] kx  m, Φ k x)  ([ map] kx  m, Ψ k x).
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  Proof. auto using and_intro, big_sepM_mono, and_elim_l, and_elim_r. Qed.
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  Lemma big_sepM_persistently `{BiAffine PROP} Φ m :
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    (<pers> ([ map] kx  m, Φ k x))  ([ map] kx  m, <pers> (Φ k x)).
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  Proof. apply (big_opM_commute _). Qed.
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  Lemma big_sepM_forall `{BiAffine PROP} Φ m :
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    ( k x, Persistent (Φ k x)) 
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    ([ map] kx  m, Φ k x)  ( k x, m !! k = Some x  Φ k x).
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  Proof.
    intros. apply (anti_symm _).
    { apply forall_intro=> k; apply forall_intro=> x.
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      apply impl_intro_l, pure_elim_l=> ?; by apply: big_sepM_lookup. }
    induction m as [|i x m ? IH] using map_ind; auto using big_sepM_empty'.
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    rewrite big_sepM_insert // -persistent_and_sep. apply and_intro.
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    - rewrite (forall_elim i) (forall_elim x) lookup_insert.
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      by rewrite pure_True // True_impl.
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    - rewrite -IH. apply forall_mono=> k; apply forall_mono=> y.
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      apply impl_intro_l, pure_elim_l=> ?.
      rewrite lookup_insert_ne; last by intros ?; simplify_map_eq.
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      by rewrite pure_True // True_impl.
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  Qed.

  Lemma big_sepM_impl Φ Ψ m :
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    ([ map] kx  m, Φ k x) -
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     ( k x, m !! k = Some x  Φ k x - Ψ k x) -
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    [ map] kx  m, Ψ k x.
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  Proof.
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    apply wand_intro_l. induction m as [|i x m ? IH] using map_ind.
    { by rewrite sep_elim_r. }
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    rewrite !big_sepM_insert // intuitionistically_sep_dup.
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    rewrite -assoc [( _  _)%I]comm -!assoc assoc. apply sep_mono.
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    - rewrite (forall_elim i) (forall_elim x) pure_True ?lookup_insert //.
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      by rewrite True_impl intuitionistically_elim wand_elim_l.
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    - rewrite comm -IH /=.
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      apply sep_mono_l, affinely_mono, persistently_mono, forall_mono=> k.
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      apply forall_mono=> y. apply impl_intro_l, pure_elim_l=> ?.
      rewrite lookup_insert_ne; last by intros ?; simplify_map_eq.
      by rewrite pure_True // True_impl.
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  Qed.
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  Global Instance big_sepM_empty_persistent Φ :
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    Persistent ([ map] kx  , Φ k x).
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  Proof. rewrite /big_opM map_to_list_empty. apply _. Qed.
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  Global Instance big_sepM_persistent Φ m :
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    ( k x, Persistent (Φ k x))  Persistent ([ map] kx  m, Φ k x).
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  Proof. intros. apply big_sepL_persistent=> _ [??]; apply _. Qed.
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  Global Instance big_sepM_empty_affine Φ :
    Affine ([ map] kx  , Φ k x).
  Proof. rewrite /big_opM map_to_list_empty. apply _. Qed.
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  Global Instance big_sepM_affine Φ m :
    ( k x, Affine (Φ k x))  Affine ([ map] kx  m, Φ k x).
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  Proof. intros. apply big_sepL_affine=> _ [??]; apply _. Qed.
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End gmap.

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(** ** Big ops over finite sets *)
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Section gset.
  Context `{Countable A}.
  Implicit Types X : gset A.
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  Implicit Types Φ : A  PROP.
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  Lemma big_sepS_mono Φ Ψ X :
    ( x, x  X  Φ x  Ψ x) 
    ([ set] x  X, Φ x)  [ set] x  X, Ψ x.
  Proof. intros. apply big_opS_forall; apply _ || auto. Qed.
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  Lemma big_sepS_proper Φ Ψ X :
    ( x, x  X  Φ x  Ψ x) 
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    ([ set] x  X, Φ x)  ([ set] x  X, Ψ x).
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  Proof. apply big_opS_proper. Qed.
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  Lemma big_sepS_subseteq `{BiAffine PROP} Φ X Y :
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    Y  X  ([ set] x  X, Φ x)  [ set] x  Y, Φ x.
  Proof. intros. by apply big_sepL_submseteq, elements_submseteq. Qed.
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  Global Instance big_sepS_mono' :
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     Proper (pointwise_relation _ () ==> (=) ==> ()) (big_opS (@bi_sep PROP) (A:=A)).
  Proof. intros f g Hf m ? <-. by apply big_sepS_mono. Qed.
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  Lemma big_sepS_empty Φ : ([ set] x  , Φ x)  emp.
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  Proof. by rewrite big_opS_empty. Qed.
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  Lemma big_sepS_empty' `{!BiAffine PROP} P Φ : P  [ set] x  , Φ x.
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  Proof. rewrite big_sepS_empty. apply: affine. Qed.
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  Lemma big_sepS_insert Φ X x :
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    x  X  ([ set] y  {[ x ]}  X, Φ y)  (Φ x  [ set] y  X, Φ y).
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  Proof. apply big_opS_insert. Qed.
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  Lemma big_sepS_fn_insert {B} (Ψ : A  B  PROP) f X x b :
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    x  X 
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       ([ set] y  {[ x ]}  X, Ψ y (<[x:=b]> f y))
     (Ψ x b  [ set] y  X, Ψ y (f y)).
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  Proof. apply big_opS_fn_insert. Qed.
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  Lemma big_sepS_fn_insert' Φ X x P :
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    x  X  ([ set] y  {[ x ]}  X, <[x:=P]> Φ y)  (P  [ set] y  X, Φ y).
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  Proof. apply big_opS_fn_insert'. Qed.
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  Lemma big_sepS_union Φ X Y :
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    X ## Y 
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    ([ set] y  X  Y, Φ y)  ([ set] y  X, Φ y)  ([ set] y  Y, Φ y).
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  Proof. apply big_opS_union. Qed.
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  Lemma big_sepS_delete Φ X x :
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    x  X  ([ set] y  X, Φ y)  Φ x  [ set] y  X  {[ x ]}, Φ y.
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  Proof. apply big_opS_delete. Qed.
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  Lemma big_sepS_elem_of Φ X x `{!Absorbing (Φ x)} :
    x  X  ([ set] y  X, Φ y)  Φ x.
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  Proof. intros. rewrite big_sepS_delete //. by rewrite sep_elim_l. Qed.
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  Lemma big_sepS_elem_of_acc Φ X x :
    x  X 
    ([ set] y  X, Φ y)  Φ x  (Φ x - ([ set] y  X, Φ y)).
  Proof.
    intros. rewrite big_sepS_delete //. by apply sep_mono_r, wand_intro_l.
  Qed.

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  Lemma big_sepS_singleton Φ x : ([ set] y  {[ x ]}, Φ y)  Φ x.
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  Proof. apply big_opS_singleton. Qed.
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  Lemma big_sepS_filter' (P : A  Prop) `{ x, Decision (P x)} Φ X :
    ([ set] y  filter P X, Φ y)
     ([ set] y  X, if decide (P y) then Φ y else emp).
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  Proof.
    induction X as [|x X ? IH] using collection_ind_L.
    { by rewrite filter_empty_L !big_sepS_empty. }
    destruct (decide (P x)).
    - rewrite filter_union_L filter_singleton_L //.
      rewrite !big_sepS_insert //; last set_solver.
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      by rewrite decide_True // IH.
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    - rewrite filter_union_L filter_singleton_not_L // left_id_L.
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      by rewrite !big_sepS_insert // decide_False // IH left_id.
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  Qed.

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  Lemma big_sepS_filter_acc' (P : A  Prop) `{ y, Decision (P y)} Φ X Y :
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    ( y, y  Y  P y  y  X) 
    ([ set] y  X, Φ y) -
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      ([ set] y  Y, if decide (P y) then Φ y else emp) 
      (([ set] y  Y, if decide (P y) then Φ y else emp) - [ set] y  X, Φ y).
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  Proof.
    intros ?. destruct (proj1 (subseteq_disjoint_union_L (filter P Y) X))
      as (Z&->&?); first set_solver.
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    rewrite big_sepS_union // big_sepS_filter'.
    by apply sep_mono_r, wand_intro_l.
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  Qed.

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  Lemma big_sepS_filter `{BiAffine PROP}
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      (P : A  Prop) `{ x, Decision (P x)} Φ X :
    ([ set] y  filter P X, Φ y)  ([ set] y  X, P y  Φ y).
  Proof. setoid_rewrite <-decide_emp. apply big_sepS_filter'. Qed.

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  Lemma big_sepS_filter_acc `{BiAffine PROP}