From prelude Require Export sets. From algebra Require Export cmra. From algebra Require Import dra. Local Arguments valid _ _ !_ /. Local Arguments op _ _ !_ !_ /. Local Arguments unit _ _ !_ /. Module sts. Record Sts := { state : Type; token : Type; trans : relation state; tok : state → set token; }. (* The type of bounds we can give to the state of an STS. This is the type that we equip with an RA structure. *) Inductive bound (sts : Sts) := | bound_auth : state sts → set (token sts) → bound sts | bound_frag : set (state sts) → set (token sts )→ bound sts. Arguments bound_auth {_} _ _. Arguments bound_frag {_} _ _. Section sts_core. Context (sts : Sts). Infix "≼" := dra_included. Notation state := (state sts). Notation token := (token sts). Notation trans := (trans sts). Notation tok := (tok sts). Inductive equiv : Equiv (bound sts) := | auth_equiv s T1 T2 : T1 ≡ T2 → bound_auth s T1 ≡ bound_auth s T2 | frag_equiv S1 S2 T1 T2 : T1 ≡ T2 → S1 ≡ S2 → bound_frag S1 T1 ≡ bound_frag S2 T2. Global Existing Instance equiv. Inductive step : relation (state * set token) := | Step s1 s2 T1 T2 : trans s1 s2 → tok s1 ∩ T1 ≡ ∅ → tok s2 ∩ T2 ≡ ∅ → tok s1 ∪ T1 ≡ tok s2 ∪ T2 → step (s1,T1) (s2,T2). Hint Resolve Step. Inductive frame_step (T : set token) (s1 s2 : state) : Prop := | Frame_step T1 T2 : T1 ∩ (tok s1 ∪ T) ≡ ∅ → step (s1,T1) (s2,T2) → frame_step T s1 s2. Hint Resolve Frame_step. Record closed (S : set state) (T : set token) : Prop := Closed { closed_ne : S ≢ ∅; closed_disjoint s : s ∈ S → tok s ∩ T ≡ ∅; closed_step s1 s2 : s1 ∈ S → frame_step T s1 s2 → s2 ∈ S }. Lemma closed_steps S T s1 s2 : closed S T → s1 ∈ S → rtc (frame_step T) s1 s2 → s2 ∈ S. Proof. induction 3; eauto using closed_step. Qed. Global Instance valid : Valid (bound sts) := λ x, match x with | bound_auth s T => tok s ∩ T ≡ ∅ | bound_frag S' T => closed S' T end. Definition up (s : state) (T : set token) : set state := mkSet (rtc (frame_step T) s). Definition up_set (S : set state) (T : set token) : set state := S ≫= λ s, up s T. Global Instance unit : Unit (bound sts) := λ x, match x with | bound_frag S' _ => bound_frag (up_set S' ∅ ) ∅ | bound_auth s _ => bound_frag (up s ∅) ∅ end. Inductive disjoint : Disjoint (bound sts) := | frag_frag_disjoint S1 S2 T1 T2 : S1 ∩ S2 ≢ ∅ → T1 ∩ T2 ≡ ∅ → bound_frag S1 T1 ⊥ bound_frag S2 T2 | auth_frag_disjoint s S T1 T2 : s ∈ S → T1 ∩ T2 ≡ ∅ → bound_auth s T1 ⊥ bound_frag S T2 | frag_auth_disjoint s S T1 T2 : s ∈ S → T1 ∩ T2 ≡ ∅ → bound_frag S T1 ⊥ bound_auth s T2. Global Existing Instance disjoint. Global Instance op : Op (bound sts) := λ x1 x2, match x1, x2 with | bound_frag S1 T1, bound_frag S2 T2 => bound_frag (S1 ∩ S2) (T1 ∪ T2) | bound_auth s T1, bound_frag _ T2 => bound_auth s (T1 ∪ T2) | bound_frag _ T1, bound_auth s T2 => bound_auth s (T1 ∪ T2) | bound_auth s T1, bound_auth _ T2 => bound_auth s (T1 ∪ T2)(* never happens *) end. Global Instance minus : Minus (bound sts) := λ x1 x2, match x1, x2 with | bound_frag S1 T1, bound_frag S2 T2 => bound_frag (up_set S1 (T1 ∖ T2)) (T1 ∖ T2) | bound_auth s T1, bound_frag _ T2 => bound_auth s (T1 ∖ T2) | bound_frag _ T2, bound_auth s T1 => bound_auth s (T1 ∖ T2) (* never happens *) | bound_auth s T1, bound_auth _ T2 => bound_frag (up s (T1 ∖ T2)) (T1 ∖ T2) end. Hint Extern 10 (base.equiv (A:=set _) _ _) => solve_elem_of : sts. Hint Extern 10 (¬(base.equiv (A:=set _) _ _)) => solve_elem_of : sts. Hint Extern 10 (_ ∈ _) => solve_elem_of : sts. Hint Extern 10 (_ ⊆ _) => solve_elem_of : sts. Instance: Equivalence ((≡) : relation (bound sts)). Proof. split. * by intros []; constructor. * by destruct 1; constructor. * destruct 1; inversion_clear 1; constructor; etransitivity; eauto. Qed. Instance framestep_proper : Proper ((≡) ==> (=) ==> (=) ==> impl) frame_step. Proof. intros ?? HT ?? <- ?? <-; destruct 1; econstructor; eauto with sts. Qed. Instance closed_proper' : Proper ((≡) ==> (≡) ==> impl) closed. Proof. intros ?? HT ?? HS; destruct 1; constructor; intros until 0; rewrite -?HS -?HT; eauto. Qed. Instance closed_proper : Proper ((≡) ==> (≡) ==> iff) closed. Proof. by split; apply closed_proper'. Qed. Lemma closed_op T1 T2 S1 S2 : closed S1 T1 → closed S2 T2 → T1 ∩ T2 ≡ ∅ → S1 ∩ S2 ≢ ∅ → closed (S1 ∩ S2) (T1 ∪ T2). Proof. intros [_ ? Hstep1] [_ ? Hstep2] ?; split; [done|solve_elem_of|]. intros s3 s4; rewrite !elem_of_intersection; intros [??] [T3 T4 ?]; split. * apply Hstep1 with s3, Frame_step with T3 T4; auto with sts. * apply Hstep2 with s3, Frame_step with T3 T4; auto with sts. Qed. Instance up_preserving : Proper ((=) ==> flip (⊆) ==> (⊆)) up. Proof. intros s ? <- T T' HT ; apply elem_of_subseteq. induction 1 as [|s1 s2 s3 [T1 T2]]; [constructor|]. eapply rtc_l; [eapply Frame_step with T1 T2|]; eauto with sts. Qed. Instance up_proper : Proper ((=) ==> (≡) ==> (≡)) up. Proof. by intros ??? ?? [??]; split; apply up_preserving. Qed. Instance up_set_preserving : Proper ((⊆) ==> flip (⊆) ==> (⊆)) up_set. Proof. intros S1 S2 HS T1 T2 HT. rewrite /up_set. f_equiv; last done. move =>s1 s2 Hs. simpl in HT. by apply up_preserving. Qed. Instance up_set_proper : Proper ((≡) ==> (≡) ==> (≡)) up_set. Proof. by intros ?? EQ1 ?? EQ2; split; apply up_set_preserving; rewrite ?EQ1 ?EQ2. Qed. Lemma elem_of_up s T : s ∈ up s T. Proof. constructor. Qed. Lemma subseteq_up_set S T : S ⊆ up_set S T. Proof. intros s ?; apply elem_of_bind; eauto using elem_of_up. Qed. Lemma up_up_set s T : up s T ≡ up_set {[ s ]} T. Proof. by rewrite /up_set collection_bind_singleton. Qed. Lemma closed_up_set S T : (∀ s, s ∈ S → tok s ∩ T ≡ ∅) → S ≢ ∅ → closed (up_set S T) T. Proof. intros HS Hne; unfold up_set; split. * assert (∀ s, s ∈ up s T) by eauto using elem_of_up. solve_elem_of. * intros s; rewrite !elem_of_bind; intros (s'&Hstep&Hs'). specialize (HS s' Hs'); clear Hs' Hne S. induction Hstep as [s|s1 s2 s3 [T1 T2 ? Hstep] ? IH]; auto. inversion_clear Hstep; apply IH; clear IH; auto with sts. * intros s1 s2; rewrite !elem_of_bind; intros (s&?&?) ?; exists s. split; [eapply rtc_r|]; eauto. Qed. Lemma closed_up_set_empty S : S ≢ ∅ → closed (up_set S ∅) ∅. Proof. eauto using closed_up_set with sts. Qed. Lemma closed_up s T : tok s ∩ T ≡ ∅ → closed (up s T) T. Proof. intros; rewrite -(collection_bind_singleton (λ s, up s T) s). apply closed_up_set; solve_elem_of. Qed. Lemma closed_up_empty s : closed (up s ∅) ∅. Proof. eauto using closed_up with sts. Qed. Lemma up_closed S T : closed S T → up_set S T ≡ S. Proof. intros; split; auto using subseteq_up_set; intros s. unfold up_set; rewrite elem_of_bind; intros (s'&Hstep&?). induction Hstep; eauto using closed_step. Qed. Global Instance dra : DRA (bound sts). Proof. split. * apply _. * by do 2 destruct 1; constructor; setoid_subst. * by destruct 1; constructor; setoid_subst. * by intros ? [|]; destruct 1; inversion_clear 1; constructor; setoid_subst. * by do 2 destruct 1; constructor; setoid_subst. * assert (∀ T T' S s, closed S T → s ∈ S → tok s ∩ T' ≡ ∅ → tok s ∩ (T ∪ T') ≡ ∅). { intros S T T' s [??]; solve_elem_of. } destruct 3; simpl in *; auto using closed_op with sts. * intros []; simpl; eauto using closed_up, closed_up_set, closed_ne with sts. * intros ???? (z&Hy&?&Hxz); destruct Hxz; inversion Hy;clear Hy; setoid_subst; rewrite ?disjoint_union_difference; auto using closed_up with sts. eapply closed_up_set; eauto 2 using closed_disjoint with sts. * intros [] [] []; constructor; rewrite ?assoc; auto with sts. * destruct 4; inversion_clear 1; constructor; auto with sts. * destruct 4; inversion_clear 1; constructor; auto with sts. * destruct 1; constructor; auto with sts. * destruct 3; constructor; auto with sts. * intros [|S T]; constructor; auto using elem_of_up with sts. assert (S ⊆ up_set S ∅ ∧ S ≢ ∅) by eauto using subseteq_up_set, closed_ne. solve_elem_of. * intros [|S T]; constructor; auto with sts. assert (S ⊆ up_set S ∅); auto using subseteq_up_set with sts. * intros [s T|S T]; constructor; auto with sts. + rewrite (up_closed (up _ _)); auto using closed_up with sts. + rewrite (up_closed (up_set _ _)); eauto using closed_up_set, closed_ne with sts. * intros x y ?? (z&Hy&?&Hxz); exists (unit (x ⋅ y)); split_ands. + destruct Hxz;inversion_clear Hy;constructor;unfold up_set; solve_elem_of. + destruct Hxz; inversion_clear Hy; simpl; auto using closed_up_set_empty, closed_up_empty with sts. + destruct Hxz; inversion_clear Hy; constructor; repeat match goal with | |- context [ up_set ?S ?T ] => unless (S ⊆ up_set S T) by done; pose proof (subseteq_up_set S T) | |- context [ up ?s ?T ] => unless (s ∈ up s T) by done; pose proof (elem_of_up s T) end; auto with sts. * intros x y ?? (z&Hy&_&Hxz); destruct Hxz; inversion_clear Hy; constructor; repeat match goal with | |- context [ up_set ?S ?T ] => unless (S ⊆ up_set S T) by done; pose proof (subseteq_up_set S T) | |- context [ up ?s ?T ] => unless (s ∈ up s T) by done; pose proof (elem_of_up s T) end; auto with sts. * intros x y ?? (z&Hy&?&Hxz); destruct Hxz as [S1 S2 T1 T2| |]; inversion Hy; clear Hy; constructor; setoid_subst; rewrite ?disjoint_union_difference; auto. split; [|apply intersection_greatest; auto using subseteq_up_set with sts]. apply intersection_greatest; [auto with sts|]. intros s2; rewrite elem_of_intersection. unfold up_set; rewrite elem_of_bind; intros (?&s1&?&?&?). apply closed_steps with T2 s1; auto with sts. Qed. Lemma step_closed s1 s2 T1 T2 S Tf : step (s1,T1) (s2,T2) → closed S Tf → s1 ∈ S → T1 ∩ Tf ≡ ∅ → s2 ∈ S ∧ T2 ∩ Tf ≡ ∅ ∧ tok s2 ∩ T2 ≡ ∅. Proof. inversion_clear 1 as [???? HR Hs1 Hs2]; intros [?? Hstep]??; split_ands; auto. * eapply Hstep with s1, Frame_step with T1 T2; auto with sts. * solve_elem_of -Hstep Hs1 Hs2. Qed. End sts_core. Section stsRA. Context (sts : Sts). Canonical Structure RA := validityRA (bound sts). Definition auth (s : state sts) (T : set (token sts)) : RA := to_validity (bound_auth s T). Definition frag (S : set (state sts)) (T : set (token sts)) : RA := to_validity (bound_frag S T). Lemma update_auth s1 s2 T1 T2 : step sts (s1,T1) (s2,T2) → auth s1 T1 ~~> auth s2 T2. Proof. intros ?; apply validity_update; inversion 3 as [|? S ? Tf|]; subst. destruct (step_closed sts s1 s2 T1 T2 S Tf) as (?&?&?); auto. repeat (done || constructor). Qed. Lemma sts_update_frag S1 S2 (T : set (token sts)) : S1 ⊆ S2 → closed sts S2 T → frag S1 T ~~> frag S2 T. Proof. move=>HS Hcl. eapply validity_update; inversion 3 as [|? S ? Tf|]; subst. - split; first done. constructor; last done. solve_elem_of. - split; first done. constructor; solve_elem_of. Qed. Lemma frag_included S1 S2 T1 T2 : closed sts S2 T2 → frag S1 T1 ≼ frag S2 T2 ↔ (closed sts S1 T1 ∧ ∃ Tf, T2 ≡ T1 ∪ Tf ∧ T1 ∩ Tf ≡ ∅ ∧ S2 ≡ (S1 ∩ up_set sts S2 Tf)). Proof. move=>Hcl2. split. - intros [xf EQ]. destruct xf as [xf vf Hvf]. destruct xf as [Sf Tf|Sf Tf]. { exfalso. inversion_clear EQ as [Hv EQ']. apply EQ' in Hcl2. simpl in Hcl2. inversion Hcl2. } inversion_clear EQ as [Hv EQ']. move:(EQ' Hcl2)=>{EQ'} EQ. inversion_clear EQ as [|? ? ? ? HT HS]. destruct Hv as [Hv _]. move:(Hv Hcl2)=>{Hv} [/= Hcl1 [Hclf Hdisj]]. apply Hvf in Hclf. simpl in Hclf. clear Hvf. inversion_clear Hdisj. split; last (exists Tf; split_ands); [done..|]. apply (anti_symm (⊆)). + move=>s HS2. apply elem_of_intersection. split; first by apply HS. by apply sts.subseteq_up_set. + move=>s /elem_of_intersection [HS1 Hscl]. apply HS. split; first done. destruct Hscl as [s' [Hsup Hs']]. eapply sts.closed_steps; last (hnf in Hsup; eexact Hsup); first done. solve_elem_of +HS Hs'. - intros (Hcl1 & Tf & Htk & Hf & Hs). exists (frag (up_set sts S2 Tf) Tf). split; first split; simpl;[|done|]. + intros _. split_ands; first done. * apply sts.closed_up_set; last by eapply sts.closed_ne. move=>s Hs2. move:(closed_disjoint sts _ _ Hcl2 _ Hs2). solve_elem_of +Htk. * constructor; last done. rewrite -Hs. by eapply sts.closed_ne. + intros _. constructor; [ solve_elem_of +Htk | done]. Qed. Lemma frag_included' S1 S2 T : closed sts S2 T → closed sts S1 T → S2 ≡ (S1 ∩ sts.up_set sts S2 ∅) → frag S1 T ≼ frag S2 T. Proof. intros. apply frag_included; first done. split; first done. exists ∅. split_ands; done || solve_elem_of+. Qed. End stsRA. End sts.