diff --git a/theories/list.v b/theories/list.v index ccfdef77c4b32a5a1f711e62722f901ad9d75eef..c00e8dc1ae8367b737247b734293a16e104310c5 100644 --- a/theories/list.v +++ b/theories/list.v @@ -2746,6 +2746,26 @@ Proof. rewrite <-(elem_of_nil x). apply Hl, elem_of_cons. by left. Qed. +Lemma list_subseteq_skip x l1 l2 : l1 ⊆ l2 → x :: l1 ⊆ x :: l2. +Proof. + intros Hin y Hy%elem_of_cons. + destruct Hy as [-> | Hy]; [by left|]. right. by apply Hin. +Qed. +Lemma list_subseteq_cons x l1 l2 : l1 ⊆ l2 → l1 ⊆ x :: l2. +Proof. intros Hin y Hy. right. by apply Hin. Qed. +Lemma list_delete_subseteq i l : delete i l ⊆ l. +Proof. + revert i. induction l as [|x l IHl]; intros i; [done|]. + destruct i as [|i]; + [by apply list_subseteq_cons|by apply list_subseteq_skip]. +Qed. +Lemma list_filter_subseteq P `{!∀ x : A, Decision (P x)} l : + filter P l ⊆ l. +Proof. + induction l as [|x l IHl]; [done|]. rewrite filter_cons. + destruct (decide (P x)); + [by apply list_subseteq_skip|by apply list_subseteq_cons]. +Qed. Global Instance list_subseteq_Permutation: Proper ((≡ₚ) ==> (≡ₚ) ==> (↔)) (⊆@{list A}) . Proof. intros l1 l2 Hl k1 k2 Hk. apply forall_proper; intros x. by rewrite Hl, Hk. Qed.