Commit 40e98b1b by Robbert Krebbers

### More generic definition of minimal that also for for anti-symmetric relations.

parent 32abe0c0
 ... ... @@ -996,7 +996,7 @@ End seq_set. (** Mimimal elements *) Definition minimal `{ElemOf A C} (R : relation A) (x : A) (X : C) : Prop := ∀ y, y ∈ X → R y x → y = x. ∀ y, y ∈ X → R y x → R x y. Instance: Params (@minimal) 5. Section minimal. ... ... @@ -1004,6 +1004,20 @@ Section minimal. Global Instance minimal_proper x : Proper (@equiv C _ ==> iff) (minimal R x). Proof. intros X X' y; unfold minimal; set_solver. Qed. Lemma minimal_anti_symm `{!AntiSymm (=) R} x X : minimal R x X ↔ ∀ y, y ∈ X → R y x → x = y. Proof. unfold minimal; split; [|naive_solver]. intros Hmin y ??. apply (anti_symm _); auto. Qed. Lemma minimal_strict `{!StrictOrder R} x X : minimal R x X ↔ ∀ y, y ∈ X → ¬R y x. Proof. unfold minimal; split; [|naive_solver]. intros Hmin y ??. destruct (irreflexivity R x); trans y; auto. Qed. Lemma empty_minimal x : minimal R x ∅. Proof. unfold minimal; set_solver. Qed. Lemma singleton_minimal x : minimal R x {[ x ]}. ... ... @@ -1016,11 +1030,10 @@ Section minimal. Lemma minimal_subseteq X Y x : minimal R x X → Y ⊆ X → minimal R x Y. Proof. unfold minimal; set_solver. Qed. Lemma minimal_weaken `{!StrictOrder R} X x x' : Lemma minimal_weaken `{!Transitive R} X x x' : minimal R x X → R x' x → minimal R x' X. Proof. intros Hmin ? y ??. assert (y = x) as -> by (apply (Hmin y); [done|by trans x']). destruct (irreflexivity R x). by trans x'. intros Hmin ? y ??. trans x; [done|]. by eapply (Hmin y), transitivity. Qed. End minimal.
 ... ... @@ -189,7 +189,7 @@ Lemma collection_fold_proper {B} (R : relation B) `{!Equivalence R} Proof. intros ?? E. apply (foldr_permutation R f b); auto. by rewrite E. Qed. (** * Minimal elements *) Lemma minimal_exists `{!StrictOrder R, ∀ x y, Decision (R x y)} (X : C) : Lemma minimal_exists R `{!Transitive R, ∀ x y, Decision (R x y)} (X : C) : X ≢ ∅ → ∃ x, x ∈ X ∧ minimal R x X. Proof. pattern X; apply collection_ind; clear X. ... ... @@ -205,10 +205,10 @@ Proof. exists x; split; [set_solver|]. rewrite HX, (right_id _ (∪)). apply singleton_minimal. Qed. Lemma minimal_exists_L `{!LeibnizEquiv C, !StrictOrder R, ∀ x y, Decision (R x y)} (X : C) : Lemma minimal_exists_L R `{!LeibnizEquiv C, !Transitive R, ∀ x y, Decision (R x y)} (X : C) : X ≠ ∅ → ∃ x, x ∈ X ∧ minimal R x X. Proof. unfold_leibniz. apply minimal_exists. Qed. Proof. unfold_leibniz. apply (minimal_exists R). Qed. (** * Filter *) Lemma elem_of_filter (P : A → Prop) `{!∀ x, Decision (P x)} X x : ... ...
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