Library iris.algebra.cmra

From iris.algebra Require Export cofe step.

Class PCore (A : Type) := pcore : A option A.
Instance: Params (@pcore) 2.

Class Op (A : Type) := op : A A A.
Instance: Params (@op) 2.
Infix "⋅" := op (at level 50, left associativity) : C_scope.
Notation "(⋅)" := op (only parsing) : C_scope.

Definition included `{Equiv A, Op A} (x y : A) := z, y x z.
Infix "≼" := included (at level 70) : C_scope.
Notation "(≼)" := included (only parsing) : C_scope.
Hint Extern 0 (_ _) ⇒ reflexivity.
Instance: Params (@included) 3.

Class ValidN (A : Type) := validN : nat A Prop.
Instance: Params (@validN) 3.
Notation "✓{ n } x" := (validN n x)
  (at level 20, n at next level, format "✓{ n } x").

Class Valid (A : Type) := valid : A Prop.
Instance: Params (@valid) 2.
Notation "✓ x" := (valid x) (at level 20) : C_scope.

Definition includedN `{Dist A, Op A} (n : nat) (x y : A) := z, y ≡{n}≡ x z.
Notation "x ≼{ n } y" := (includedN n x y)
  (at level 70, n at next level, format "x ≼{ n } y") : C_scope.
Instance: Params (@includedN) 4.
Hint Extern 0 (_ ≼{_} _) ⇒ reflexivity.

Record CMRAMixin A
    `{Dist A, Equiv A, PCore A, Op A, Valid A, ValidN A, StepN A} := {
  
  mixin_cmra_op_ne n (x : A) : Proper (dist n ==> dist n) (op x);
  mixin_cmra_pcore_ne n x y cx :
    x ≡{n}≡ y pcore x = Some cx cy, pcore y = Some cy cx ≡{n}≡ cy;
  mixin_cmra_validN_ne n : Proper (dist n ==> impl) (validN n);
  
  mixin_cmra_valid_validN x : x n, ✓{n} x;
  mixin_cmra_validN_S n x : ✓{S n} x ✓{n} x;
  
  mixin_cmra_assoc : Assoc (≡) (⋅);
  mixin_cmra_comm : Comm (≡) (⋅);
  mixin_cmra_pcore_l x cx : pcore x = Some cx cx x x;
  mixin_cmra_pcore_idemp x cx : pcore x = Some cx pcore cx Some cx;
  mixin_cmra_pcore_mono x y cx :
    x y pcore x = Some cx cy, pcore y = Some cy cx cy;
  mixin_cmra_pcore_distrib n x y cx cy :
    ✓{n} (x y)
    pcore x = Some cx
    pcore y = Some cy
     cxy, pcore (cx cy) = Some cxy cxy ≡{n}≡ cx cy ;
  mixin_cmra_validN_op_l n x y : ✓{n} (x y) ✓{n} x;
  mixin_cmra_extend n x y1 y2 :
    ✓{n} x x ≡{n}≡ y1 y2
    { z | x z.1 z.2 z.1 ≡{n}≡ y1 z.2 ≡{n}≡ y2 };
  mixin_cmra_stepN_ne n : Proper (dist n ==> dist n ==> impl) (stepN n);
  mixin_cmra_stepN_S n x y: x _(S n) y x _(n) y
}.

Bundeled version
Structure cmraT := CMRAT' {
  cmra_car :> Type;
  cmra_equiv : Equiv cmra_car;
  cmra_dist : Dist cmra_car;
  cmra_compl : Compl cmra_car;
  cmra_pcore : PCore cmra_car;
  cmra_op : Op cmra_car;
  cmra_valid : Valid cmra_car;
  cmra_validN : ValidN cmra_car;
  cmra_stepN : StepN cmra_car;
  cmra_cofe_mixin : CofeMixin cmra_car;
  cmra_mixin : CMRAMixin cmra_car;
  _ : Type
}.
Arguments CMRAT' _ {_ _ _ _ _ _ _ _} _ _ _.
Notation CMRAT A m m' := (CMRAT' A m m' A).
Arguments cmra_car : simpl never.
Arguments cmra_equiv : simpl never.
Arguments cmra_dist : simpl never.
Arguments cmra_compl : simpl never.
Arguments cmra_pcore : simpl never.
Arguments cmra_op : simpl never.
Arguments cmra_valid : simpl never.
Arguments cmra_validN : simpl never.
Arguments cmra_stepN : simpl never.
Arguments cmra_cofe_mixin : simpl never.
Arguments cmra_mixin : simpl never.
Add Printing Constructor cmraT.
Hint Extern 0 (PCore _) ⇒ eapply (@cmra_pcore _) : typeclass_instances.
Hint Extern 0 (Op _) ⇒ eapply (@cmra_op _) : typeclass_instances.
Hint Extern 0 (Valid _) ⇒ eapply (@cmra_valid _) : typeclass_instances.
Hint Extern 0 (ValidN _) ⇒ eapply (@cmra_validN _) : typeclass_instances.
Hint Extern 0 (StepN _) ⇒ eapply (@cmra_stepN _) : typeclass_instances.
Coercion cmra_cofeC (A : cmraT) : cofeT := CofeT A (cmra_cofe_mixin A).
Canonical Structure cmra_cofeC.

Lifting properties from the mixin
Section cmra_mixin.
  Context {A : cmraT}.
  Implicit Types x y : A.
  Global Instance cmra_op_ne n (x : A) : Proper (dist n ==> dist n) (op x).
  Proof. apply (mixin_cmra_op_ne _ (cmra_mixin A)). Qed.
  Lemma cmra_pcore_ne n x y cx :
    x ≡{n}≡ y pcore x = Some cx cy, pcore y = Some cy cx ≡{n}≡ cy.
  Proof. apply (mixin_cmra_pcore_ne _ (cmra_mixin A)). Qed.
  Global Instance cmra_validN_ne n : Proper (dist n ==> impl) (@validN A _ n).
  Proof. apply (mixin_cmra_validN_ne _ (cmra_mixin A)). Qed.
  Lemma cmra_valid_validN x : x n, ✓{n} x.
  Proof. apply (mixin_cmra_valid_validN _ (cmra_mixin A)). Qed.
  Lemma cmra_validN_S n x : ✓{S n} x ✓{n} x.
  Proof. apply (mixin_cmra_validN_S _ (cmra_mixin A)). Qed.
  Global Instance cmra_assoc : Assoc (≡) (@op A _).
  Proof. apply (mixin_cmra_assoc _ (cmra_mixin A)). Qed.
  Global Instance cmra_comm : Comm (≡) (@op A _).
  Proof. apply (mixin_cmra_comm _ (cmra_mixin A)). Qed.
  Lemma cmra_pcore_l x cx : pcore x = Some cx cx x x.
  Proof. apply (mixin_cmra_pcore_l _ (cmra_mixin A)). Qed.
  Lemma cmra_pcore_idemp x cx : pcore x = Some cx pcore cx Some cx.
  Proof. apply (mixin_cmra_pcore_idemp _ (cmra_mixin A)). Qed.
  Lemma cmra_pcore_mono x y cx :
    x y pcore x = Some cx cy, pcore y = Some cy cx cy.
  Proof. apply (mixin_cmra_pcore_mono _ (cmra_mixin A)). Qed.
  Lemma cmra_pcore_distrib n x y cx cy :
    ✓{n} (x y)
    pcore x = Some cx
    pcore y = Some cy
     cxy, pcore (cx cy) = Some cxy cxy ≡{n}≡ (cx cy).
  Proof. apply (mixin_cmra_pcore_distrib _ (cmra_mixin A)). Qed.
  Lemma cmra_validN_op_l n x y : ✓{n} (x y) ✓{n} x.
  Proof. apply (mixin_cmra_validN_op_l _ (cmra_mixin A)). Qed.
  Lemma cmra_extend n x y1 y2 :
    ✓{n} x x ≡{n}≡ y1 y2
    { z | x z.1 z.2 z.1 ≡{n}≡ y1 z.2 ≡{n}≡ y2 }.
  Proof. apply (mixin_cmra_extend _ (cmra_mixin A)). Qed.
  Global Instance cmra_stepN_ne n: Proper (dist n ==> dist n ==> impl) (@stepN A _ n).
  Proof. apply (mixin_cmra_stepN_ne _ (cmra_mixin A)). Qed.
  Lemma cmra_stepN_S n x y: x _(S n) y x _(n) y.
  Proof. apply (mixin_cmra_stepN_S _ (cmra_mixin A)). Qed.
  Global Instance cmra_ustep: uStep A.
  Proof.
    econstructor.
    × eapply cmra_stepN_ne.
    × eapply cmra_stepN_S.
  Qed.
End cmra_mixin.

Definition opM {A : cmraT} (x : A) (my : option A) :=
  match my with Some yx y | Nonex end.
Infix "⋅?" := opM (at level 50, left associativity) : C_scope.

Persistent elements

Class Persistent {A : cmraT} (x : A) := persistent : pcore x Some x.
Arguments persistent {_} _ {_}.

Exclusive elements (i.e., elements that cannot have a frame).

Class Exclusive {A : cmraT} (x : A) := exclusive0_l y : ✓{0} (x y) False.
Arguments exclusive0_l {_} _ {_} _ _.

CMRAs whose core is total

The function core may return a dummy when used on CMRAs without total core.
Class CMRATotal (A : cmraT) := cmra_total (x : A) : is_Some (pcore x).

Class Core (A : Type) := core : A A.
Instance: Params (@core) 2.

Instance core' `{PCore A} : Core A := λ x, from_option id x (pcore x).
Arguments core' _ _ _ /.

CMRAs with a unit element

We use the notation ∅ because for most instances (maps, sets, etc) the `empty' element is the unit.
Record UCMRAMixin A `{Dist A, Equiv A, PCore A, Op A, Valid A, Empty A} := {
  mixin_ucmra_unit_valid : ;
  mixin_ucmra_unit_left_id : LeftId (≡) (⋅);
  mixin_ucmra_unit_timeless : Timeless ;
  mixin_ucmra_pcore_unit : pcore Some
}.

Structure ucmraT := UCMRAT' {
  ucmra_car :> Type;
  ucmra_equiv : Equiv ucmra_car;
  ucmra_dist : Dist ucmra_car;
  ucmra_compl : Compl ucmra_car;
  ucmra_pcore : PCore ucmra_car;
  ucmra_op : Op ucmra_car;
  ucmra_valid : Valid ucmra_car;
  ucmra_validN : ValidN ucmra_car;
  ucmra_stepN : StepN ucmra_car;
  ucmra_empty : Empty ucmra_car;
  ucmra_cofe_mixin : CofeMixin ucmra_car;
  ucmra_cmra_mixin : CMRAMixin ucmra_car;
  ucmra_mixin : UCMRAMixin ucmra_car;
  _ : Type;
}.
Arguments UCMRAT' _ {_ _ _ _ _ _ _ _ _} _ _ _ _.
Notation UCMRAT A m m' m'' := (UCMRAT' A m m' m'' A).
Arguments ucmra_car : simpl never.
Arguments ucmra_equiv : simpl never.
Arguments ucmra_dist : simpl never.
Arguments ucmra_compl : simpl never.
Arguments ucmra_pcore : simpl never.
Arguments ucmra_op : simpl never.
Arguments ucmra_valid : simpl never.
Arguments ucmra_validN : simpl never.
Arguments ucmra_stepN : simpl never.
Arguments ucmra_cofe_mixin : simpl never.
Arguments ucmra_cmra_mixin : simpl never.
Arguments ucmra_mixin : simpl never.
Add Printing Constructor ucmraT.
Hint Extern 0 (Empty _) ⇒ eapply (@ucmra_empty _) : typeclass_instances.
Coercion ucmra_cofeC (A : ucmraT) : cofeT := CofeT A (ucmra_cofe_mixin A).
Canonical Structure ucmra_cofeC.
Coercion ucmra_cmraR (A : ucmraT) : cmraT :=
  CMRAT A (ucmra_cofe_mixin A) (ucmra_cmra_mixin A).
Canonical Structure ucmra_cmraR.

Lifting properties from the mixin
Section ucmra_mixin.
  Context {A : ucmraT}.
  Implicit Types x y : A.
  Lemma ucmra_unit_valid : ( : A).
  Proof. apply (mixin_ucmra_unit_valid _ (ucmra_mixin A)). Qed.
  Global Instance ucmra_unit_left_id : LeftId (≡) (@op A _).
  Proof. apply (mixin_ucmra_unit_left_id _ (ucmra_mixin A)). Qed.
  Global Instance ucmra_unit_timeless : Timeless ( : A).
  Proof. apply (mixin_ucmra_unit_timeless _ (ucmra_mixin A)). Qed.
  Lemma ucmra_pcore_unit : pcore (:A) Some .
  Proof. apply (mixin_ucmra_pcore_unit _ (ucmra_mixin A)). Qed.
End ucmra_mixin.

Discrete CMRAs

Class CMRADiscrete (A : cmraT) := {
  cmra_discrete :> Discrete A;
  cmra_discrete_valid (x : A) : ✓{0} x x
}.

Morphisms

Class CMRAMonotone {A B : cmraT} (f : A B) := {
  cmra_monotone_ne n :> Proper (dist n ==> dist n) f;
  validN_preserving n x : ✓{n} x ✓{n} f x;
  cmra_monotone x y : x y f x f y
}.
Arguments validN_preserving {_ _} _ {_} _ _ _.
Arguments cmra_monotone {_ _} _ {_} _ _ _.

Properties

Section cmra.
Context {A : cmraT}.
Implicit Types x y z : A.
Implicit Types xs ys zs : list A.

Setoids

Global Instance cmra_pcore_ne' n : Proper (dist n ==> dist n) (@pcore A _).
Proof.
  intros x y Hxy. destruct (pcore x) as [cx|] eqn:?.
  { destruct (cmra_pcore_ne n x y cx) as (cy&->&->); auto. }
  destruct (pcore y) as [cy|] eqn:?; auto.
  destruct (cmra_pcore_ne n y x cy) as (cx&?&->); simplify_eq/=; auto.
Qed.
Lemma cmra_pcore_proper x y cx :
  x y pcore x = Some cx cy, pcore y = Some cy cx cy.
Proof.
  intros. destruct (cmra_pcore_ne 0 x y cx) as (cy&?&?); auto.
   cy; split; [done|apply equiv_distn].
  destruct (cmra_pcore_ne n x y cx) as (cy'&?&?); naive_solver.
Qed.
Global Instance cmra_pcore_proper' : Proper ((≡) ==> (≡)) (@pcore A _).
Proof. apply (ne_proper _). Qed.
Global Instance cmra_op_ne' n : Proper (dist n ==> dist n ==> dist n) (@op A _).
Proof. intros x1 x2 Hx y1 y2 Hy. by rewrite Hy (comm _ x1) Hx (comm _ y2). Qed.
Global Instance ra_op_proper' : Proper ((≡) ==> (≡) ==> (≡)) (@op A _).
Proof. apply (ne_proper_2 _). Qed.
Global Instance cmra_validN_ne' : Proper (dist n ==> iff) (@validN A _ n) | 1.
Proof. by split; apply cmra_validN_ne. Qed.
Global Instance cmra_validN_proper : Proper ((≡) ==> iff) (@validN A _ n) | 1.
Proof. by intros n x1 x2 Hx; apply cmra_validN_ne', equiv_dist. Qed.
Global Instance cmra_stepN_proper : Proper ((≡) ==> (≡) ==> impl) (@stepN A _ n) | 1.
Proof. intros n x1 x2 Hx y1 y2 Hy; apply cmra_stepN_ne; eapply equiv_dist; auto. Qed.

Global Instance cmra_valid_proper : Proper ((≡) ==> iff) (@valid A _).
Proof.
  intros x y Hxy; rewrite !cmra_valid_validN.
  by split⇒ ? n; [rewrite -Hxy|rewrite Hxy].
Qed.
Global Instance cmra_includedN_ne n :
  Proper (dist n ==> dist n ==> iff) (@includedN A _ _ n) | 1.
Proof.
  intros x x' Hx y y' Hy.
  by split; intros [z ?]; z; [rewrite -Hx -Hy|rewrite Hx Hy].
Qed.
Global Instance cmra_includedN_proper n :
  Proper ((≡) ==> (≡) ==> iff) (@includedN A _ _ n) | 1.
Proof.
  intros x x' Hx y y' Hy; revert Hx Hy; rewrite !equiv_distHx Hy.
  by rewrite (Hx n) (Hy n).
Qed.
Global Instance cmra_included_proper :
  Proper ((≡) ==> (≡) ==> iff) (@included A _ _) | 1.
Proof.
  intros x x' Hx y y' Hy.
  by split; intros [z ?]; z; [rewrite -Hx -Hy|rewrite Hx Hy].
Qed.
Global Instance cmra_opM_ne n : Proper (dist n ==> dist n ==> dist n) (@opM A).
Proof. destruct 2; by cofe_subst. Qed.
Global Instance cmra_opM_proper : Proper ((≡) ==> (≡) ==> (≡)) (@opM A).
Proof. destruct 2; by setoid_subst. Qed.

Op

Lemma cmra_opM_assoc x y mz : (x y) ⋅? mz x (y ⋅? mz).
Proof. destruct mz; by rewrite /= -?assoc. Qed.

Validity

Lemma cmra_validN_le n n' x : ✓{n} x n' n ✓{n'} x.
Proof. induction 2; eauto using cmra_validN_S. Qed.
Lemma cmra_valid_op_l x y : (x y) x.
Proof. rewrite !cmra_valid_validN; eauto using cmra_validN_op_l. Qed.
Lemma cmra_validN_op_r n x y : ✓{n} (x y) ✓{n} y.
Proof. rewrite (comm _ x); apply cmra_validN_op_l. Qed.
Lemma cmra_valid_op_r x y : (x y) y.
Proof. rewrite !cmra_valid_validN; eauto using cmra_validN_op_r. Qed.

Core

Lemma cmra_pcore_l' x cx : pcore x Some cx cx x x.
Proof. intros (cx'&?&->)%equiv_Some_inv_r'. by apply cmra_pcore_l. Qed.
Lemma cmra_pcore_r x cx : pcore x = Some cx x cx x.
Proof. intros. rewrite comm. by apply cmra_pcore_l. Qed.
Lemma cmra_pcore_r' x cx : pcore x Some cx x cx x.
Proof. intros (cx'&?&->)%equiv_Some_inv_r'. by apply cmra_pcore_r. Qed.
Lemma cmra_pcore_idemp' x cx : pcore x Some cx pcore cx Some cx.
Proof. intros (cx'&?&->)%equiv_Some_inv_r'. eauto using cmra_pcore_idemp. Qed.
Lemma cmra_pcore_dup x cx : pcore x = Some cx cx cx cx.
Proof. intros; symmetry; eauto using cmra_pcore_r', cmra_pcore_idemp. Qed.
Lemma cmra_pcore_dup' x cx : pcore x Some cx cx cx cx.
Proof. intros; symmetry; eauto using cmra_pcore_r', cmra_pcore_idemp'. Qed.
Lemma cmra_pcore_validN n x cx : ✓{n} x pcore x = Some cx ✓{n} cx.
Proof.
  intros Hvx Hx%cmra_pcore_l. move: Hvx; rewrite -Hx. apply cmra_validN_op_l.
Qed.
Lemma cmra_pcore_valid x cx : x pcore x = Some cx cx.
Proof.
  intros Hv Hx%cmra_pcore_l. move: Hv; rewrite -Hx. apply cmra_valid_op_l.
Qed.

Persistent elements

Lemma persistent_dup x `{!Persistent x} : x x x.
Proof. by apply cmra_pcore_dup' with x. Qed.

Exclusive elements

Lemma exclusiveN_l n x `{!Exclusive x} y : ✓{n} (x y) False.
Proof. intros ?%cmra_validN_le%exclusive0_l; auto with arith. Qed.
Lemma exclusiveN_r n x `{!Exclusive x} y : ✓{n} (y x) False.
Proof. rewrite comm. by apply exclusiveN_l. Qed.
Lemma exclusive_l x `{!Exclusive x} y : (x y) False.
Proof. by move /cmra_valid_validN /(_ 0) /exclusive0_l. Qed.
Lemma exclusive_r x `{!Exclusive x} y : (y x) False.
Proof. rewrite comm. by apply exclusive_l. Qed.
Lemma exclusiveN_opM n x `{!Exclusive x} my : ✓{n} (x ⋅? my) my = None.
Proof. destruct my. move⇒ /(exclusiveN_l _ x) []. done. Qed.

StepN

Lemma cmra_stepN_le n n' x x' : x _(n) x' n' n x _(n') x'.
Proof. induction 2; eauto using cmra_stepN_S. Qed.

Order

Lemma cmra_included_includedN n x y : x y x ≼{n} y.
Proof. intros [z ->]. by z. Qed.
Global Instance cmra_includedN_trans n : Transitive (@includedN A _ _ n).
Proof.
  intros x y z [z1 Hy] [z2 Hz]; (z1 z2). by rewrite assoc -Hy -Hz.
Qed.
Global Instance cmra_included_trans: Transitive (@included A _ _).
Proof.
  intros x y z [z1 Hy] [z2 Hz]; (z1 z2). by rewrite assoc -Hy -Hz.
Qed.
Lemma cmra_validN_includedN n x y : ✓{n} y x ≼{n} y ✓{n} x.
Proof. intros Hyv [z ?]; cofe_subst y; eauto using cmra_validN_op_l. Qed.
Lemma cmra_validN_included n x y : ✓{n} y x y ✓{n} x.
Proof. intros Hyv [z ?]; setoid_subst; eauto using cmra_validN_op_l. Qed.
Lemma cmra_valid_included x y : y x y x.
Proof. intros Hyv [z ?]; setoid_subst; eauto using cmra_valid_op_l. Qed.

Lemma cmra_includedN_S n x y : x ≼{S n} y x ≼{n} y.
Proof. by intros [z Hz]; z; apply dist_S. Qed.
Lemma cmra_includedN_le n n' x y : x ≼{n} y n' n x ≼{n'} y.
Proof. induction 2; auto using cmra_includedN_S. Qed.

Lemma cmra_includedN_l n x y : x ≼{n} x y.
Proof. by y. Qed.
Lemma cmra_included_l x y : x x y.
Proof. by y. Qed.
Lemma cmra_includedN_r n x y : y ≼{n} x y.
Proof. rewrite (comm op); apply cmra_includedN_l. Qed.
Lemma cmra_included_r x y : y x y.
Proof. rewrite (comm op); apply cmra_included_l. Qed.

Lemma cmra_pcore_mono' x y cx :
  x y pcore x Some cx cy, pcore y = Some cy cx cy.
Proof.
  intros ? (cx'&?&Hcx)%equiv_Some_inv_r'.
  destruct (cmra_pcore_mono x y cx') as (cy&->&?); auto.
   cy; by rewrite Hcx.
Qed.
Lemma cmra_pcore_monoN' n x y cx :
  x ≼{n} y pcore x ≡{n}≡ Some cx cy, pcore y = Some cy cx ≼{n} cy.
Proof.
  intros [z Hy] (cx'&?&Hcx)%dist_Some_inv_r'.
  destruct (cmra_pcore_mono x (x z) cx')
    as (cy&Hxy&?); auto using cmra_included_l.
  assert (pcore y ≡{n}≡ Some cy) as (cy'&?&Hcy')%dist_Some_inv_r'.
  { by rewrite Hy Hxy. }
   cy'; split; first done.
  rewrite Hcx -Hcy'; auto using cmra_included_includedN.
Qed.
Lemma cmra_included_pcore x cx : pcore x = Some cx cx x.
Proof. x. by rewrite cmra_pcore_l. Qed.
Lemma cmra_monoN_l n x y z : x ≼{n} y z x ≼{n} z y.
Proof. by intros [z1 Hz1]; z1; rewrite Hz1 (assoc op). Qed.
Lemma cmra_mono_l x y z : x y z x z y.
Proof. by intros [z1 Hz1]; z1; rewrite Hz1 (assoc op). Qed.
Lemma cmra_monoN_r n x y z : x ≼{n} y x z ≼{n} y z.
Proof. by intros; rewrite -!(comm _ z); apply cmra_monoN_l. Qed.
Lemma cmra_mono_r x y z : x y x z y z.
Proof. by intros; rewrite -!(comm _ z); apply cmra_mono_l. Qed.

Lemma cmra_included_dist_l n x1 x2 x1' :
  x1 x2 x1' ≡{n}≡ x1 x2', x1' x2' x2' ≡{n}≡ x2.
Proof.
  intros [z Hx2] Hx1; (x1' z); split; auto using cmra_included_l.
  by rewrite Hx1 Hx2.
Qed.

Total core

Section total_core.
  Context `{CMRATotal A}.

  Lemma cmra_core_l x : core x x x.
  Proof.
    destruct (cmra_total x) as [cx Hcx]. by rewrite /core /= Hcx cmra_pcore_l.
  Qed.
  Lemma cmra_core_idemp x : core (core x) core x.
  Proof.
    destruct (cmra_total x) as [cx Hcx]. by rewrite /core /= Hcx cmra_pcore_idemp.
  Qed.
  Lemma cmra_core_mono x y : x y core x core y.
  Proof.
    intros; destruct (cmra_total x) as [cx Hcx].
    destruct (cmra_pcore_mono x y cx) as (cy&Hcy&?); auto.
    by rewrite /core /= Hcx Hcy.
  Qed.
  Lemma cmra_core_distrib n x y:
    ✓{n} (x y) core (core x core y) ≡{n}≡ core x core y.
  Proof.
    destruct (cmra_total x) as [cx Hcx].
    destruct (cmra_total y) as [cy Hcy].
    intros (cxy&Hcxy&Heq)%cmra_pcore_distrib; eauto.
    rewrite /core /= Hcx Hcy //= -Heq.
    destruct (cmra_total cxy) as [ccxy Hccxy].
    rewrite Hccxy //=.
    apply equiv_dist.
    eapply cmra_pcore_idemp in Hcxy.
    rewrite Hccxy in Hcxy. inversion Hcxy; eauto.
  Qed.

  Global Instance cmra_core_ne n : Proper (dist n ==> dist n) (@core A _).
  Proof.
    intros x y Hxy. destruct (cmra_total x) as [cx Hcx].
    by rewrite /core /= -Hxy Hcx.
  Qed.
  Global Instance cmra_core_proper : Proper ((≡) ==> (≡)) (@core A _).
  Proof. apply (ne_proper _). Qed.

  Lemma cmra_core_r x : x core x x.
  Proof. by rewrite (comm _ x) cmra_core_l. Qed.
  Lemma cmra_core_dup x : core x core x core x.
  Proof. by rewrite -{3}(cmra_core_idemp x) cmra_core_r. Qed.
  Lemma cmra_core_validN n x : ✓{n} x ✓{n} core x.
  Proof. rewrite -{1}(cmra_core_l x); apply cmra_validN_op_l. Qed.
  Lemma cmra_core_valid x : x core x.
  Proof. rewrite -{1}(cmra_core_l x); apply cmra_valid_op_l. Qed.

  Lemma persistent_total x : Persistent x core x x.
  Proof.
    split; [intros; by rewrite /core /= (persistent x)|].
    rewrite /Persistent /core /=.
    destruct (cmra_total x) as [? ->]. by constructor.
  Qed.
  Lemma persistent_core x `{!Persistent x} : core x x.
  Proof. by apply persistent_total. Qed.

  Global Instance cmra_core_persistent x : Persistent (core x).
  Proof.
    destruct (cmra_total x) as [cx Hcx].
    rewrite /Persistent /core /= Hcx /=. eauto using cmra_pcore_idemp.
  Qed.

  Lemma cmra_included_core x : core x x.
  Proof. by x; rewrite cmra_core_l. Qed.
  Global Instance cmra_includedN_preorder n : PreOrder (@includedN A _ _ n).
  Proof.
    split; [|apply _]. by intros x; (core x); rewrite cmra_core_r.
  Qed.
  Global Instance cmra_included_preorder : PreOrder (@included A _ _).
  Proof.
    split; [|apply _]. by intros x; (core x); rewrite cmra_core_r.
  Qed.
  Lemma cmra_core_monoN n x y : x ≼{n} y core x ≼{n} core y.
  Proof.
    intros [z ->].
    apply cmra_included_includedN, cmra_core_mono, cmra_included_l.
  Qed.
End total_core.

Timeless

Lemma cmra_timeless_included_l x y : Timeless x ✓{0} y x ≼{0} y x y.
Proof.
  intros ?? [x' ?].
  destruct (cmra_extend 0 y x x') as ([z z']&Hy&Hz&Hz'); auto; simpl in ×.
  by z'; rewrite Hy (timeless x z).
Qed.
Lemma cmra_timeless_included_r n x y : Timeless y x ≼{0} y x ≼{n} y.
Proof. intros ? [x' ?]. x'. by apply equiv_dist, (timeless y). Qed.
Lemma cmra_op_timeless x1 x2 :
   (x1 x2) Timeless x1 Timeless x2 Timeless (x1 x2).
Proof.
  intros ??? z Hz.
  destruct (cmra_extend 0 z x1 x2) as ([y1 y2]&Hz'&?&?); auto; simpl in ×.
  { rewrite -?Hz. by apply cmra_valid_validN. }
  by rewrite Hz' (timeless x1 y1) // (timeless x2 y2).
Qed.

Discrete

Lemma cmra_discrete_valid_iff `{CMRADiscrete A} n x : x ✓{n} x.
Proof.
  split; first by rewrite cmra_valid_validN.
  eauto using cmra_discrete_valid, cmra_validN_le with lia.
Qed.
Lemma cmra_discrete_included_iff `{Discrete A} n x y : x y x ≼{n} y.
Proof.
  split; first by apply cmra_included_includedN.
  intros [z ->%(timeless_iff _ _)]; eauto using cmra_included_l.
Qed.
End cmra.

Properties about CMRAs with a unit element

Section ucmra.
  Context {A : ucmraT}.
  Implicit Types x: A.

  Global Instance ucmra_unit_inhabited : Inhabited A := populate .

  Lemma ucmra_unit_validN n : ✓{n} (:A).
  Proof. apply cmra_valid_validN, ucmra_unit_valid. Qed.
  Lemma ucmra_unit_leastN n x : ≼{n} x.
  Proof. by x; rewrite left_id. Qed.
  Lemma ucmra_unit_least x : x.
  Proof. by x; rewrite left_id. Qed.
  Global Instance ucmra_unit_right_id : RightId (≡) (@op A _).
  Proof. by intros x; rewrite (comm op) left_id. Qed.
  Global Instance ucmra_unit_persistent : Persistent (:A).
  Proof. apply ucmra_pcore_unit. Qed.

  Lemma ucmra_unit_unique x y:
    ( x', x x' x')
    ( x', y x' x')
    x y.
  Proof.
    intros Hu1 Hu2. specialize (Hu1 y). specialize (Hu2 x).
    rewrite -Hu1. rewrite -{1}Hu2. by rewrite comm.
  Qed.

  Global Instance cmra_unit_total : CMRATotal A.
  Proof.
    intros x. destruct (cmra_pcore_mono' x ) as (cx&->&?);
      eauto using ucmra_unit_least, (persistent ).
  Qed.

Transporting a UCMRA equality

  Definition ucmra_transport {A B : ucmraT} (H : A = B) (x : A) : B :=
    eq_rect A id x _ H.

  Section ucmra_transport.
    Context {B : ucmraT} (H : A = B).
    Notation T := (ucmra_transport H).
    Global Instance ucmra_transport_ne n : Proper (dist n ==> dist n) T.
    Proof. by intros ???; destruct H. Qed.
    Global Instance ucmra_transport_proper : Proper ((≡) ==> (≡)) T.
    Proof. by intros ???; destruct H. Qed.
    Lemma ucmra_transport_op x y : T (x y) = T x T y.
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_core x : T (core x) = core (T x).
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_validN n x : ✓{n} T x ✓{n} x.
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_valid x : T x x.
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_stepN n x y : (T x _(n) T y) (x _(n) y).
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_stepN_adj n x y : (T x _(n) y) (x _(n) (ucmra_transport (eq_sym H) y)).
    Proof. by destruct H. Qed.
    Global Instance ucmra_transport_timeless x : Timeless x Timeless (T x).
    Proof. by destruct H. Qed.
    Global Instance ucmra_transport_persistent x : Persistent x Persistent (T x).
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_unit: T .
    Proof. by destruct H. Qed.
    Lemma ucmra_transport_sym_inv (x: A):
      ucmra_transport (eq_sym H) (ucmra_transport H (x)) = x.
    Proof.
      destruct H. auto.
    Qed.
  End ucmra_transport.
End ucmra.
Hint Immediate cmra_unit_total.

Constructing a CMRA with total core

Section cmra_total.
  Context A `{Dist A, Equiv A, PCore A, Op A, Valid A, ValidN A, StepN A}.
  Context (total : x, is_Some (pcore x)).
  Context (op_ne : n (x : A), Proper (dist n ==> dist n) (op x)).
  Context (core_ne : n, Proper (dist n ==> dist n) (@core A _)).
  Context (validN_ne : n, Proper (dist n ==> impl) (@validN A _ n)).
  Context (valid_validN : (x : A), x n, ✓{n} x).
  Context (validN_S : n (x : A), ✓{S n} x ✓{n} x).
  Context (stepN_ne : n, Proper (dist n ==> dist n ==> impl) (@stepN A _ n)).
  Context (stepN_S : n (x y : A), x _(S n) y x _(n) y).
  Context (op_assoc : Assoc (≡) (@op A _)).
  Context (op_comm : Comm (≡) (@op A _)).
  Context (core_l : x : A, core x x x).
  Context (core_idemp : x : A, core (core x) core x).
  Context (core_mono : x y : A, x y core x core y).
  Context (core_preserving : x y : A, x y core x core y).
  Context (core_distrib : n (x y : A),
    ✓{n} (x y) core (core x core y) ≡{n}≡ core x core y).
  Context (validN_op_l : n (x y : A), ✓{n} (x y) ✓{n} x).
  Context (extend : n (x y1 y2 : A),
    ✓{n} x x ≡{n}≡ y1 y2
    { z | x z.1 z.2 z.1 ≡{n}≡ y1 z.2 ≡{n}≡ y2 }).
  Lemma cmra_total_mixin : CMRAMixin A.
  Proof.
    split; auto.
    - intros n x y ? Hcx%core_ne Hx; move: Hcx. rewrite /core /= Hx /=.
      case (total y)=> [cy ->]; eauto.
    - intros x cx Hcx. move: (core_l x). by rewrite /core /= Hcx.
    - intros x cx Hcx. move: (core_idemp x). rewrite /core /= Hcx /=.
      case (total cx)=>[ccx ->]; by constructor.
    - intros x y cx Hxy%core_mono Hx. move: Hxy.
      rewrite /core /= Hx /=. case (total y)=> [cy ->]; eauto.
    - intros n x y cx cy Hxy%core_distrib Hx Hy. move: Hxy.
      rewrite /core /= Hx Hy /=.
      case (total (cx cy))=> [cxy ->] //= Hxy. eauto.
  Qed.
End cmra_total.

Properties about monotone functions

Instance cmra_monotone_id {A : cmraT} : CMRAMonotone (@id A).
Proof. repeat split; by try apply _. Qed.
Instance cmra_monotone_compose {A B C : cmraT} (f : A B) (g : B C) :
  CMRAMonotone f CMRAMonotone g CMRAMonotone (g f).
Proof.
  split.
  - apply _.
  - moven x Hx /=. by apply validN_preserving, validN_preserving.
  - movex y Hxy /=. by apply cmra_monotone, cmra_monotone.
Qed.

Section cmra_monotone.
  Context {A B : cmraT} (f : A B) `{!CMRAMonotone f}.
  Global Instance cmra_monotone_proper : Proper ((≡) ==> (≡)) f := ne_proper _.
  Lemma cmra_monotoneN n x y : x ≼{n} y f x ≼{n} f y.
  Proof.
    intros [z ->].
    apply cmra_included_includedN, (cmra_monotone f), cmra_included_l.
  Qed.
  Lemma valid_preserving x : x f x.
  Proof. rewrite !cmra_valid_validN; eauto using validN_preserving. Qed.
End cmra_monotone.

Functors
Structure rFunctor := RFunctor {
  rFunctor_car : cofeT cofeT cmraT;
  rFunctor_map {A1 A2 B1 B2} :
    ((A2 -n> A1) × (B1 -n> B2)) rFunctor_car A1 B1 -n> rFunctor_car A2 B2;
  rFunctor_ne A1 A2 B1 B2 n :
    Proper (dist n ==> dist n) (@rFunctor_map A1 A2 B1 B2);
  rFunctor_id {A B} (x : rFunctor_car A B) : rFunctor_map (cid,cid) x x;
  rFunctor_compose {A1 A2 A3 B1 B2 B3}
      (f : A2 -n> A1) (g : A3 -n> A2) (f' : B1 -n> B2) (g' : B2 -n> B3) x :
    rFunctor_map (fg, g'f') x rFunctor_map (g,g') (rFunctor_map (f,f') x);
  rFunctor_mono {A1 A2 B1 B2} (fg : (A2 -n> A1) × (B1 -n> B2)) :
    CMRAMonotone (rFunctor_map fg)
}.
Existing Instances rFunctor_ne rFunctor_mono.
Instance: Params (@rFunctor_map) 5.

Class rFunctorContractive (F : rFunctor) :=
  rFunctor_contractive A1 A2 B1 B2 :> Contractive (@rFunctor_map F A1 A2 B1 B2).

Definition rFunctor_diag (F: rFunctor) (A: cofeT) : cmraT := rFunctor_car F A A.
Coercion rFunctor_diag : rFunctor >-> Funclass.

Program Definition constRF (B : cmraT) : rFunctor :=
  {| rFunctor_car A1 A2 := B; rFunctor_map A1 A2 B1 B2 f := cid |}.
Solve Obligations with done.

Instance constRF_contractive B : rFunctorContractive (constRF B).
Proof. rewrite /rFunctorContractive; apply _. Qed.

Structure urFunctor := URFunctor {
  urFunctor_car : cofeT cofeT ucmraT;
  urFunctor_map {A1 A2 B1 B2} :
    ((A2 -n> A1) × (B1 -n> B2)) urFunctor_car A1 B1 -n> urFunctor_car A2 B2;
  urFunctor_ne A1 A2 B1 B2 n :
    Proper (dist n ==> dist n) (@urFunctor_map A1 A2 B1 B2);
  urFunctor_id {A B} (x : urFunctor_car A B) : urFunctor_map (cid,cid) x x;
  urFunctor_compose {A1 A2 A3 B1 B2 B3}
      (f : A2 -n> A1) (g : A3 -n> A2) (f' : B1 -n> B2) (g' : B2 -n> B3) x :
    urFunctor_map (fg, g'f') x urFunctor_map (g,g') (urFunctor_map (f,f') x);
  urFunctor_mono {A1 A2 B1 B2} (fg : (A2 -n> A1) × (B1 -n> B2)) :
    CMRAMonotone (urFunctor_map fg)
}.
Existing Instances urFunctor_ne urFunctor_mono.
Instance: Params (@urFunctor_map) 5.

Class urFunctorContractive (F : urFunctor) :=
  urFunctor_contractive A1 A2 B1 B2 :> Contractive (@urFunctor_map F A1 A2 B1 B2).

Definition urFunctor_diag (F: urFunctor) (A: cofeT) : ucmraT := urFunctor_car F A A.
Coercion urFunctor_diag : urFunctor >-> Funclass.

Program Definition constURF (B : ucmraT) : urFunctor :=
  {| urFunctor_car A1 A2 := B; urFunctor_map A1 A2 B1 B2 f := cid |}.
Solve Obligations with done.

Instance constURF_contractive B : urFunctorContractive (constURF B).
Proof. rewrite /urFunctorContractive; apply _. Qed.

Transporting a CMRA equality

Definition cmra_transport {A B : cmraT} (H : A = B) (x : A) : B :=
  eq_rect A id x _ H.

Section cmra_transport.
  Context {A B : cmraT} (H : A = B).
  Notation T := (cmra_transport H).
  Global Instance cmra_transport_ne n : Proper (dist n ==> dist n) T.
  Proof. by intros ???; destruct H. Qed.
  Global Instance cmra_transport_proper : Proper ((≡) ==> (≡)) T.
  Proof. by intros ???; destruct H. Qed.
  Lemma cmra_transport_op x y : T (x y) = T x T y.
  Proof. by destruct H. Qed.
  Lemma cmra_transport_core x : T (core x) = core (T x).
  Proof. by destruct H. Qed.
  Lemma cmra_transport_validN n x : ✓{n} T x ✓{n} x.
  Proof. by destruct H. Qed.
  Lemma cmra_transport_valid x : T x x.
  Proof. by destruct H. Qed.
  Lemma cmra_transport_stepN n x y : (T x _(n) T y) (x _(n) y).
  Proof. by destruct H. Qed.
  Lemma cmra_transport_stepN_adj n x y : (T x _(n) y) (x _(n) (cmra_transport (eq_sym H) y)).
  Proof. by destruct H. Qed.
  Global Instance cmra_transport_timeless x : Timeless x Timeless (T x).
  Proof. by destruct H. Qed.
  Global Instance cmra_transport_persistent x : Persistent x Persistent (T x).
  Proof. by destruct H. Qed.
  Lemma cmra_transport_sym_inv (x: A):
    cmra_transport (eq_sym H) (cmra_transport H (x)) = x.
  Proof.
    destruct H. auto.
  Qed.
End cmra_transport.

Instances

Discrete CMRA

Record RAMixin A `{Equiv A, PCore A, Op A, Valid A, Step A} := {
  
  ra_op_proper (x : A) : Proper ((≡) ==> (≡)) (op x);
  ra_core_proper x y cx :
    x y pcore x = Some cx cy, pcore y = Some cy cx cy;
  ra_validN_proper : Proper ((≡) ==> impl) valid;
  
  ra_assoc : Assoc (≡) (⋅);
  ra_comm : Comm (≡) (⋅);
  ra_pcore_l x cx : pcore x = Some cx cx x x;
  ra_pcore_idemp x cx : pcore x = Some cx pcore cx Some cx;
  ra_pcore_mono x y cx :
    x y pcore x = Some cx cy, pcore y = Some cy cx cy;
  ra_pcore_distrib x y cx cy :
    ✓(x y)
    pcore x = Some cx
    pcore y = Some cy
    pcore (cx cy) Some (cx cy);
  ra_valid_op_l x y : (x y) x;
  ra_step_e :> Proper ((≡) ==> (≡) ==> impl) step
}.

Section discrete.
  Context `{Equiv A, PCore A, Op A, Valid A, Step A, @Equivalence A (≡)}.
  Context (ra_mix : RAMixin A).
  Existing Instances discrete_dist discrete_compl.

  Instance discrete_validN : ValidN A := λ n x, x.
  Instance discrete_stepN : StepN A := λ n x y, x y.
  Definition discrete_cmra_mixin : CMRAMixin A.
  Proof.
    destruct ra_mix; split; try done.
    - intros x; split; first done. by move⇒ /(_ 0).
    - intros n x1 y1 x2 y2 ???.
      assert (pcore (x2 y2) Some (x2 y2)) as Hequiv; eauto.
      inversion Hequiv; subst; eauto.
    - intros n x y1 y2 ??. by (y1,y2).
  Qed.
End discrete.

Notation discreteR A ra_mix :=
  (CMRAT A discrete_cofe_mixin (discrete_cmra_mixin ra_mix)).
Notation discreteUR A ra_mix ucmra_mix :=
  (UCMRAT A discrete_cofe_mixin (discrete_cmra_mixin ra_mix) ucmra_mix).

Global Instance discrete_cmra_discrete `{Equiv A, PCore A, Op A, Valid A, Step A,
  @Equivalence A (≡)} (ra_mix : RAMixin A) : CMRADiscrete (discreteR A ra_mix).
Proof. split. apply _. done. Qed.

Section ra_total.
  Context A `{Equiv A, PCore A, Op A, Valid A, Step A}.
  Context (total : x, is_Some (pcore x)).
  Context (op_proper : (x : A), Proper ((≡) ==> (≡)) (op x)).
  Context (core_proper: Proper ((≡) ==> (≡)) (@core A _)).
  Context (valid_proper : Proper ((≡) ==> impl) (@valid A _)).
  Context (step_proper : Proper ((≡) ==> (≡) ==> impl) (@step A _)).
  Context (op_assoc : Assoc (≡) (@op A _)).
  Context (op_comm : Comm (≡) (@op A _)).
  Context (core_l : x : A, core x x x).
  Context (core_idemp : x : A, core (core x) core x).
  Context (core_mono : x y : A, x y core x core y).
  Context (core_distrib : x y: A, (x y) core (core x core y) core x core y).
  Context (valid_op_l : x y : A, (x y) x).
  Lemma ra_total_mixin : RAMixin A.
  Proof.
    split; auto.
    - intros x y ? Hcx%core_proper Hx; move: Hcx. rewrite /core /= Hx /=.
      case (total y)=> [cy ->]; eauto.
    - intros x cx Hcx. move: (core_l x). by rewrite /core /= Hcx.
    - intros x cx Hcx. move: (core_idemp x). rewrite /core /= Hcx /=.
      case (total cx)=>[ccx ->]; by constructor.
    - intros x y cx Hxy%core_mono Hx. move: Hxy.
      rewrite /core /= Hx /=. case (total y)=> [cy ->]; eauto.
    - intros x y cx cy Hxy%core_distrib Hx Hy. move: Hxy.
      rewrite /core /= Hx Hy /=.
      case (total (cx cy))=> [cxy ->] //= Hxy.
      constructor; eauto.
  Qed.
End ra_total.

CMRA for the unit type

Section unit.
  Instance unit_valid : Valid () := λ x, True.
  Instance unit_validN : ValidN () := λ n x, True.
  Instance unit_pcore : PCore () := λ x, Some x.
  Instance unit_op : Op () := λ x y, ().
  Instance unit_step : StepN () := λ n x y, True.
  Lemma unit_cmra_mixin : CMRAMixin ().
  Proof. apply discrete_cmra_mixin, ra_total_mixin; by eauto. Qed.
  Canonical Structure unitR : cmraT := CMRAT () unit_cofe_mixin unit_cmra_mixin.

  Instance unit_empty : Empty () := ().
  Lemma unit_ucmra_mixin : UCMRAMixin ().
  Proof. done. Qed.
  Canonical Structure unitUR : ucmraT :=
    UCMRAT () unit_cofe_mixin unit_cmra_mixin unit_ucmra_mixin.

  Global Instance unit_cmra_discrete : CMRADiscrete unitR.
  Proof. done. Qed.
  Global Instance unit_persistent (x : ()) : Persistent x.
  Proof. by constructor. Qed.
End unit.

Natural numbers

Section nat.
  Instance nat_valid : Valid nat := λ x, True.
  Instance nat_validN : ValidN nat := λ n x, True.
  Instance nat_pcore : PCore nat := λ x, Some 0.
  Instance nat_op : Op nat := plus.
  Instance nat_stepN : StepN nat := λ n x y, True.
  Definition nat_op_plus x y : x y = x + y := eq_refl.
  Lemma nat_included (x y : nat) : x y x y.
  Proof.
    split.
    - intros [z ->]; unfold op, nat_op; lia.
    - (y - x). by apply le_plus_minus.
  Qed.
  Lemma nat_ra_mixin : RAMixin nat.
  Proof.
    apply ra_total_mixin; try by eauto.
    - solve_proper.
    - intros x y z. apply Nat.add_assoc.
    - intros x y. apply Nat.add_comm.
    - by 0.
  Qed.
  Canonical Structure natR : cmraT := discreteR nat nat_ra_mixin.

  Instance nat_empty : Empty nat := 0.
  Lemma nat_ucmra_mixin : UCMRAMixin nat.
  Proof. split; apply _ || done. Qed.
  Canonical Structure natUR : ucmraT :=
    discreteUR nat nat_ra_mixin nat_ucmra_mixin.

  Global Instance nat_cmra_discrete : CMRADiscrete natR.
  Proof. constructor; apply _ || done. Qed.
End nat.

Definition mnat := nat.

Section mnat.
  Instance mnat_valid : Valid mnat := λ x, True.
  Instance mnat_validN : ValidN mnat := λ n x, True.
  Instance mnat_pcore : PCore mnat := Some.
  Instance mnat_op : Op mnat := Nat.max.
  Instance mnat_stepN : StepN nat := λ n x y, True.
  Definition mnat_op_max x y : x y = x `max` y := eq_refl.
  Lemma mnat_included (x y : mnat) : x y x y.
  Proof.
    split.
    - intros [z ->]; unfold op, mnat_op; lia.
    - y. by symmetry; apply Nat.max_r.
  Qed.
  Lemma mnat_ra_mixin : RAMixin mnat.
  Proof.
    apply ra_total_mixin; try by eauto.
    - solve_proper.
    - solve_proper.
    - intros x y z. apply Nat.max_assoc.
    - intros x y. apply Nat.max_comm.
    - intros x. apply Max.max_idempotent.
  Qed.
  Canonical Structure mnatR : cmraT := discreteR mnat mnat_ra_mixin.

  Instance mnat_empty : Empty mnat := 0.
  Lemma mnat_ucmra_mixin : UCMRAMixin mnat.
  Proof. split; apply _ || done. Qed.
  Canonical Structure mnatUR : ucmraT :=
    discreteUR mnat mnat_ra_mixin mnat_ucmra_mixin.

  Global Instance mnat_cmra_discrete : CMRADiscrete mnatR.
  Proof. constructor; apply _ || done. Qed.
  Global Instance mnat_persistent (x : mnat) : Persistent x.
  Proof. by constructor. Qed.
End mnat.

Product

Section prod.
  Context {A B : cmraT}.
  Local Arguments pcore _ _ !_ /.
  Local Arguments cmra_pcore _ !_/.

  Instance prod_op : Op (A × B) := λ x y, (x.1 y.1, x.2 y.2).
  Instance prod_pcore : PCore (A × B) := λ x,
    c1 pcore (x.1); c2 pcore (x.2); Some (c1, c2).
  Arguments prod_pcore !_ /.
  Instance prod_valid : Valid (A × B) := λ x, x.1 x.2.
  Instance prod_validN : ValidN (A × B) := λ n x, ✓{n} x.1 ✓{n} x.2.
  Instance prod_stepN : StepN (A × B) := λ n x y, x.1 _(n) y.1 x.2 _(n) y.2.
  Lemma prod_distrib n (x y : A × B) cx cy :
    ✓{n} (x y)
    pcore x = Some cx
    pcore y = Some cy
     cxy, pcore (cx cy) = Some cxy cxy ≡{n}≡ cx cy.
  Proof.
    destruct x as [x1 x2].
    destruct y as [y1 y2].
    intros (Hv1&Hv2) ? ?.
    simplify_option_eq.
    eapply cmra_pcore_distrib in Hv1; eauto.
    eapply cmra_pcore_distrib in Hv2; eauto.
    inversion Hv1 as (cxy1&Heqxy1&Hd1).
    inversion Hv2 as (cxy2&Heqxy2&Hd2).
    rewrite /= Heqxy1 Heqxy2; eauto.
     (cxy1, cxy2). simpl; split; eauto.
    by rewrite Hd1 Hd2.
  Qed.

  Lemma prod_pcore_Some (x cx : A × B) :
    pcore x = Some cx pcore (x.1) = Some (cx.1) pcore (x.2) = Some (cx.2).
  Proof. destruct x, cx; by intuition simplify_option_eq. Qed.
  Lemma prod_pcore_Some' (x cx : A × B) :
    pcore x Some cx pcore (x.1) Some (cx.1) pcore (x.2) Some (cx.2).
  Proof.
    split; [by intros (cx'&[-> ->]%prod_pcore_Some&->)%equiv_Some_inv_r'|].
    rewrite {3}/pcore /prod_pcore.     intros [Hx1 Hx2]; inversion_clear Hx1; simpl; inversion_clear Hx2.
    by constructor.
  Qed.

  Lemma prod_included (x y : A × B) : x y x.1 y.1 x.2 y.2.
  Proof.
    split; [intros [z Hz]; split; [ (z.1)| (z.2)]; apply Hz|].
    intros [[z1 Hz1] [z2 Hz2]]; (z1,z2); split; auto.
  Qed.
  Lemma prod_includedN (x y : A × B) n : x ≼{n} y x.1 ≼{n} y.1 x.2 ≼{n} y.2.
  Proof.
    split; [intros [z Hz]; split; [ (z.1)| (z.2)]; apply Hz|].
    intros [[z1 Hz1] [z2 Hz2]]; (z1,z2); split; auto.
  Qed.

  Definition prod_cmra_mixin : CMRAMixin (A × B).
  Proof.
    split; try apply _.
    - by intros n x y1 y2 [Hy1 Hy2]; split; rewrite /= ?Hy1 ?Hy2.
    - intros n x y cx; setoid_rewrite prod_pcore_Some⇒ -[??] [??].
      destruct (cmra_pcore_ne n (x.1) (y.1) (cx.1)) as (z1&->&?); auto.
      destruct (cmra_pcore_ne n (x.2) (y.2) (cx.2)) as (z2&->&?); auto.
       (z1,z2); repeat constructor; auto.
    - by intros n y1 y2 [Hy1 Hy2] [??]; split; rewrite /= -?Hy1 -?Hy2.
    - intros x; split.
      + intros [??] n; split; by apply cmra_valid_validN.
      + intros Hxy; split; apply cmra_valid_validNn; apply Hxy.
    - by intros n x [??]; split; apply cmra_validN_S.
    - by split; rewrite /= assoc.
    - by split; rewrite /= comm.
    - intros x y [??]%prod_pcore_Some;
        constructor; simpl; eauto using cmra_pcore_l.
    - intros x y; rewrite prod_pcore_Some prod_pcore_Some'.
      naive_solver eauto using cmra_pcore_idemp.
    - intros x y cx; rewrite prod_included prod_pcore_Some⇒ -[??] [??].
      destruct (cmra_pcore_mono (x.1) (y.1) (cx.1)) as (z1&?&?); auto.
      destruct (cmra_pcore_mono (x.2) (y.2) (cx.2)) as (z2&?&?); auto.
       (z1,z2). by rewrite prod_included prod_pcore_Some.
    - eapply prod_distrib.
    - intros n x y [??]; split; simpl in *; eauto using cmra_validN_op_l.
    - intros n x y1 y2 [??] [??]; simpl in ×.
      destruct (cmra_extend n (x.1) (y1.1) (y2.1)) as (z1&?&?&?); auto.
      destruct (cmra_extend n (x.2) (y1.2) (y2.2)) as (z2&?&?&?); auto.
      by ((z1.1,z2.1),(z1.2,z2.2)).
    - intros n x1 x2 [Hx1 Hx2] y1 y2 [Hy1 Hy2] [Hs1 Hs2];
        split; [ rewrite -Hx1 -Hy1 | rewrite -Hx2 -Hy2 ]; auto.
    - intros n x1 x2 [Hx1 Hx2].
        split; eapply cmra_stepN_S; eauto.
  Qed.
  Canonical Structure prodR :=
    CMRAT (A × B) prod_cofe_mixin prod_cmra_mixin.

  Lemma pair_op (a a' : A) (b b' : B) : (a, b) (a', b') = (a a', b b').
  Proof. done. Qed.

  Global Instance prod_cmra_total : CMRATotal A CMRATotal B CMRATotal prodR.
  Proof.
    intros H1 H2 [a b]. destruct (H1 a) as [ca ?], (H2 b) as [cb ?].
     (ca,cb); by simplify_option_eq.
  Qed.

  Global Instance prod_cmra_discrete :
    CMRADiscrete A CMRADiscrete B CMRADiscrete prodR.
  Proof. split. apply _. by intros ? []; split; apply cmra_discrete_valid. Qed.

  Global Instance pair_persistent x y :
    Persistent x Persistent y Persistent (x,y).
  Proof. by rewrite /Persistent prod_pcore_Some'. Qed.

  Global Instance pair_exclusive_l x y : Exclusive x Exclusive (x,y).
  Proof. by intros ?[][?%exclusive0_l]. Qed.
  Global Instance pair_exclusive_r x y : Exclusive y Exclusive (x,y).
  Proof. by intros ?[][??%exclusive0_l]. Qed.
End prod.

Arguments prodR : clear implicits.

Section prod_unit.
  Context {A B : ucmraT}.

  Instance prod_empty `{Empty A, Empty B} : Empty (A × B) := (, ).
  Lemma prod_ucmra_mixin : UCMRAMixin (A × B).
  Proof.
    split.
    - split; apply ucmra_unit_valid.
    - by split; rewrite /=left_id.
    - by intros ? [??]; split; apply (timeless _).
    - rewrite prod_pcore_Some'; split; apply (persistent _).
  Qed.
  Canonical Structure prodUR :=
    UCMRAT (A × B) prod_cofe_mixin prod_cmra_mixin prod_ucmra_mixin.

  Lemma pair_split (x : A) (y : B) : (x, y) (x, ) (, y).
  Proof. by rewrite pair_op left_id right_id. Qed.
End prod_unit.

Arguments prodUR : clear implicits.

Instance prod_map_cmra_monotone {A A' B B' : cmraT} (f : A A') (g : B B') :
  CMRAMonotone f CMRAMonotone g CMRAMonotone (prod_map f g).
Proof.
  split; first apply _.
  - by intros n x [??]; split; simpl; apply validN_preserving.
  - intros x y; rewrite !prod_included⇒ -[??] /=.
    by split; apply cmra_monotone.
Qed.

Program Definition prodRF (F1 F2 : rFunctor) : rFunctor := {|
  rFunctor_car A B := prodR (rFunctor_car F1 A B) (rFunctor_car F2 A B);
  rFunctor_map A1 A2 B1 B2 fg :=
    prodC_map (rFunctor_map F1 fg) (rFunctor_map F2 fg)
|}.
Next Obligation.
  intros F1 F2 A1 A2 B1 B2 n ???. by apply prodC_map_ne; apply rFunctor_ne.
Qed.
Next Obligation. by intros F1 F2 A B [??]; rewrite /= !rFunctor_id. Qed.
Next Obligation.
  intros F1 F2 A1 A2 A3 B1 B2 B3 f g f' g' [??]; simpl.
  by rewrite !rFunctor_compose.
Qed.

Instance prodRF_contractive F1 F2 :
  rFunctorContractive F1 rFunctorContractive F2
  rFunctorContractive (prodRF F1 F2).
Proof.
  intros ?? A1 A2 B1 B2 n ???;
    by apply prodC_map_ne; apply rFunctor_contractive.
Qed.

Program Definition prodURF (F1 F2 : urFunctor) : urFunctor := {|
  urFunctor_car A B := prodUR (urFunctor_car F1 A B) (urFunctor_car F2 A B);
  urFunctor_map A1 A2 B1 B2 fg :=
    prodC_map (urFunctor_map F1 fg) (urFunctor_map F2 fg)
|}.
Next Obligation.
  intros F1 F2 A1 A2 B1 B2 n ???. by apply prodC_map_ne; apply urFunctor_ne.
Qed.
Next Obligation. by intros F1 F2 A B [??]; rewrite /= !urFunctor_id. Qed.
Next Obligation.
  intros F1 F2 A1 A2 A3 B1 B2 B3 f g f' g' [??]; simpl.
  by rewrite !urFunctor_compose.
Qed.

Instance prodURF_contractive F1 F2 :
  urFunctorContractive F1 urFunctorContractive F2
  urFunctorContractive (prodURF F1 F2).
Proof.
  intros ?? A1 A2 B1 B2 n ???;
    by apply prodC_map_ne; apply urFunctor_contractive.
Qed.

CMRA for the option type

Section option.
  Context {A : cmraT}.
  Local Arguments core _ _ !_ /.
  Local Arguments pcore _ _ !_ /.

  Instance option_valid : Valid (option A) := λ mx,
    match mx with Some x x | NoneTrue end.
  Instance option_validN : ValidN (option A) := λ n mx,
    match mx with Some x✓{n} x | NoneTrue end.
  Instance option_stepN: StepN (option A) := λ n x y, True.
  Instance option_pcore : PCore (option A) := λ mx, Some (mx ≫= pcore).
  Arguments option_pcore !_ /.
  Instance option_op : Op (option A) := union_with (λ x y, Some (x y)).

  Definition Some_valid a : Some a a := reflexivity _.
  Definition Some_validN n a : ✓{n} Some a ✓{n} a := reflexivity _.
  Definition Some_op a b : Some (a b) = Some a Some b := eq_refl.
  Lemma Some_core `{CMRATotal A} a : Some (core a) = core (Some a).
  Proof. rewrite /core /=. by destruct (cmra_total a) as [? ->]. Qed.
  Lemma Some_op_opM x my : Some x my = Some (x ⋅? my).
  Proof. by destruct my. Qed.

  Lemma option_distrib n (mx my: option A):
    ✓{n} (mx my) core (core mx core my) ≡{n}≡ core mx core my.
  Proof.
    destruct mx as [x|];
    destruct my as [y|];
    rewrite /op //= {1}/core //= Some_validN.
    - specialize (cmra_pcore_distrib n x y);
      specialize (cmra_pcore_idemp x);
      specialize (cmra_pcore_idemp y).
      case (pcore x)=>[cx|]; case (pcore y)=>[cy|]; simpl; eauto.
      × intros ?? Hdistrib ?. edestruct Hdistrib as (?&->&?); eauto.
        econstructor; eauto.
      × intros. eapply equiv_dist; eauto.
      × intros. eapply equiv_dist; eauto.
    - intros. eapply equiv_dist.
      specialize (cmra_pcore_idemp x).
      case (pcore x); simpl; eauto.
    - intros. eapply equiv_dist.
      specialize (cmra_pcore_idemp y);
      case (pcore y); simpl; eauto.
  Qed.

  Lemma option_included (mx my : option A) :
    mx my mx = None x y, mx = Some x my = Some y (x y x y).
  Proof.
    split.
    - intros [mz Hmz].
      destruct mx as [x|]; [right|by left].
      destruct my as [y|]; [ x, y|destruct mz; inversion_clear Hmz].
      destruct mz as [z|]; inversion_clear Hmz; split_and?; auto;
        setoid_subst; eauto using cmra_included_l.
    - intros [->|(x&y&->&->&[[z Hz]|Hz])].
      + my. by destruct my.
      + (Some z); by constructor.
      + None; by constructor.
  Qed.

  Lemma option_cmra_mixin : CMRAMixin (option A).
  Proof.
    apply cmra_total_mixin.
    - eauto.
    - by intros n [x|]; destruct 1; constructor; cofe_subst.
    - destruct 1; by cofe_subst.
    - by destruct 1; rewrite /validN /option_validN //=; cofe_subst.
    - intros [x|]; [apply cmra_valid_validN|done].
    - intros n [x|]; unfold validN, option_validN; eauto using cmra_validN_S.
    - by intros n.
    - by intros n.
    - intros [x|] [y|] [z|]; constructor; rewrite ?assoc; auto.
    - intros [x|] [y|]; constructor; rewrite 1?comm; auto.
    - intros [x|]; simpl; auto.
      destruct (pcore x) as [cx|] eqn:?; constructor; eauto using cmra_pcore_l.
    - intros [x|]; simpl; auto.
      destruct (pcore x) as [cx|] eqn:?; simpl; eauto using cmra_pcore_idemp.
    - intros mx my; setoid_rewrite option_included.
      intros [->|(x&y&->&->&[?|?])]; simpl; eauto.
      + destruct (pcore x) as [cx|] eqn:?; eauto.
        destruct (cmra_pcore_mono x y cx) as (?&?&?); eauto 10.
      + destruct (pcore x) as [cx|] eqn:?; eauto.
        destruct (cmra_pcore_proper x y cx) as (?&?&?); eauto 10.
    - by apply option_distrib.
    - intros n [x|] [y|]; rewrite /validN /option_validN /=;
        eauto using cmra_validN_op_l.
    - intros n mx my1 my2.
      destruct mx as [x|], my1 as [y1|], my2 as [y2|]; intros Hx Hx';
        try (by exfalso; inversion Hx'; auto).
      + destruct (cmra_extend n x y1 y2) as ([z1 z2]&?&?&?); auto.
        { by inversion_clear Hx'. }
        by (Some z1, Some z2); repeat constructor.
      + by (Some x,None); inversion Hx'; repeat constructor.
      + by (None,Some x); inversion Hx'; repeat constructor.
      + (None,None); repeat constructor.
  Qed.
  Canonical Structure optionR :=
    CMRAT (option A) option_cofe_mixin option_cmra_mixin.

  Global Instance option_cmra_discrete : CMRADiscrete A CMRADiscrete optionR.
  Proof. split; [apply _|]. by intros [x|]; [apply (cmra_discrete_valid x)|]. Qed.

  Instance option_empty : Empty (option A) := None.
  Lemma option_ucmra_mixin : UCMRAMixin optionR.
  Proof. split. done. by intros []. by inversion_clear 1. done. Qed.
  Canonical Structure optionUR :=
    UCMRAT (option A) option_cofe_mixin option_cmra_mixin option_ucmra_mixin.

Misc
  Global Instance Some_cmra_monotone : CMRAMonotone Some.
  Proof. split; [apply _|done|intros x y [z ->]; by (Some z)]. Qed.

  Lemma op_None mx my : mx my = None mx = None my = None.
  Proof. destruct mx, my; naive_solver. Qed.
  Lemma op_is_Some mx my : is_Some (mx my) is_Some mx is_Some my.
  Proof. rewrite -!not_eq_None_Some op_None. destruct mx, my; naive_solver. Qed.

  Global Instance Some_persistent (x : A) : Persistent x Persistent (Some x).
  Proof. by constructor. Qed.
  Global Instance option_persistent (mx : option A) :
    ( x : A, Persistent x) Persistent mx.
  Proof. intros. destruct mx; apply _. Qed.

  Lemma exclusiveN_Some_l n x `{!Exclusive x} my :
    ✓{n} (Some x my) my = None.
  Proof. destruct my. move⇒ /(exclusiveN_l _ x) []. done. Qed.
  Lemma exclusiveN_Some_r n x `{!Exclusive x} my :
    ✓{n} (my Some x) my = None.
  Proof. rewrite comm. by apply exclusiveN_Some_l. Qed.
End option.

Arguments optionR : clear implicits.
Arguments optionUR : clear implicits.

Instance option_fmap_cmra_monotone {A B : cmraT} (f: A B) `{!CMRAMonotone f} :
  CMRAMonotone (fmap f : option A option B).
Proof.
  split; first apply _.
  - intros n [x|] ?; rewrite /cmra_validN //=. by apply (validN_preserving f).
  - intros mx my; rewrite !option_included.
    intros [->|(x&y&->&->&[?|Hxy])]; simpl; eauto 10 using @cmra_monotone.
    right; (f x), (f y). by rewrite {4}Hxy; eauto.
Qed.
Program Definition optionURF (F : rFunctor) : urFunctor := {|
  urFunctor_car A B := optionUR (rFunctor_car F A B);
  urFunctor_map A1 A2 B1 B2 fg := optionC_map (rFunctor_map F fg)
|}.
Next Obligation.
  by intros F A1 A2 B1 B2 n f g Hfg; apply optionC_map_ne, rFunctor_ne.
Qed.
Next Obligation.
  intros F A B x. rewrite /= -{2}(option_fmap_id x).
  apply option_fmap_setoid_exty; apply rFunctor_id.
Qed.
Next Obligation.
  intros F A1 A2 A3 B1 B2 B3 f g f' g' x. rewrite /= -option_fmap_compose.
  apply option_fmap_setoid_exty; apply rFunctor_compose.
Qed.

Instance optionURF_contractive F :
  rFunctorContractive F urFunctorContractive (optionURF F).
Proof.
  by intros ? A1 A2 B1 B2 n f g Hfg; apply optionC_map_ne, rFunctor_contractive.
Qed.