Library stdpp.list_monad
From Coq Require Export Permutation.
From stdpp Require Export numbers base option list_basics list_relations.
From stdpp Require Import options.
From stdpp Require Export numbers base option list_basics list_relations.
From stdpp Require Import options.
The monadic operations.
Global Instance list_ret: MRet list := λ A x, x :: @nil A.
Global Instance list_fmap : FMap list := λ A B f,
fix go (l : list A) := match l with [] ⇒ [] | x :: l ⇒ f x :: go l end.
Global Instance list_omap : OMap list := λ A B f,
fix go (l : list A) :=
match l with
| [] ⇒ []
| x :: l ⇒ match f x with Some y ⇒ y :: go l | None ⇒ go l end
end.
Global Instance list_bind : MBind list := λ A B f,
fix go (l : list A) := match l with [] ⇒ [] | x :: l ⇒ f x ++ go l end.
Global Instance list_join: MJoin list :=
fix go A (ls : list (list A)) : list A :=
match ls with [] ⇒ [] | l :: ls ⇒ l ++ @mjoin _ go _ ls end.
Definition mapM `{MBind M, MRet M} {A B} (f : A → M B) : list A → M (list B) :=
fix go l :=
match l with [] ⇒ mret [] | x :: l ⇒ y ← f x; k ← go l; mret (y :: k) end.
Global Instance: Params (@mapM) 5 := {}.
Global Instance list_fmap : FMap list := λ A B f,
fix go (l : list A) := match l with [] ⇒ [] | x :: l ⇒ f x :: go l end.
Global Instance list_omap : OMap list := λ A B f,
fix go (l : list A) :=
match l with
| [] ⇒ []
| x :: l ⇒ match f x with Some y ⇒ y :: go l | None ⇒ go l end
end.
Global Instance list_bind : MBind list := λ A B f,
fix go (l : list A) := match l with [] ⇒ [] | x :: l ⇒ f x ++ go l end.
Global Instance list_join: MJoin list :=
fix go A (ls : list (list A)) : list A :=
match ls with [] ⇒ [] | l :: ls ⇒ l ++ @mjoin _ go _ ls end.
Definition mapM `{MBind M, MRet M} {A B} (f : A → M B) : list A → M (list B) :=
fix go l :=
match l with [] ⇒ mret [] | x :: l ⇒ y ← f x; k ← go l; mret (y :: k) end.
Global Instance: Params (@mapM) 5 := {}.
We define stronger variants of the map function that allow the mapped
function to use the index of the elements.
Fixpoint imap {A B} (f : nat → A → B) (l : list A) : list B :=
match l with
| [] ⇒ []
| x :: l ⇒ f 0 x :: imap (f ∘ S) l
end.
Global Instance: Params (@imap) 2 := {}.
Definition zipped_map {A B} (f : list A → list A → A → B) :
list A → list A → list B := fix go l k :=
match k with
| [] ⇒ []
| x :: k ⇒ f l k x :: go (x :: l) k
end.
Global Instance: Params (@zipped_map) 2 := {}.
Fixpoint imap2 {A B C} (f : nat → A → B → C) (l : list A) (k : list B) : list C :=
match l, k with
| [], _ | _, [] ⇒ []
| x :: l, y :: k ⇒ f 0 x y :: imap2 (f ∘ S) l k
end.
Global Instance: Params (@imap2) 3 := {}.
Inductive zipped_Forall {A} (P : list A → list A → A → Prop) :
list A → list A → Prop :=
| zipped_Forall_nil l : zipped_Forall P l []
| zipped_Forall_cons l k x :
P l k x → zipped_Forall P (x :: l) k → zipped_Forall P l (x :: k).
Global Arguments zipped_Forall_nil {_ _} _ : assert.
Global Arguments zipped_Forall_cons {_ _} _ _ _ _ _ : assert.
match l with
| [] ⇒ []
| x :: l ⇒ f 0 x :: imap (f ∘ S) l
end.
Global Instance: Params (@imap) 2 := {}.
Definition zipped_map {A B} (f : list A → list A → A → B) :
list A → list A → list B := fix go l k :=
match k with
| [] ⇒ []
| x :: k ⇒ f l k x :: go (x :: l) k
end.
Global Instance: Params (@zipped_map) 2 := {}.
Fixpoint imap2 {A B C} (f : nat → A → B → C) (l : list A) (k : list B) : list C :=
match l, k with
| [], _ | _, [] ⇒ []
| x :: l, y :: k ⇒ f 0 x y :: imap2 (f ∘ S) l k
end.
Global Instance: Params (@imap2) 3 := {}.
Inductive zipped_Forall {A} (P : list A → list A → A → Prop) :
list A → list A → Prop :=
| zipped_Forall_nil l : zipped_Forall P l []
| zipped_Forall_cons l k x :
P l k x → zipped_Forall P (x :: l) k → zipped_Forall P l (x :: k).
Global Arguments zipped_Forall_nil {_ _} _ : assert.
Global Arguments zipped_Forall_cons {_ _} _ _ _ _ _ : assert.
The Cartesian product on lists satisfies (lemma elem_of_list_cprod):
x ∈ cprod l k ↔ x.1 ∈ l ∧ x.2 ∈ k
There are little meaningful things to say about the order of the elements in
cprod (so there are no lemmas for that). It thus only makes sense to use
cprod when treating the lists as a set-like structure (i.e., up to duplicates
and permutations).
Global Instance list_cprod {A B} : CProd (list A) (list B) (list (A × B)) :=
λ l k, x ← l; (x,.) <$> k.
λ l k, x ← l; (x,.) <$> k.
Fixpoint interleave {A} (x : A) (l : list A) : list (list A) :=
match l with
| [] ⇒ [[x]]| y :: l ⇒ (x :: y :: l) :: ((y ::.) <$> interleave x l)
end.
Fixpoint permutations {A} (l : list A) : list (list A) :=
match l with [] ⇒ [[]] | x :: l ⇒ permutations l ≫= interleave x end.
Section general_properties.
Context {A : Type}.
Implicit Types x y z : A.
Implicit Types l k : list A.
match l with
| [] ⇒ [[x]]| y :: l ⇒ (x :: y :: l) :: ((y ::.) <$> interleave x l)
end.
Fixpoint permutations {A} (l : list A) : list (list A) :=
match l with [] ⇒ [[]] | x :: l ⇒ permutations l ≫= interleave x end.
Section general_properties.
Context {A : Type}.
Implicit Types x y z : A.
Implicit Types l k : list A.
The Cartesian product Correspondence to list_prod from the stdlib, a version that does not use
the CProd class for the interface, nor the monad classes for the definition
Lemma list_cprod_list_prod {B} l (k : list B) : cprod l k = list_prod l k.
Proof. unfold cprod, list_cprod. induction l; f_equal/=; auto. Qed.
Lemma elem_of_list_cprod {B} l (k : list B) (x : A × B) :
x ∈ cprod l k ↔ x.1 ∈ l ∧ x.2 ∈ k.
Proof.
rewrite list_cprod_list_prod, !elem_of_list_In.
destruct x. apply in_prod_iff.
Qed.
End general_properties.
Proof. unfold cprod, list_cprod. induction l; f_equal/=; auto. Qed.
Lemma elem_of_list_cprod {B} l (k : list B) (x : A × B) :
x ∈ cprod l k ↔ x.1 ∈ l ∧ x.2 ∈ k.
Proof.
rewrite list_cprod_list_prod, !elem_of_list_In.
destruct x. apply in_prod_iff.
Qed.
End general_properties.
Lemma list_fmap_id {A} (l : list A) : id <$> l = l.
Proof. induction l; f_equal/=; auto. Qed.
Global Instance list_fmap_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) fmap.
Proof. induction 2; csimpl; constructor; auto. Qed.
Section fmap.
Context {A B : Type} (f : A → B).
Implicit Types l : list A.
Lemma list_fmap_compose {C} (g : B → C) l : g ∘ f <$> l = g <$> (f <$> l).
Proof. induction l; f_equal/=; auto. Qed.
Lemma list_fmap_inj_1 f' l x :
f <$> l = f' <$> l → x ∈ l → f x = f' x.
Proof. intros Hf Hin. induction Hin; naive_solver. Qed.
Definition fmap_nil : f <$> [] = [] := eq_refl.
Definition fmap_cons x l : f <$> x :: l = f x :: (f <$> l) := eq_refl.
Lemma list_fmap_singleton x : f <$> [x] = [f x].
Proof. reflexivity. Qed.
Lemma fmap_app l1 l2 : f <$> l1 ++ l2 = (f <$> l1) ++ (f <$> l2).
Proof. by induction l1; f_equal/=. Qed.
Lemma fmap_snoc l x : f <$> l ++ [x] = (f <$> l) ++ [f x].
Proof. rewrite fmap_app, list_fmap_singleton. done. Qed.
Lemma fmap_nil_inv k : f <$> k = [] → k = [].
Proof. by destruct k. Qed.
Lemma fmap_cons_inv y l k :
f <$> l = y :: k → ∃ x l', y = f x ∧ k = f <$> l' ∧ l = x :: l'.
Proof. intros. destruct l; simplify_eq/=; eauto. Qed.
Lemma fmap_app_inv l k1 k2 :
f <$> l = k1 ++ k2 → ∃ l1 l2, k1 = f <$> l1 ∧ k2 = f <$> l2 ∧ l = l1 ++ l2.
Proof.
revert l. induction k1 as [|y k1 IH]; simpl; [intros l ?; by eexists [],l|].
intros [|x l] ?; simplify_eq/=.
destruct (IH l) as (l1&l2&->&->&->); [done|]. by ∃ (x :: l1), l2.
Qed.
Lemma fmap_option_list mx :
f <$> (option_list mx) = option_list (f <$> mx).
Proof. by destruct mx. Qed.
Lemma list_fmap_alt l :
f <$> l = omap (λ x, Some (f x)) l.
Proof. induction l; simplify_eq/=; done. Qed.
Lemma length_fmap l : length (f <$> l) = length l.
Proof. by induction l; f_equal/=. Qed.
Lemma fmap_reverse l : f <$> reverse l = reverse (f <$> l).
Proof.
induction l as [|?? IH]; csimpl; by rewrite ?reverse_cons, ?fmap_app, ?IH.
Qed.
Lemma fmap_tail l : f <$> tail l = tail (f <$> l).
Proof. by destruct l. Qed.
Lemma fmap_last l : last (f <$> l) = f <$> last l.
Proof. induction l as [|? []]; simpl; auto. Qed.
Lemma fmap_replicate n x : f <$> replicate n x = replicate n (f x).
Proof. by induction n; f_equal/=. Qed.
Lemma fmap_take n l : f <$> take n l = take n (f <$> l).
Proof. revert n. by induction l; intros [|?]; f_equal/=. Qed.
Lemma fmap_drop n l : f <$> drop n l = drop n (f <$> l).
Proof. revert n. by induction l; intros [|?]; f_equal/=. Qed.
Lemma const_fmap (l : list A) (y : B) :
(∀ x, f x = y) → f <$> l = replicate (length l) y.
Proof. intros; induction l; f_equal/=; auto. Qed.
Lemma list_lookup_fmap l i : (f <$> l) !! i = f <$> (l !! i).
Proof. revert i. induction l; intros [|n]; by try revert n. Qed.
Lemma list_lookup_fmap_Some l i x :
(f <$> l) !! i = Some x ↔ ∃ y, l !! i = Some y ∧ x = f y.
Proof. by rewrite list_lookup_fmap, fmap_Some. Qed.
Lemma list_lookup_total_fmap `{!Inhabited A, !Inhabited B} l i :
i < length l → (f <$> l) !!! i = f (l !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, list_lookup_fmap, Hx.
Qed.
Lemma list_lookup_fmap_inv l i x :
(f <$> l) !! i = Some x → ∃ y, x = f y ∧ l !! i = Some y.
Proof.
intros Hi. rewrite list_lookup_fmap in Hi.
destruct (l !! i) eqn:?; simplify_eq/=; eauto.
Qed.
Lemma list_fmap_insert l i x: f <$> <[i:=x]>l = <[i:=f x]>(f <$> l).
Proof. revert i. by induction l; intros [|i]; f_equal/=. Qed.
Lemma list_alter_fmap (g : A → A) (h : B → B) l i :
Forall (λ x, f (g x) = h (f x)) l → f <$> alter g i l = alter h i (f <$> l).
Proof. intros Hl. revert i. by induction Hl; intros [|i]; f_equal/=. Qed.
Lemma list_fmap_delete l i : f <$> (delete i l) = delete i (f <$> l).
Proof.
revert i. induction l; intros i; destruct i; csimpl; eauto.
naive_solver congruence.
Qed.
Lemma elem_of_list_fmap_1 l x : x ∈ l → f x ∈ f <$> l.
Proof. induction 1; csimpl; rewrite elem_of_cons; intuition. Qed.
Lemma elem_of_list_fmap_1_alt l x y : x ∈ l → y = f x → y ∈ f <$> l.
Proof. intros. subst. by apply elem_of_list_fmap_1. Qed.
Lemma elem_of_list_fmap_2 l x : x ∈ f <$> l → ∃ y, x = f y ∧ y ∈ l.
Proof.
induction l as [|y l IH]; simpl; inv 1.
- ∃ y. split; [done | by left].
- destruct IH as [z [??]]; [done|]. ∃ z. split; [done | by right].
Qed.
Lemma elem_of_list_fmap l x : x ∈ f <$> l ↔ ∃ y, x = f y ∧ y ∈ l.
Proof.
naive_solver eauto using elem_of_list_fmap_1_alt, elem_of_list_fmap_2.
Qed.
Lemma elem_of_list_fmap_2_inj `{!Inj (=) (=) f} l x : f x ∈ f <$> l → x ∈ l.
Proof.
intros (y, (E, I))%elem_of_list_fmap_2. by rewrite (inj f) in I.
Qed.
Lemma elem_of_list_fmap_inj `{!Inj (=) (=) f} l x : f x ∈ f <$> l ↔ x ∈ l.
Proof.
naive_solver eauto using elem_of_list_fmap_1, elem_of_list_fmap_2_inj.
Qed.
Lemma list_fmap_inj R1 R2 :
Inj R1 R2 f → Inj (Forall2 R1) (Forall2 R2) (fmap f).
Proof.
intros ? l1. induction l1; intros [|??]; inv 1; constructor; auto.
Qed.
Global Instance list_fmap_eq_inj : Inj (=) (=) f → Inj (=@{list A}) (=) (fmap f).
Proof.
intros ?%list_fmap_inj ?? ?%list_eq_Forall2%(inj _). by apply list_eq_Forall2.
Qed.
Global Instance list_fmap_equiv_inj `{!Equiv A, !Equiv B} :
Inj (≡) (≡) f → Inj (≡@{list A}) (≡) (fmap f).
Proof.
intros ?%list_fmap_inj ?? ?%list_equiv_Forall2%(inj _).
by apply list_equiv_Forall2.
Qed.
Proof. induction l; f_equal/=; auto. Qed.
Global Instance list_fmap_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) fmap.
Proof. induction 2; csimpl; constructor; auto. Qed.
Section fmap.
Context {A B : Type} (f : A → B).
Implicit Types l : list A.
Lemma list_fmap_compose {C} (g : B → C) l : g ∘ f <$> l = g <$> (f <$> l).
Proof. induction l; f_equal/=; auto. Qed.
Lemma list_fmap_inj_1 f' l x :
f <$> l = f' <$> l → x ∈ l → f x = f' x.
Proof. intros Hf Hin. induction Hin; naive_solver. Qed.
Definition fmap_nil : f <$> [] = [] := eq_refl.
Definition fmap_cons x l : f <$> x :: l = f x :: (f <$> l) := eq_refl.
Lemma list_fmap_singleton x : f <$> [x] = [f x].
Proof. reflexivity. Qed.
Lemma fmap_app l1 l2 : f <$> l1 ++ l2 = (f <$> l1) ++ (f <$> l2).
Proof. by induction l1; f_equal/=. Qed.
Lemma fmap_snoc l x : f <$> l ++ [x] = (f <$> l) ++ [f x].
Proof. rewrite fmap_app, list_fmap_singleton. done. Qed.
Lemma fmap_nil_inv k : f <$> k = [] → k = [].
Proof. by destruct k. Qed.
Lemma fmap_cons_inv y l k :
f <$> l = y :: k → ∃ x l', y = f x ∧ k = f <$> l' ∧ l = x :: l'.
Proof. intros. destruct l; simplify_eq/=; eauto. Qed.
Lemma fmap_app_inv l k1 k2 :
f <$> l = k1 ++ k2 → ∃ l1 l2, k1 = f <$> l1 ∧ k2 = f <$> l2 ∧ l = l1 ++ l2.
Proof.
revert l. induction k1 as [|y k1 IH]; simpl; [intros l ?; by eexists [],l|].
intros [|x l] ?; simplify_eq/=.
destruct (IH l) as (l1&l2&->&->&->); [done|]. by ∃ (x :: l1), l2.
Qed.
Lemma fmap_option_list mx :
f <$> (option_list mx) = option_list (f <$> mx).
Proof. by destruct mx. Qed.
Lemma list_fmap_alt l :
f <$> l = omap (λ x, Some (f x)) l.
Proof. induction l; simplify_eq/=; done. Qed.
Lemma length_fmap l : length (f <$> l) = length l.
Proof. by induction l; f_equal/=. Qed.
Lemma fmap_reverse l : f <$> reverse l = reverse (f <$> l).
Proof.
induction l as [|?? IH]; csimpl; by rewrite ?reverse_cons, ?fmap_app, ?IH.
Qed.
Lemma fmap_tail l : f <$> tail l = tail (f <$> l).
Proof. by destruct l. Qed.
Lemma fmap_last l : last (f <$> l) = f <$> last l.
Proof. induction l as [|? []]; simpl; auto. Qed.
Lemma fmap_replicate n x : f <$> replicate n x = replicate n (f x).
Proof. by induction n; f_equal/=. Qed.
Lemma fmap_take n l : f <$> take n l = take n (f <$> l).
Proof. revert n. by induction l; intros [|?]; f_equal/=. Qed.
Lemma fmap_drop n l : f <$> drop n l = drop n (f <$> l).
Proof. revert n. by induction l; intros [|?]; f_equal/=. Qed.
Lemma const_fmap (l : list A) (y : B) :
(∀ x, f x = y) → f <$> l = replicate (length l) y.
Proof. intros; induction l; f_equal/=; auto. Qed.
Lemma list_lookup_fmap l i : (f <$> l) !! i = f <$> (l !! i).
Proof. revert i. induction l; intros [|n]; by try revert n. Qed.
Lemma list_lookup_fmap_Some l i x :
(f <$> l) !! i = Some x ↔ ∃ y, l !! i = Some y ∧ x = f y.
Proof. by rewrite list_lookup_fmap, fmap_Some. Qed.
Lemma list_lookup_total_fmap `{!Inhabited A, !Inhabited B} l i :
i < length l → (f <$> l) !!! i = f (l !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, list_lookup_fmap, Hx.
Qed.
Lemma list_lookup_fmap_inv l i x :
(f <$> l) !! i = Some x → ∃ y, x = f y ∧ l !! i = Some y.
Proof.
intros Hi. rewrite list_lookup_fmap in Hi.
destruct (l !! i) eqn:?; simplify_eq/=; eauto.
Qed.
Lemma list_fmap_insert l i x: f <$> <[i:=x]>l = <[i:=f x]>(f <$> l).
Proof. revert i. by induction l; intros [|i]; f_equal/=. Qed.
Lemma list_alter_fmap (g : A → A) (h : B → B) l i :
Forall (λ x, f (g x) = h (f x)) l → f <$> alter g i l = alter h i (f <$> l).
Proof. intros Hl. revert i. by induction Hl; intros [|i]; f_equal/=. Qed.
Lemma list_fmap_delete l i : f <$> (delete i l) = delete i (f <$> l).
Proof.
revert i. induction l; intros i; destruct i; csimpl; eauto.
naive_solver congruence.
Qed.
Lemma elem_of_list_fmap_1 l x : x ∈ l → f x ∈ f <$> l.
Proof. induction 1; csimpl; rewrite elem_of_cons; intuition. Qed.
Lemma elem_of_list_fmap_1_alt l x y : x ∈ l → y = f x → y ∈ f <$> l.
Proof. intros. subst. by apply elem_of_list_fmap_1. Qed.
Lemma elem_of_list_fmap_2 l x : x ∈ f <$> l → ∃ y, x = f y ∧ y ∈ l.
Proof.
induction l as [|y l IH]; simpl; inv 1.
- ∃ y. split; [done | by left].
- destruct IH as [z [??]]; [done|]. ∃ z. split; [done | by right].
Qed.
Lemma elem_of_list_fmap l x : x ∈ f <$> l ↔ ∃ y, x = f y ∧ y ∈ l.
Proof.
naive_solver eauto using elem_of_list_fmap_1_alt, elem_of_list_fmap_2.
Qed.
Lemma elem_of_list_fmap_2_inj `{!Inj (=) (=) f} l x : f x ∈ f <$> l → x ∈ l.
Proof.
intros (y, (E, I))%elem_of_list_fmap_2. by rewrite (inj f) in I.
Qed.
Lemma elem_of_list_fmap_inj `{!Inj (=) (=) f} l x : f x ∈ f <$> l ↔ x ∈ l.
Proof.
naive_solver eauto using elem_of_list_fmap_1, elem_of_list_fmap_2_inj.
Qed.
Lemma list_fmap_inj R1 R2 :
Inj R1 R2 f → Inj (Forall2 R1) (Forall2 R2) (fmap f).
Proof.
intros ? l1. induction l1; intros [|??]; inv 1; constructor; auto.
Qed.
Global Instance list_fmap_eq_inj : Inj (=) (=) f → Inj (=@{list A}) (=) (fmap f).
Proof.
intros ?%list_fmap_inj ?? ?%list_eq_Forall2%(inj _). by apply list_eq_Forall2.
Qed.
Global Instance list_fmap_equiv_inj `{!Equiv A, !Equiv B} :
Inj (≡) (≡) f → Inj (≡@{list A}) (≡) (fmap f).
Proof.
intros ?%list_fmap_inj ?? ?%list_equiv_Forall2%(inj _).
by apply list_equiv_Forall2.
Qed.
A version of NoDup_fmap_2 that does not require f to be injective for
*all* inputs.
Lemma NoDup_fmap_2_strong l :
(∀ x y, x ∈ l → y ∈ l → f x = f y → x = y) →
NoDup l →
NoDup (f <$> l).
Proof.
intros Hinj. induction 1 as [|x l ?? IH]; simpl; constructor.
- intros [y [Hxy ?]]%elem_of_list_fmap.
apply Hinj in Hxy; [by subst|by constructor..].
- apply IH. clear- Hinj.
intros x' y Hx' Hy. apply Hinj; by constructor.
Qed.
Lemma NoDup_fmap_1 l : NoDup (f <$> l) → NoDup l.
Proof.
induction l; simpl; inv 1; constructor; auto.
rewrite elem_of_list_fmap in ×. naive_solver.
Qed.
Lemma NoDup_fmap_2 `{!Inj (=) (=) f} l : NoDup l → NoDup (f <$> l).
Proof. apply NoDup_fmap_2_strong. intros ?? _ _. apply (inj f). Qed.
Lemma NoDup_fmap `{!Inj (=) (=) f} l : NoDup (f <$> l) ↔ NoDup l.
Proof. split; auto using NoDup_fmap_1, NoDup_fmap_2. Qed.
Global Instance fmap_sublist: Proper (sublist ==> sublist) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Global Instance fmap_submseteq: Proper (submseteq ==> submseteq) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Global Instance fmap_Permutation: Proper ((≡ₚ) ==> (≡ₚ)) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Lemma Forall_fmap_ext_1 (g : A → B) (l : list A) :
Forall (λ x, f x = g x) l → fmap f l = fmap g l.
Proof. by induction 1; f_equal/=. Qed.
Lemma Forall_fmap_ext (g : A → B) (l : list A) :
Forall (λ x, f x = g x) l ↔ fmap f l = fmap g l.
Proof.
split; [auto using Forall_fmap_ext_1|].
induction l; simpl; constructor; simplify_eq; auto.
Qed.
Lemma Forall_fmap (P : B → Prop) l : Forall P (f <$> l) ↔ Forall (P ∘ f) l.
Proof. split; induction l; inv 1; constructor; auto. Qed.
Lemma Exists_fmap (P : B → Prop) l : Exists P (f <$> l) ↔ Exists (P ∘ f) l.
Proof. split; induction l; inv 1; constructor; by auto. Qed.
Lemma Forall2_fmap_l {C} (P : B → C → Prop) l k :
Forall2 P (f <$> l) k ↔ Forall2 (P ∘ f) l k.
Proof.
split; revert k; induction l; inv 1; constructor; auto.
Qed.
Lemma Forall2_fmap_r {C} (P : C → B → Prop) k l :
Forall2 P k (f <$> l) ↔ Forall2 (λ x, P x ∘ f) k l.
Proof.
split; revert k; induction l; inv 1; constructor; auto.
Qed.
Lemma Forall2_fmap_1 {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 P (f <$> l) (g <$> k) → Forall2 (λ x1 x2, P (f x1) (g x2)) l k.
Proof. revert k; induction l; intros [|??]; inv 1; auto. Qed.
Lemma Forall2_fmap_2 {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 (λ x1 x2, P (f x1) (g x2)) l k → Forall2 P (f <$> l) (g <$> k).
Proof. induction 1; csimpl; auto. Qed.
Lemma Forall2_fmap {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 P (f <$> l) (g <$> k) ↔ Forall2 (λ x1 x2, P (f x1) (g x2)) l k.
Proof. split; auto using Forall2_fmap_1, Forall2_fmap_2. Qed.
Lemma list_fmap_bind {C} (g : B → list C) l : (f <$> l) ≫= g = l ≫= g ∘ f.
Proof. by induction l; f_equal/=. Qed.
End fmap.
Section ext.
Context {A B : Type}.
Implicit Types l : list A.
Lemma list_fmap_ext (f g : A → B) l :
(∀ i x, l !! i = Some x → f x = g x) → f <$> l = g <$> l.
Proof.
intros Hfg. apply list_eq; intros i. rewrite !list_lookup_fmap.
destruct (l !! i) eqn:?; f_equal/=; eauto.
Qed.
Lemma list_fmap_equiv_ext `{!Equiv B} (f g : A → B) l :
(∀ i x, l !! i = Some x → f x ≡ g x) → f <$> l ≡ g <$> l.
Proof.
intros Hl. apply list_equiv_lookup; intros i. rewrite !list_lookup_fmap.
destruct (l !! i) eqn:?; simpl; constructor; eauto.
Qed.
End ext.
Lemma list_alter_fmap_mono {A} (f : A → A) (g : A → A) l i :
Forall (λ x, f (g x) = g (f x)) l → f <$> alter g i l = alter g i (f <$> l).
Proof. auto using list_alter_fmap. Qed.
Lemma NoDup_fmap_fst {A B} (l : list (A × B)) :
(∀ x y1 y2, (x,y1) ∈ l → (x,y2) ∈ l → y1 = y2) → NoDup l → NoDup (l.*1).
Proof.
intros Hunique. induction 1 as [|[x1 y1] l Hin Hnodup IH]; csimpl; constructor.
- rewrite elem_of_list_fmap.
intros [[x2 y2] [??]]; simpl in *; subst. destruct Hin.
rewrite (Hunique x2 y1 y2); rewrite ?elem_of_cons; auto.
- apply IH. intros. eapply Hunique; rewrite ?elem_of_cons; eauto.
Qed.
Global Instance list_omap_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) omap.
Proof.
intros f1 f2 Hf. induction 1 as [|x1 x2 l1 l2 Hx Hl]; csimpl; [constructor|].
destruct (Hf _ _ Hx); by repeat f_equiv.
Qed.
Section omap.
Context {A B : Type} (f : A → option B).
Implicit Types l : list A.
Lemma list_fmap_omap {C} (g : B → C) l :
g <$> omap f l = omap (λ x, g <$> (f x)) l.
Proof.
induction l as [|x y IH]; [done|]. csimpl.
destruct (f x); csimpl; [|done]. by f_equal.
Qed.
Lemma list_omap_ext {A'} (g : A' → option B) l1 (l2 : list A') :
Forall2 (λ a b, f a = g b) l1 l2 →
omap f l1 = omap g l2.
Proof.
induction 1 as [|x y l l' Hfg ? IH]; [done|].
csimpl. rewrite Hfg. destruct (g y); [|done]. by f_equal.
Qed.
Lemma elem_of_list_omap l y : y ∈ omap f l ↔ ∃ x, x ∈ l ∧ f x = Some y.
Proof.
split.
- induction l as [|x l]; csimpl; repeat case_match;
repeat (setoid_rewrite elem_of_nil || setoid_rewrite elem_of_cons);
naive_solver.
- intros (x&Hx&?). by induction Hx; csimpl; repeat case_match;
simplify_eq; try constructor; auto.
Qed.
Global Instance omap_Permutation : Proper ((≡ₚ) ==> (≡ₚ)) (omap f).
Proof. induction 1; simpl; repeat case_match; econstructor; eauto. Qed.
Lemma omap_app l1 l2 :
omap f (l1 ++ l2) = omap f l1 ++ omap f l2.
Proof. induction l1; csimpl; repeat case_match; naive_solver congruence. Qed.
Lemma omap_option_list mx :
omap f (option_list mx) = option_list (mx ≫= f).
Proof. by destruct mx. Qed.
End omap.
Global Instance list_bind_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) mbind.
Proof. induction 2; csimpl; constructor || f_equiv; auto. Qed.
Section bind.
Context {A B : Type} (f : A → list B).
Lemma list_bind_ext (g : A → list B) l1 l2 :
(∀ x, f x = g x) → l1 = l2 → l1 ≫= f = l2 ≫= g.
Proof. intros ? <-. by induction l1; f_equal/=. Qed.
Lemma Forall_bind_ext (g : A → list B) (l : list A) :
Forall (λ x, f x = g x) l → l ≫= f = l ≫= g.
Proof. by induction 1; f_equal/=. Qed.
Global Instance bind_sublist: Proper (sublist ==> sublist) (mbind f).
Proof.
induction 1; simpl; auto;
[by apply sublist_app|by apply sublist_inserts_l].
Qed.
Global Instance bind_submseteq: Proper (submseteq ==> submseteq) (mbind f).
Proof.
induction 1; csimpl; auto.
- by apply submseteq_app.
- by rewrite !(assoc_L (++)), (comm (++) (f _)).
- by apply submseteq_inserts_l.
- etrans; eauto.
Qed.
Global Instance bind_Permutation: Proper ((≡ₚ) ==> (≡ₚ)) (mbind f).
Proof.
induction 1; csimpl; auto.
- by f_equiv.
- by rewrite !(assoc_L (++)), (comm (++) (f _)).
- etrans; eauto.
Qed.
Lemma bind_cons x l : (x :: l) ≫= f = f x ++ l ≫= f.
Proof. done. Qed.
Lemma bind_singleton x : [x] ≫= f = f x.
Proof. csimpl. by rewrite (right_id_L _ (++)). Qed.
Lemma bind_app l1 l2 : (l1 ++ l2) ≫= f = (l1 ≫= f) ++ (l2 ≫= f).
Proof. by induction l1; csimpl; rewrite <-?(assoc_L (++)); f_equal. Qed.
Lemma elem_of_list_bind (x : B) (l : list A) :
x ∈ l ≫= f ↔ ∃ y, x ∈ f y ∧ y ∈ l.
Proof.
split.
- induction l as [|y l IH]; csimpl; [inv 1|].
rewrite elem_of_app. intros [?|?].
+ ∃ y. split; [done | by left].
+ destruct IH as [z [??]]; [done|]. ∃ z. split; [done | by right].
- intros [y [Hx Hy]]. induction Hy; csimpl; rewrite elem_of_app; intuition.
Qed.
Lemma Forall_bind (P : B → Prop) l :
Forall P (l ≫= f) ↔ Forall (Forall P ∘ f) l.
Proof.
split.
- induction l; csimpl; rewrite ?Forall_app; constructor; csimpl; intuition.
- induction 1; csimpl; rewrite ?Forall_app; auto.
Qed.
Lemma Forall2_bind {C D} (g : C → list D) (P : B → D → Prop) l1 l2 :
Forall2 (λ x1 x2, Forall2 P (f x1) (g x2)) l1 l2 →
Forall2 P (l1 ≫= f) (l2 ≫= g).
Proof. induction 1; csimpl; auto using Forall2_app. Qed.
Lemma NoDup_bind l :
(∀ x1 x2 y, x1 ∈ l → x2 ∈ l → y ∈ f x1 → y ∈ f x2 → x1 = x2) →
(∀ x, x ∈ l → NoDup (f x)) → NoDup l → NoDup (l ≫= f).
Proof.
intros Hinj Hf. induction 1 as [|x l ?? IH]; csimpl; [constructor|].
apply NoDup_app. split_and!.
- eauto 10 using elem_of_list_here.
- intros y ? (x'&?&?)%elem_of_list_bind.
destruct (Hinj x x' y); auto using elem_of_list_here, elem_of_list_further.
- eauto 10 using elem_of_list_further.
Qed.
End bind.
Global Instance list_join_proper `{!Equiv A} :
Proper ((≡) ==> (≡@{list A})) mjoin.
Proof. induction 1; simpl; [constructor|solve_proper]. Qed.
Section ret_join.
Context {A : Type}.
Lemma list_join_bind (ls : list (list A)) : mjoin ls = ls ≫= id.
Proof. by induction ls; f_equal/=. Qed.
Global Instance join_Permutation : Proper ((≡ₚ@{list A}) ==> (≡ₚ)) mjoin.
Proof. intros ?? E. by rewrite !list_join_bind, E. Qed.
Lemma elem_of_list_ret (x y : A) : x ∈ @mret list _ A y ↔ x = y.
Proof. apply elem_of_list_singleton. Qed.
Lemma elem_of_list_join (x : A) (ls : list (list A)) :
x ∈ mjoin ls ↔ ∃ l : list A, x ∈ l ∧ l ∈ ls.
Proof. by rewrite list_join_bind, elem_of_list_bind. Qed.
Lemma join_nil (ls : list (list A)) : mjoin ls = [] ↔ Forall (.= []) ls.
Proof.
split; [|by induction 1 as [|[|??] ?]].
by induction ls as [|[|??] ?]; constructor; auto.
Qed.
Lemma join_nil_1 (ls : list (list A)) : mjoin ls = [] → Forall (.= []) ls.
Proof. by rewrite join_nil. Qed.
Lemma join_nil_2 (ls : list (list A)) : Forall (.= []) ls → mjoin ls = [].
Proof. by rewrite join_nil. Qed.
Lemma join_app (l1 l2 : list (list A)) :
mjoin (l1 ++ l2) = mjoin l1 ++ mjoin l2.
Proof.
induction l1 as [|x l1 IH]; simpl; [done|]. by rewrite <-(assoc_L _ _), IH.
Qed.
Lemma Forall_join (P : A → Prop) (ls: list (list A)) :
Forall (Forall P) ls → Forall P (mjoin ls).
Proof. induction 1; simpl; auto using Forall_app_2. Qed.
Lemma Forall2_join {B} (P : A → B → Prop) ls1 ls2 :
Forall2 (Forall2 P) ls1 ls2 → Forall2 P (mjoin ls1) (mjoin ls2).
Proof. induction 1; simpl; auto using Forall2_app. Qed.
End ret_join.
Global Instance mapM_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{option (list B)})) mapM.
Proof.
induction 2; csimpl; repeat (f_equiv || constructor || intro || auto).
Qed.
Section mapM.
Context {A B : Type} (f : A → option B).
Lemma mapM_ext (g : A → option B) l : (∀ x, f x = g x) → mapM f l = mapM g l.
Proof. intros Hfg. by induction l as [|?? IHl]; simpl; rewrite ?Hfg, ?IHl. Qed.
Lemma Forall2_mapM_ext (g : A → option B) l k :
Forall2 (λ x y, f x = g y) l k → mapM f l = mapM g k.
Proof. induction 1 as [|???? Hfg ? IH]; simpl; [done|]. by rewrite Hfg, IH. Qed.
Lemma Forall_mapM_ext (g : A → option B) l :
Forall (λ x, f x = g x) l → mapM f l = mapM g l.
Proof. induction 1 as [|?? Hfg ? IH]; simpl; [done|]. by rewrite Hfg, IH. Qed.
Lemma mapM_Some_1 l k : mapM f l = Some k → Forall2 (λ x y, f x = Some y) l k.
Proof.
revert k. induction l as [|x l]; intros [|y k]; simpl; try done.
- destruct (f x); simpl; [|discriminate]. by destruct (mapM f l).
- destruct (f x) eqn:?; intros; simplify_option_eq; auto.
Qed.
Lemma mapM_Some_2 l k : Forall2 (λ x y, f x = Some y) l k → mapM f l = Some k.
Proof.
induction 1 as [|???? Hf ? IH]; simpl; [done |].
rewrite Hf. simpl. by rewrite IH.
Qed.
Lemma mapM_Some l k : mapM f l = Some k ↔ Forall2 (λ x y, f x = Some y) l k.
Proof. split; auto using mapM_Some_1, mapM_Some_2. Qed.
Lemma length_mapM l k : mapM f l = Some k → length l = length k.
Proof. intros. by eapply Forall2_length, mapM_Some_1. Qed.
Lemma mapM_None_1 l : mapM f l = None → Exists (λ x, f x = None) l.
Proof.
induction l as [|x l IH]; simpl; [done|].
destruct (f x) eqn:?; simpl; eauto. by destruct (mapM f l); eauto.
Qed.
Lemma mapM_None_2 l : Exists (λ x, f x = None) l → mapM f l = None.
Proof.
induction 1 as [x l Hx|x l ? IH]; simpl; [by rewrite Hx|].
by destruct (f x); simpl; rewrite ?IH.
Qed.
Lemma mapM_None l : mapM f l = None ↔ Exists (λ x, f x = None) l.
Proof. split; auto using mapM_None_1, mapM_None_2. Qed.
Lemma mapM_is_Some_1 l : is_Some (mapM f l) → Forall (is_Some ∘ f) l.
Proof.
unfold compose. setoid_rewrite <-not_eq_None_Some.
rewrite mapM_None. apply (not_Exists_Forall _).
Qed.
Lemma mapM_is_Some_2 l : Forall (is_Some ∘ f) l → is_Some (mapM f l).
Proof.
unfold compose. setoid_rewrite <-not_eq_None_Some.
rewrite mapM_None. apply (Forall_not_Exists _).
Qed.
Lemma mapM_is_Some l : is_Some (mapM f l) ↔ Forall (is_Some ∘ f) l.
Proof. split; auto using mapM_is_Some_1, mapM_is_Some_2. Qed.
Lemma mapM_fmap_Forall_Some (g : B → A) (l : list B) :
Forall (λ x, f (g x) = Some x) l → mapM f (g <$> l) = Some l.
Proof. by induction 1; simpl; simplify_option_eq. Qed.
Lemma mapM_fmap_Some (g : B → A) (l : list B) :
(∀ x, f (g x) = Some x) → mapM f (g <$> l) = Some l.
Proof. intros. by apply mapM_fmap_Forall_Some, Forall_true. Qed.
Lemma mapM_fmap_Forall2_Some_inv (g : B → A) (l : list A) (k : list B) :
mapM f l = Some k → Forall2 (λ x y, f x = Some y → g y = x) l k → g <$> k = l.
Proof. induction 2; simplify_option_eq; naive_solver. Qed.
Lemma mapM_fmap_Some_inv (g : B → A) (l : list A) (k : list B) :
mapM f l = Some k → (∀ x y, f x = Some y → g y = x) → g <$> k = l.
Proof. eauto using mapM_fmap_Forall2_Some_inv, Forall2_true, length_mapM. Qed.
End mapM.
Lemma imap_const {A B} (f : A → B) l : imap (const f) l = f <$> l.
Proof. induction l; f_equal/=; auto. Qed.
Global Instance imap_proper `{!Equiv A, !Equiv B} :
Proper (pointwise_relation _ ((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B}))
imap.
Proof.
intros f f' Hf l l' Hl. revert f f' Hf.
induction Hl as [|x1 x2 l1 l2 ?? IH]; intros f f' Hf; simpl; constructor.
- by apply Hf.
- apply IH. intros i y y' ?; simpl. by apply Hf.
Qed.
Section imap.
Context {A B : Type} (f : nat → A → B).
Lemma imap_ext g l :
(∀ i x, l !! i = Some x → f i x = g i x) → imap f l = imap g l.
Proof. revert f g; induction l as [|x l IH]; intros; f_equal/=; eauto. Qed.
Lemma imap_nil : imap f [] = [].
Proof. done. Qed.
Lemma imap_app l1 l2 :
imap f (l1 ++ l2) = imap f l1 ++ imap (λ n, f (length l1 + n)) l2.
Proof.
revert f. induction l1 as [|x l1 IH]; intros f; f_equal/=.
by rewrite IH.
Qed.
Lemma imap_cons x l : imap f (x :: l) = f 0 x :: imap (f ∘ S) l.
Proof. done. Qed.
Lemma imap_fmap {C} (g : C → A) l : imap f (g <$> l) = imap (λ n, f n ∘ g) l.
Proof. revert f. induction l; intros; f_equal/=; eauto. Qed.
Lemma fmap_imap {C} (g : B → C) l : g <$> imap f l = imap (λ n, g ∘ f n) l.
Proof. revert f. induction l; intros; f_equal/=; eauto. Qed.
Lemma list_lookup_imap l i : imap f l !! i = f i <$> l !! i.
Proof.
revert f i. induction l as [|x l IH]; intros f [|i]; f_equal/=; auto.
by rewrite IH.
Qed.
Lemma list_lookup_imap_Some l i x :
imap f l !! i = Some x ↔ ∃ y, l !! i = Some y ∧ x = f i y.
Proof. by rewrite list_lookup_imap, fmap_Some. Qed.
Lemma list_lookup_total_imap `{!Inhabited A, !Inhabited B} l i :
i < length l → imap f l !!! i = f i (l !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, list_lookup_imap, Hx.
Qed.
Lemma length_imap l : length (imap f l) = length l.
Proof. revert f. induction l; simpl; eauto. Qed.
Lemma elem_of_lookup_imap_1 l x :
x ∈ imap f l → ∃ i y, x = f i y ∧ l !! i = Some y.
Proof.
intros [i Hin]%elem_of_list_lookup. rewrite list_lookup_imap in Hin.
simplify_option_eq; naive_solver.
Qed.
Lemma elem_of_lookup_imap_2 l x i : l !! i = Some x → f i x ∈ imap f l.
Proof.
intros Hl. rewrite elem_of_list_lookup.
∃ i. by rewrite list_lookup_imap, Hl.
Qed.
Lemma elem_of_lookup_imap l x :
x ∈ imap f l ↔ ∃ i y, x = f i y ∧ l !! i = Some y.
Proof. naive_solver eauto using elem_of_lookup_imap_1, elem_of_lookup_imap_2. Qed.
End imap.
(∀ x y, x ∈ l → y ∈ l → f x = f y → x = y) →
NoDup l →
NoDup (f <$> l).
Proof.
intros Hinj. induction 1 as [|x l ?? IH]; simpl; constructor.
- intros [y [Hxy ?]]%elem_of_list_fmap.
apply Hinj in Hxy; [by subst|by constructor..].
- apply IH. clear- Hinj.
intros x' y Hx' Hy. apply Hinj; by constructor.
Qed.
Lemma NoDup_fmap_1 l : NoDup (f <$> l) → NoDup l.
Proof.
induction l; simpl; inv 1; constructor; auto.
rewrite elem_of_list_fmap in ×. naive_solver.
Qed.
Lemma NoDup_fmap_2 `{!Inj (=) (=) f} l : NoDup l → NoDup (f <$> l).
Proof. apply NoDup_fmap_2_strong. intros ?? _ _. apply (inj f). Qed.
Lemma NoDup_fmap `{!Inj (=) (=) f} l : NoDup (f <$> l) ↔ NoDup l.
Proof. split; auto using NoDup_fmap_1, NoDup_fmap_2. Qed.
Global Instance fmap_sublist: Proper (sublist ==> sublist) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Global Instance fmap_submseteq: Proper (submseteq ==> submseteq) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Global Instance fmap_Permutation: Proper ((≡ₚ) ==> (≡ₚ)) (fmap f).
Proof. induction 1; simpl; econstructor; eauto. Qed.
Lemma Forall_fmap_ext_1 (g : A → B) (l : list A) :
Forall (λ x, f x = g x) l → fmap f l = fmap g l.
Proof. by induction 1; f_equal/=. Qed.
Lemma Forall_fmap_ext (g : A → B) (l : list A) :
Forall (λ x, f x = g x) l ↔ fmap f l = fmap g l.
Proof.
split; [auto using Forall_fmap_ext_1|].
induction l; simpl; constructor; simplify_eq; auto.
Qed.
Lemma Forall_fmap (P : B → Prop) l : Forall P (f <$> l) ↔ Forall (P ∘ f) l.
Proof. split; induction l; inv 1; constructor; auto. Qed.
Lemma Exists_fmap (P : B → Prop) l : Exists P (f <$> l) ↔ Exists (P ∘ f) l.
Proof. split; induction l; inv 1; constructor; by auto. Qed.
Lemma Forall2_fmap_l {C} (P : B → C → Prop) l k :
Forall2 P (f <$> l) k ↔ Forall2 (P ∘ f) l k.
Proof.
split; revert k; induction l; inv 1; constructor; auto.
Qed.
Lemma Forall2_fmap_r {C} (P : C → B → Prop) k l :
Forall2 P k (f <$> l) ↔ Forall2 (λ x, P x ∘ f) k l.
Proof.
split; revert k; induction l; inv 1; constructor; auto.
Qed.
Lemma Forall2_fmap_1 {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 P (f <$> l) (g <$> k) → Forall2 (λ x1 x2, P (f x1) (g x2)) l k.
Proof. revert k; induction l; intros [|??]; inv 1; auto. Qed.
Lemma Forall2_fmap_2 {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 (λ x1 x2, P (f x1) (g x2)) l k → Forall2 P (f <$> l) (g <$> k).
Proof. induction 1; csimpl; auto. Qed.
Lemma Forall2_fmap {C D} (g : C → D) (P : B → D → Prop) l k :
Forall2 P (f <$> l) (g <$> k) ↔ Forall2 (λ x1 x2, P (f x1) (g x2)) l k.
Proof. split; auto using Forall2_fmap_1, Forall2_fmap_2. Qed.
Lemma list_fmap_bind {C} (g : B → list C) l : (f <$> l) ≫= g = l ≫= g ∘ f.
Proof. by induction l; f_equal/=. Qed.
End fmap.
Section ext.
Context {A B : Type}.
Implicit Types l : list A.
Lemma list_fmap_ext (f g : A → B) l :
(∀ i x, l !! i = Some x → f x = g x) → f <$> l = g <$> l.
Proof.
intros Hfg. apply list_eq; intros i. rewrite !list_lookup_fmap.
destruct (l !! i) eqn:?; f_equal/=; eauto.
Qed.
Lemma list_fmap_equiv_ext `{!Equiv B} (f g : A → B) l :
(∀ i x, l !! i = Some x → f x ≡ g x) → f <$> l ≡ g <$> l.
Proof.
intros Hl. apply list_equiv_lookup; intros i. rewrite !list_lookup_fmap.
destruct (l !! i) eqn:?; simpl; constructor; eauto.
Qed.
End ext.
Lemma list_alter_fmap_mono {A} (f : A → A) (g : A → A) l i :
Forall (λ x, f (g x) = g (f x)) l → f <$> alter g i l = alter g i (f <$> l).
Proof. auto using list_alter_fmap. Qed.
Lemma NoDup_fmap_fst {A B} (l : list (A × B)) :
(∀ x y1 y2, (x,y1) ∈ l → (x,y2) ∈ l → y1 = y2) → NoDup l → NoDup (l.*1).
Proof.
intros Hunique. induction 1 as [|[x1 y1] l Hin Hnodup IH]; csimpl; constructor.
- rewrite elem_of_list_fmap.
intros [[x2 y2] [??]]; simpl in *; subst. destruct Hin.
rewrite (Hunique x2 y1 y2); rewrite ?elem_of_cons; auto.
- apply IH. intros. eapply Hunique; rewrite ?elem_of_cons; eauto.
Qed.
Global Instance list_omap_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) omap.
Proof.
intros f1 f2 Hf. induction 1 as [|x1 x2 l1 l2 Hx Hl]; csimpl; [constructor|].
destruct (Hf _ _ Hx); by repeat f_equiv.
Qed.
Section omap.
Context {A B : Type} (f : A → option B).
Implicit Types l : list A.
Lemma list_fmap_omap {C} (g : B → C) l :
g <$> omap f l = omap (λ x, g <$> (f x)) l.
Proof.
induction l as [|x y IH]; [done|]. csimpl.
destruct (f x); csimpl; [|done]. by f_equal.
Qed.
Lemma list_omap_ext {A'} (g : A' → option B) l1 (l2 : list A') :
Forall2 (λ a b, f a = g b) l1 l2 →
omap f l1 = omap g l2.
Proof.
induction 1 as [|x y l l' Hfg ? IH]; [done|].
csimpl. rewrite Hfg. destruct (g y); [|done]. by f_equal.
Qed.
Lemma elem_of_list_omap l y : y ∈ omap f l ↔ ∃ x, x ∈ l ∧ f x = Some y.
Proof.
split.
- induction l as [|x l]; csimpl; repeat case_match;
repeat (setoid_rewrite elem_of_nil || setoid_rewrite elem_of_cons);
naive_solver.
- intros (x&Hx&?). by induction Hx; csimpl; repeat case_match;
simplify_eq; try constructor; auto.
Qed.
Global Instance omap_Permutation : Proper ((≡ₚ) ==> (≡ₚ)) (omap f).
Proof. induction 1; simpl; repeat case_match; econstructor; eauto. Qed.
Lemma omap_app l1 l2 :
omap f (l1 ++ l2) = omap f l1 ++ omap f l2.
Proof. induction l1; csimpl; repeat case_match; naive_solver congruence. Qed.
Lemma omap_option_list mx :
omap f (option_list mx) = option_list (mx ≫= f).
Proof. by destruct mx. Qed.
End omap.
Global Instance list_bind_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B})) mbind.
Proof. induction 2; csimpl; constructor || f_equiv; auto. Qed.
Section bind.
Context {A B : Type} (f : A → list B).
Lemma list_bind_ext (g : A → list B) l1 l2 :
(∀ x, f x = g x) → l1 = l2 → l1 ≫= f = l2 ≫= g.
Proof. intros ? <-. by induction l1; f_equal/=. Qed.
Lemma Forall_bind_ext (g : A → list B) (l : list A) :
Forall (λ x, f x = g x) l → l ≫= f = l ≫= g.
Proof. by induction 1; f_equal/=. Qed.
Global Instance bind_sublist: Proper (sublist ==> sublist) (mbind f).
Proof.
induction 1; simpl; auto;
[by apply sublist_app|by apply sublist_inserts_l].
Qed.
Global Instance bind_submseteq: Proper (submseteq ==> submseteq) (mbind f).
Proof.
induction 1; csimpl; auto.
- by apply submseteq_app.
- by rewrite !(assoc_L (++)), (comm (++) (f _)).
- by apply submseteq_inserts_l.
- etrans; eauto.
Qed.
Global Instance bind_Permutation: Proper ((≡ₚ) ==> (≡ₚ)) (mbind f).
Proof.
induction 1; csimpl; auto.
- by f_equiv.
- by rewrite !(assoc_L (++)), (comm (++) (f _)).
- etrans; eauto.
Qed.
Lemma bind_cons x l : (x :: l) ≫= f = f x ++ l ≫= f.
Proof. done. Qed.
Lemma bind_singleton x : [x] ≫= f = f x.
Proof. csimpl. by rewrite (right_id_L _ (++)). Qed.
Lemma bind_app l1 l2 : (l1 ++ l2) ≫= f = (l1 ≫= f) ++ (l2 ≫= f).
Proof. by induction l1; csimpl; rewrite <-?(assoc_L (++)); f_equal. Qed.
Lemma elem_of_list_bind (x : B) (l : list A) :
x ∈ l ≫= f ↔ ∃ y, x ∈ f y ∧ y ∈ l.
Proof.
split.
- induction l as [|y l IH]; csimpl; [inv 1|].
rewrite elem_of_app. intros [?|?].
+ ∃ y. split; [done | by left].
+ destruct IH as [z [??]]; [done|]. ∃ z. split; [done | by right].
- intros [y [Hx Hy]]. induction Hy; csimpl; rewrite elem_of_app; intuition.
Qed.
Lemma Forall_bind (P : B → Prop) l :
Forall P (l ≫= f) ↔ Forall (Forall P ∘ f) l.
Proof.
split.
- induction l; csimpl; rewrite ?Forall_app; constructor; csimpl; intuition.
- induction 1; csimpl; rewrite ?Forall_app; auto.
Qed.
Lemma Forall2_bind {C D} (g : C → list D) (P : B → D → Prop) l1 l2 :
Forall2 (λ x1 x2, Forall2 P (f x1) (g x2)) l1 l2 →
Forall2 P (l1 ≫= f) (l2 ≫= g).
Proof. induction 1; csimpl; auto using Forall2_app. Qed.
Lemma NoDup_bind l :
(∀ x1 x2 y, x1 ∈ l → x2 ∈ l → y ∈ f x1 → y ∈ f x2 → x1 = x2) →
(∀ x, x ∈ l → NoDup (f x)) → NoDup l → NoDup (l ≫= f).
Proof.
intros Hinj Hf. induction 1 as [|x l ?? IH]; csimpl; [constructor|].
apply NoDup_app. split_and!.
- eauto 10 using elem_of_list_here.
- intros y ? (x'&?&?)%elem_of_list_bind.
destruct (Hinj x x' y); auto using elem_of_list_here, elem_of_list_further.
- eauto 10 using elem_of_list_further.
Qed.
End bind.
Global Instance list_join_proper `{!Equiv A} :
Proper ((≡) ==> (≡@{list A})) mjoin.
Proof. induction 1; simpl; [constructor|solve_proper]. Qed.
Section ret_join.
Context {A : Type}.
Lemma list_join_bind (ls : list (list A)) : mjoin ls = ls ≫= id.
Proof. by induction ls; f_equal/=. Qed.
Global Instance join_Permutation : Proper ((≡ₚ@{list A}) ==> (≡ₚ)) mjoin.
Proof. intros ?? E. by rewrite !list_join_bind, E. Qed.
Lemma elem_of_list_ret (x y : A) : x ∈ @mret list _ A y ↔ x = y.
Proof. apply elem_of_list_singleton. Qed.
Lemma elem_of_list_join (x : A) (ls : list (list A)) :
x ∈ mjoin ls ↔ ∃ l : list A, x ∈ l ∧ l ∈ ls.
Proof. by rewrite list_join_bind, elem_of_list_bind. Qed.
Lemma join_nil (ls : list (list A)) : mjoin ls = [] ↔ Forall (.= []) ls.
Proof.
split; [|by induction 1 as [|[|??] ?]].
by induction ls as [|[|??] ?]; constructor; auto.
Qed.
Lemma join_nil_1 (ls : list (list A)) : mjoin ls = [] → Forall (.= []) ls.
Proof. by rewrite join_nil. Qed.
Lemma join_nil_2 (ls : list (list A)) : Forall (.= []) ls → mjoin ls = [].
Proof. by rewrite join_nil. Qed.
Lemma join_app (l1 l2 : list (list A)) :
mjoin (l1 ++ l2) = mjoin l1 ++ mjoin l2.
Proof.
induction l1 as [|x l1 IH]; simpl; [done|]. by rewrite <-(assoc_L _ _), IH.
Qed.
Lemma Forall_join (P : A → Prop) (ls: list (list A)) :
Forall (Forall P) ls → Forall P (mjoin ls).
Proof. induction 1; simpl; auto using Forall_app_2. Qed.
Lemma Forall2_join {B} (P : A → B → Prop) ls1 ls2 :
Forall2 (Forall2 P) ls1 ls2 → Forall2 P (mjoin ls1) (mjoin ls2).
Proof. induction 1; simpl; auto using Forall2_app. Qed.
End ret_join.
Global Instance mapM_proper `{!Equiv A, !Equiv B} :
Proper (((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{option (list B)})) mapM.
Proof.
induction 2; csimpl; repeat (f_equiv || constructor || intro || auto).
Qed.
Section mapM.
Context {A B : Type} (f : A → option B).
Lemma mapM_ext (g : A → option B) l : (∀ x, f x = g x) → mapM f l = mapM g l.
Proof. intros Hfg. by induction l as [|?? IHl]; simpl; rewrite ?Hfg, ?IHl. Qed.
Lemma Forall2_mapM_ext (g : A → option B) l k :
Forall2 (λ x y, f x = g y) l k → mapM f l = mapM g k.
Proof. induction 1 as [|???? Hfg ? IH]; simpl; [done|]. by rewrite Hfg, IH. Qed.
Lemma Forall_mapM_ext (g : A → option B) l :
Forall (λ x, f x = g x) l → mapM f l = mapM g l.
Proof. induction 1 as [|?? Hfg ? IH]; simpl; [done|]. by rewrite Hfg, IH. Qed.
Lemma mapM_Some_1 l k : mapM f l = Some k → Forall2 (λ x y, f x = Some y) l k.
Proof.
revert k. induction l as [|x l]; intros [|y k]; simpl; try done.
- destruct (f x); simpl; [|discriminate]. by destruct (mapM f l).
- destruct (f x) eqn:?; intros; simplify_option_eq; auto.
Qed.
Lemma mapM_Some_2 l k : Forall2 (λ x y, f x = Some y) l k → mapM f l = Some k.
Proof.
induction 1 as [|???? Hf ? IH]; simpl; [done |].
rewrite Hf. simpl. by rewrite IH.
Qed.
Lemma mapM_Some l k : mapM f l = Some k ↔ Forall2 (λ x y, f x = Some y) l k.
Proof. split; auto using mapM_Some_1, mapM_Some_2. Qed.
Lemma length_mapM l k : mapM f l = Some k → length l = length k.
Proof. intros. by eapply Forall2_length, mapM_Some_1. Qed.
Lemma mapM_None_1 l : mapM f l = None → Exists (λ x, f x = None) l.
Proof.
induction l as [|x l IH]; simpl; [done|].
destruct (f x) eqn:?; simpl; eauto. by destruct (mapM f l); eauto.
Qed.
Lemma mapM_None_2 l : Exists (λ x, f x = None) l → mapM f l = None.
Proof.
induction 1 as [x l Hx|x l ? IH]; simpl; [by rewrite Hx|].
by destruct (f x); simpl; rewrite ?IH.
Qed.
Lemma mapM_None l : mapM f l = None ↔ Exists (λ x, f x = None) l.
Proof. split; auto using mapM_None_1, mapM_None_2. Qed.
Lemma mapM_is_Some_1 l : is_Some (mapM f l) → Forall (is_Some ∘ f) l.
Proof.
unfold compose. setoid_rewrite <-not_eq_None_Some.
rewrite mapM_None. apply (not_Exists_Forall _).
Qed.
Lemma mapM_is_Some_2 l : Forall (is_Some ∘ f) l → is_Some (mapM f l).
Proof.
unfold compose. setoid_rewrite <-not_eq_None_Some.
rewrite mapM_None. apply (Forall_not_Exists _).
Qed.
Lemma mapM_is_Some l : is_Some (mapM f l) ↔ Forall (is_Some ∘ f) l.
Proof. split; auto using mapM_is_Some_1, mapM_is_Some_2. Qed.
Lemma mapM_fmap_Forall_Some (g : B → A) (l : list B) :
Forall (λ x, f (g x) = Some x) l → mapM f (g <$> l) = Some l.
Proof. by induction 1; simpl; simplify_option_eq. Qed.
Lemma mapM_fmap_Some (g : B → A) (l : list B) :
(∀ x, f (g x) = Some x) → mapM f (g <$> l) = Some l.
Proof. intros. by apply mapM_fmap_Forall_Some, Forall_true. Qed.
Lemma mapM_fmap_Forall2_Some_inv (g : B → A) (l : list A) (k : list B) :
mapM f l = Some k → Forall2 (λ x y, f x = Some y → g y = x) l k → g <$> k = l.
Proof. induction 2; simplify_option_eq; naive_solver. Qed.
Lemma mapM_fmap_Some_inv (g : B → A) (l : list A) (k : list B) :
mapM f l = Some k → (∀ x y, f x = Some y → g y = x) → g <$> k = l.
Proof. eauto using mapM_fmap_Forall2_Some_inv, Forall2_true, length_mapM. Qed.
End mapM.
Lemma imap_const {A B} (f : A → B) l : imap (const f) l = f <$> l.
Proof. induction l; f_equal/=; auto. Qed.
Global Instance imap_proper `{!Equiv A, !Equiv B} :
Proper (pointwise_relation _ ((≡) ==> (≡)) ==> (≡@{list A}) ==> (≡@{list B}))
imap.
Proof.
intros f f' Hf l l' Hl. revert f f' Hf.
induction Hl as [|x1 x2 l1 l2 ?? IH]; intros f f' Hf; simpl; constructor.
- by apply Hf.
- apply IH. intros i y y' ?; simpl. by apply Hf.
Qed.
Section imap.
Context {A B : Type} (f : nat → A → B).
Lemma imap_ext g l :
(∀ i x, l !! i = Some x → f i x = g i x) → imap f l = imap g l.
Proof. revert f g; induction l as [|x l IH]; intros; f_equal/=; eauto. Qed.
Lemma imap_nil : imap f [] = [].
Proof. done. Qed.
Lemma imap_app l1 l2 :
imap f (l1 ++ l2) = imap f l1 ++ imap (λ n, f (length l1 + n)) l2.
Proof.
revert f. induction l1 as [|x l1 IH]; intros f; f_equal/=.
by rewrite IH.
Qed.
Lemma imap_cons x l : imap f (x :: l) = f 0 x :: imap (f ∘ S) l.
Proof. done. Qed.
Lemma imap_fmap {C} (g : C → A) l : imap f (g <$> l) = imap (λ n, f n ∘ g) l.
Proof. revert f. induction l; intros; f_equal/=; eauto. Qed.
Lemma fmap_imap {C} (g : B → C) l : g <$> imap f l = imap (λ n, g ∘ f n) l.
Proof. revert f. induction l; intros; f_equal/=; eauto. Qed.
Lemma list_lookup_imap l i : imap f l !! i = f i <$> l !! i.
Proof.
revert f i. induction l as [|x l IH]; intros f [|i]; f_equal/=; auto.
by rewrite IH.
Qed.
Lemma list_lookup_imap_Some l i x :
imap f l !! i = Some x ↔ ∃ y, l !! i = Some y ∧ x = f i y.
Proof. by rewrite list_lookup_imap, fmap_Some. Qed.
Lemma list_lookup_total_imap `{!Inhabited A, !Inhabited B} l i :
i < length l → imap f l !!! i = f i (l !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, list_lookup_imap, Hx.
Qed.
Lemma length_imap l : length (imap f l) = length l.
Proof. revert f. induction l; simpl; eauto. Qed.
Lemma elem_of_lookup_imap_1 l x :
x ∈ imap f l → ∃ i y, x = f i y ∧ l !! i = Some y.
Proof.
intros [i Hin]%elem_of_list_lookup. rewrite list_lookup_imap in Hin.
simplify_option_eq; naive_solver.
Qed.
Lemma elem_of_lookup_imap_2 l x i : l !! i = Some x → f i x ∈ imap f l.
Proof.
intros Hl. rewrite elem_of_list_lookup.
∃ i. by rewrite list_lookup_imap, Hl.
Qed.
Lemma elem_of_lookup_imap l x :
x ∈ imap f l ↔ ∃ i y, x = f i y ∧ l !! i = Some y.
Proof. naive_solver eauto using elem_of_lookup_imap_1, elem_of_lookup_imap_2. Qed.
End imap.
Properties of the permutations function
Section permutations.
Context {A : Type}.
Implicit Types x y z : A.
Implicit Types l : list A.
Lemma interleave_cons x l : x :: l ∈ interleave x l.
Proof. destruct l; simpl; rewrite elem_of_cons; auto. Qed.
Lemma interleave_Permutation x l l' : l' ∈ interleave x l → l' ≡ₚ x :: l.
Proof.
revert l'. induction l as [|y l IH]; intros l'; simpl.
- rewrite elem_of_list_singleton. by intros →.
- rewrite elem_of_cons, elem_of_list_fmap. intros [->|[? [-> H]]]; [done|].
rewrite (IH _ H). constructor.
Qed.
Lemma permutations_refl l : l ∈ permutations l.
Proof.
induction l; simpl; [by apply elem_of_list_singleton|].
apply elem_of_list_bind. eauto using interleave_cons.
Qed.
Lemma permutations_skip x l l' :
l ∈ permutations l' → x :: l ∈ permutations (x :: l').
Proof. intro. apply elem_of_list_bind; eauto using interleave_cons. Qed.
Lemma permutations_swap x y l : y :: x :: l ∈ permutations (x :: y :: l).
Proof.
simpl. apply elem_of_list_bind. ∃ (y :: l). split; simpl.
- destruct l; csimpl; rewrite !elem_of_cons; auto.
- apply elem_of_list_bind. simpl.
eauto using interleave_cons, permutations_refl.
Qed.
Lemma permutations_nil l : l ∈ permutations [] ↔ l = [].
Proof. simpl. by rewrite elem_of_list_singleton. Qed.
Lemma interleave_interleave_toggle x1 x2 l1 l2 l3 :
l1 ∈ interleave x1 l2 → l2 ∈ interleave x2 l3 → ∃ l4,
l1 ∈ interleave x2 l4 ∧ l4 ∈ interleave x1 l3.
Proof.
revert l1 l2. induction l3 as [|y l3 IH]; intros l1 l2; simpl.
{ rewrite !elem_of_list_singleton. intros ? →. ∃ [x1].
change (interleave x2 [x1]) with ([[x2; x1]] ++ [[x1; x2]]).
by rewrite (comm (++)), elem_of_list_singleton. }
rewrite elem_of_cons, elem_of_list_fmap.
intros Hl1 [? | [l2' [??]]]; simplify_eq/=.
- rewrite !elem_of_cons, elem_of_list_fmap in Hl1.
destruct Hl1 as [? | [? | [l4 [??]]]]; subst.
+ ∃ (x1 :: y :: l3). csimpl. rewrite !elem_of_cons. tauto.
+ ∃ (x1 :: y :: l3). csimpl. rewrite !elem_of_cons. tauto.
+ ∃ l4. simpl. rewrite elem_of_cons. auto using interleave_cons.
- rewrite elem_of_cons, elem_of_list_fmap in Hl1.
destruct Hl1 as [? | [l1' [??]]]; subst.
+ ∃ (x1 :: y :: l3). csimpl.
rewrite !elem_of_cons, !elem_of_list_fmap.
split; [| by auto]. right. right. ∃ (y :: l2').
rewrite elem_of_list_fmap. naive_solver.
+ destruct (IH l1' l2') as [l4 [??]]; auto. ∃ (y :: l4). simpl.
rewrite !elem_of_cons, !elem_of_list_fmap. naive_solver.
Qed.
Lemma permutations_interleave_toggle x l1 l2 l3 :
l1 ∈ permutations l2 → l2 ∈ interleave x l3 → ∃ l4,
l1 ∈ interleave x l4 ∧ l4 ∈ permutations l3.
Proof.
revert l1 l2. induction l3 as [|y l3 IH]; intros l1 l2; simpl.
{ rewrite elem_of_list_singleton. intros Hl1 →. eexists [].
by rewrite elem_of_list_singleton. }
rewrite elem_of_cons, elem_of_list_fmap.
intros Hl1 [? | [l2' [? Hl2']]]; simplify_eq/=.
- rewrite elem_of_list_bind in Hl1.
destruct Hl1 as [l1' [??]]. by ∃ l1'.
- rewrite elem_of_list_bind in Hl1. setoid_rewrite elem_of_list_bind.
destruct Hl1 as [l1' [??]]. destruct (IH l1' l2') as (l1''&?&?); auto.
destruct (interleave_interleave_toggle y x l1 l1' l1'') as (?&?&?); eauto.
Qed.
Lemma permutations_trans l1 l2 l3 :
l1 ∈ permutations l2 → l2 ∈ permutations l3 → l1 ∈ permutations l3.
Proof.
revert l1 l2. induction l3 as [|x l3 IH]; intros l1 l2; simpl.
- rewrite !elem_of_list_singleton. intros Hl1 ->; simpl in ×.
by rewrite elem_of_list_singleton in Hl1.
- rewrite !elem_of_list_bind. intros Hl1 [l2' [Hl2 Hl2']].
destruct (permutations_interleave_toggle x l1 l2 l2') as [? [??]]; eauto.
Qed.
Lemma permutations_Permutation l l' : l' ∈ permutations l ↔ l ≡ₚ l'.
Proof.
split.
- revert l'. induction l; simpl; intros l''.
+ rewrite elem_of_list_singleton. by intros →.
+ rewrite elem_of_list_bind. intros [l' [Hl'' ?]].
rewrite (interleave_Permutation _ _ _ Hl''). constructor; auto.
- induction 1; eauto using permutations_refl,
permutations_skip, permutations_swap, permutations_trans.
Qed.
End permutations.
Context {A : Type}.
Implicit Types x y z : A.
Implicit Types l : list A.
Lemma interleave_cons x l : x :: l ∈ interleave x l.
Proof. destruct l; simpl; rewrite elem_of_cons; auto. Qed.
Lemma interleave_Permutation x l l' : l' ∈ interleave x l → l' ≡ₚ x :: l.
Proof.
revert l'. induction l as [|y l IH]; intros l'; simpl.
- rewrite elem_of_list_singleton. by intros →.
- rewrite elem_of_cons, elem_of_list_fmap. intros [->|[? [-> H]]]; [done|].
rewrite (IH _ H). constructor.
Qed.
Lemma permutations_refl l : l ∈ permutations l.
Proof.
induction l; simpl; [by apply elem_of_list_singleton|].
apply elem_of_list_bind. eauto using interleave_cons.
Qed.
Lemma permutations_skip x l l' :
l ∈ permutations l' → x :: l ∈ permutations (x :: l').
Proof. intro. apply elem_of_list_bind; eauto using interleave_cons. Qed.
Lemma permutations_swap x y l : y :: x :: l ∈ permutations (x :: y :: l).
Proof.
simpl. apply elem_of_list_bind. ∃ (y :: l). split; simpl.
- destruct l; csimpl; rewrite !elem_of_cons; auto.
- apply elem_of_list_bind. simpl.
eauto using interleave_cons, permutations_refl.
Qed.
Lemma permutations_nil l : l ∈ permutations [] ↔ l = [].
Proof. simpl. by rewrite elem_of_list_singleton. Qed.
Lemma interleave_interleave_toggle x1 x2 l1 l2 l3 :
l1 ∈ interleave x1 l2 → l2 ∈ interleave x2 l3 → ∃ l4,
l1 ∈ interleave x2 l4 ∧ l4 ∈ interleave x1 l3.
Proof.
revert l1 l2. induction l3 as [|y l3 IH]; intros l1 l2; simpl.
{ rewrite !elem_of_list_singleton. intros ? →. ∃ [x1].
change (interleave x2 [x1]) with ([[x2; x1]] ++ [[x1; x2]]).
by rewrite (comm (++)), elem_of_list_singleton. }
rewrite elem_of_cons, elem_of_list_fmap.
intros Hl1 [? | [l2' [??]]]; simplify_eq/=.
- rewrite !elem_of_cons, elem_of_list_fmap in Hl1.
destruct Hl1 as [? | [? | [l4 [??]]]]; subst.
+ ∃ (x1 :: y :: l3). csimpl. rewrite !elem_of_cons. tauto.
+ ∃ (x1 :: y :: l3). csimpl. rewrite !elem_of_cons. tauto.
+ ∃ l4. simpl. rewrite elem_of_cons. auto using interleave_cons.
- rewrite elem_of_cons, elem_of_list_fmap in Hl1.
destruct Hl1 as [? | [l1' [??]]]; subst.
+ ∃ (x1 :: y :: l3). csimpl.
rewrite !elem_of_cons, !elem_of_list_fmap.
split; [| by auto]. right. right. ∃ (y :: l2').
rewrite elem_of_list_fmap. naive_solver.
+ destruct (IH l1' l2') as [l4 [??]]; auto. ∃ (y :: l4). simpl.
rewrite !elem_of_cons, !elem_of_list_fmap. naive_solver.
Qed.
Lemma permutations_interleave_toggle x l1 l2 l3 :
l1 ∈ permutations l2 → l2 ∈ interleave x l3 → ∃ l4,
l1 ∈ interleave x l4 ∧ l4 ∈ permutations l3.
Proof.
revert l1 l2. induction l3 as [|y l3 IH]; intros l1 l2; simpl.
{ rewrite elem_of_list_singleton. intros Hl1 →. eexists [].
by rewrite elem_of_list_singleton. }
rewrite elem_of_cons, elem_of_list_fmap.
intros Hl1 [? | [l2' [? Hl2']]]; simplify_eq/=.
- rewrite elem_of_list_bind in Hl1.
destruct Hl1 as [l1' [??]]. by ∃ l1'.
- rewrite elem_of_list_bind in Hl1. setoid_rewrite elem_of_list_bind.
destruct Hl1 as [l1' [??]]. destruct (IH l1' l2') as (l1''&?&?); auto.
destruct (interleave_interleave_toggle y x l1 l1' l1'') as (?&?&?); eauto.
Qed.
Lemma permutations_trans l1 l2 l3 :
l1 ∈ permutations l2 → l2 ∈ permutations l3 → l1 ∈ permutations l3.
Proof.
revert l1 l2. induction l3 as [|x l3 IH]; intros l1 l2; simpl.
- rewrite !elem_of_list_singleton. intros Hl1 ->; simpl in ×.
by rewrite elem_of_list_singleton in Hl1.
- rewrite !elem_of_list_bind. intros Hl1 [l2' [Hl2 Hl2']].
destruct (permutations_interleave_toggle x l1 l2 l2') as [? [??]]; eauto.
Qed.
Lemma permutations_Permutation l l' : l' ∈ permutations l ↔ l ≡ₚ l'.
Proof.
split.
- revert l'. induction l; simpl; intros l''.
+ rewrite elem_of_list_singleton. by intros →.
+ rewrite elem_of_list_bind. intros [l' [Hl'' ?]].
rewrite (interleave_Permutation _ _ _ Hl''). constructor; auto.
- induction 1; eauto using permutations_refl,
permutations_skip, permutations_swap, permutations_trans.
Qed.
End permutations.
Properties of the folding functions
Note that foldr has much better support, so when in doubt, it should be preferred over foldl.
Definition foldr_app := @fold_right_app.
Lemma foldr_cons {A B} (f : B → A → A) (a : A) l x :
foldr f a (x :: l) = f x (foldr f a l).
Proof. done. Qed.
Lemma foldr_snoc {A B} (f : B → A → A) (a : A) l x :
foldr f a (l ++ [x]) = foldr f (f x a) l.
Proof. rewrite foldr_app. done. Qed.
Lemma foldr_fmap {A B C} (f : B → A → A) x (l : list C) g :
foldr f x (g <$> l) = foldr (λ b a, f (g b) a) x l.
Proof. induction l; f_equal/=; auto. Qed.
Lemma foldr_ext {A B} (f1 f2 : B → A → A) x1 x2 l1 l2 :
(∀ b a, f1 b a = f2 b a) → l1 = l2 → x1 = x2 → foldr f1 x1 l1 = foldr f2 x2 l2.
Proof. intros Hf → →. induction l2 as [|x l2 IH]; f_equal/=; by rewrite Hf, IH. Qed.
Lemma foldr_permutation {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{Hf : !∀ x, Proper (R ==> R) (f x)} (l1 l2 : list A) :
(∀ j1 a1 j2 a2 b,
j1 ≠ j2 → l1 !! j1 = Some a1 → l1 !! j2 = Some a2 →
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
l1 ≡ₚ l2 → R (foldr f b l1) (foldr f b l2).
Proof.
intros Hf'. induction 1 as [|x l1 l2 _ IH|x y l|l1 l2 l3 Hl12 IH _ IH']; simpl.
- done.
- apply Hf, IH; eauto.
- apply (Hf' 0 _ 1); eauto.
- etrans; [eapply IH, Hf'|].
apply IH'; intros j1 a1 j2 a2 b' ???.
symmetry in Hl12; apply Permutation_inj in Hl12 as [_ (g&?&Hg)].
apply (Hf' (g j1) _ (g j2)); [naive_solver|by rewrite <-Hg..].
Qed.
Lemma foldr_permutation_proper {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{!∀ x, Proper (R ==> R) (f x)}
(Hf : ∀ a1 a2 b, R (f a1 (f a2 b)) (f a2 (f a1 b))) :
Proper ((≡ₚ) ==> R) (foldr f b).
Proof. intros l1 l2 Hl. apply foldr_permutation; auto. Qed.
Global Instance foldr_permutation_proper' {A} (R : relation A) `{!PreOrder R}
(f : A → A → A) (a : A) `{!∀ a, Proper (R ==> R) (f a), !Assoc R f, !Comm R f} :
Proper ((≡ₚ) ==> R) (foldr f a).
Proof.
apply (foldr_permutation_proper R f); [solve_proper|].
assert (Proper (R ==> R ==> R) f).
{ intros a1 a2 Ha b1 b2 Hb. by rewrite Hb, (comm f a1), Ha, (comm f). }
intros a1 a2 b.
by rewrite (assoc f), (comm f _ b), (assoc f), (comm f b), (comm f _ a2).
Qed.
Lemma foldr_cons_permute_strong {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{!∀ a, Proper (R ==> R) (f a)} x l :
(∀ j1 a1 j2 a2 b,
j1 ≠ j2 → (x :: l) !! j1 = Some a1 → (x :: l) !! j2 = Some a2 →
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
R (foldr f b (x :: l)) (foldr f (f x b) l).
Proof.
intros. rewrite <-foldr_snoc.
apply (foldr_permutation _ f b); [done|]. by rewrite Permutation_app_comm.
Qed.
Lemma foldr_cons_permute {A} (f : A → A → A) (a : A) x l :
Assoc (=) f →
Comm (=) f →
foldr f a (x :: l) = foldr f (f x a) l.
Proof.
intros. apply (foldr_cons_permute_strong (=) f a).
intros j1 a1 j2 a2 b _ _ _. by rewrite !(assoc_L f), (comm_L f a1).
Qed.
Lemma foldr_cons {A B} (f : B → A → A) (a : A) l x :
foldr f a (x :: l) = f x (foldr f a l).
Proof. done. Qed.
Lemma foldr_snoc {A B} (f : B → A → A) (a : A) l x :
foldr f a (l ++ [x]) = foldr f (f x a) l.
Proof. rewrite foldr_app. done. Qed.
Lemma foldr_fmap {A B C} (f : B → A → A) x (l : list C) g :
foldr f x (g <$> l) = foldr (λ b a, f (g b) a) x l.
Proof. induction l; f_equal/=; auto. Qed.
Lemma foldr_ext {A B} (f1 f2 : B → A → A) x1 x2 l1 l2 :
(∀ b a, f1 b a = f2 b a) → l1 = l2 → x1 = x2 → foldr f1 x1 l1 = foldr f2 x2 l2.
Proof. intros Hf → →. induction l2 as [|x l2 IH]; f_equal/=; by rewrite Hf, IH. Qed.
Lemma foldr_permutation {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{Hf : !∀ x, Proper (R ==> R) (f x)} (l1 l2 : list A) :
(∀ j1 a1 j2 a2 b,
j1 ≠ j2 → l1 !! j1 = Some a1 → l1 !! j2 = Some a2 →
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
l1 ≡ₚ l2 → R (foldr f b l1) (foldr f b l2).
Proof.
intros Hf'. induction 1 as [|x l1 l2 _ IH|x y l|l1 l2 l3 Hl12 IH _ IH']; simpl.
- done.
- apply Hf, IH; eauto.
- apply (Hf' 0 _ 1); eauto.
- etrans; [eapply IH, Hf'|].
apply IH'; intros j1 a1 j2 a2 b' ???.
symmetry in Hl12; apply Permutation_inj in Hl12 as [_ (g&?&Hg)].
apply (Hf' (g j1) _ (g j2)); [naive_solver|by rewrite <-Hg..].
Qed.
Lemma foldr_permutation_proper {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{!∀ x, Proper (R ==> R) (f x)}
(Hf : ∀ a1 a2 b, R (f a1 (f a2 b)) (f a2 (f a1 b))) :
Proper ((≡ₚ) ==> R) (foldr f b).
Proof. intros l1 l2 Hl. apply foldr_permutation; auto. Qed.
Global Instance foldr_permutation_proper' {A} (R : relation A) `{!PreOrder R}
(f : A → A → A) (a : A) `{!∀ a, Proper (R ==> R) (f a), !Assoc R f, !Comm R f} :
Proper ((≡ₚ) ==> R) (foldr f a).
Proof.
apply (foldr_permutation_proper R f); [solve_proper|].
assert (Proper (R ==> R ==> R) f).
{ intros a1 a2 Ha b1 b2 Hb. by rewrite Hb, (comm f a1), Ha, (comm f). }
intros a1 a2 b.
by rewrite (assoc f), (comm f _ b), (assoc f), (comm f b), (comm f _ a2).
Qed.
Lemma foldr_cons_permute_strong {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{!∀ a, Proper (R ==> R) (f a)} x l :
(∀ j1 a1 j2 a2 b,
j1 ≠ j2 → (x :: l) !! j1 = Some a1 → (x :: l) !! j2 = Some a2 →
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
R (foldr f b (x :: l)) (foldr f (f x b) l).
Proof.
intros. rewrite <-foldr_snoc.
apply (foldr_permutation _ f b); [done|]. by rewrite Permutation_app_comm.
Qed.
Lemma foldr_cons_permute {A} (f : A → A → A) (a : A) x l :
Assoc (=) f →
Comm (=) f →
foldr f a (x :: l) = foldr f (f x a) l.
Proof.
intros. apply (foldr_cons_permute_strong (=) f a).
intros j1 a1 j2 a2 b _ _ _. by rewrite !(assoc_L f), (comm_L f a1).
Qed.
The following lemma shows that folding over a list twice (using the result
of the first fold as input for the second fold) is equivalent to folding over
the list once, *if* the function is idempotent for the elements of the list
and does not care about the order in which elements are processed.
Lemma foldr_idemp_strong {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (b : B) `{!∀ x, Proper (R ==> R) (f x)} (l : list A) :
(∀ j a b,
(f : A → B → B) (b : B) `{!∀ x, Proper (R ==> R) (f x)} (l : list A) :
(∀ j a b,
This is morally idempotence for elements of l
This is morally commutativity + associativity for elements of l
j1 ≠ j2 → l !! j1 = Some a1 → l !! j2 = Some a2 →
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
R (foldr f (foldr f b l) l) (foldr f b l).
Proof.
intros Hfidem Hfcomm. induction l as [|x l IH]; simpl; [done|].
trans (f x (f x (foldr f (foldr f b l) l))).
{ f_equiv. rewrite <-foldr_snoc, <-foldr_cons.
apply (foldr_permutation (flip R) f).
- solve_proper.
- intros j1 a1 j2 a2 b' ???. by apply (Hfcomm j2 _ j1).
- by rewrite <-Permutation_cons_append. }
rewrite <-foldr_cons.
trans (f x (f x (foldr f b l))); [|by apply (Hfidem 0)].
simpl. do 2 f_equiv. apply IH.
- intros j a b' ?. by apply (Hfidem (S j)).
- intros j1 a1 j2 a2 b' ???. apply (Hfcomm (S j1) _ (S j2)); auto with lia.
Qed.
Lemma foldr_idemp {A} (f : A → A → A) (a : A) (l : list A) :
IdemP (=) f →
Assoc (=) f →
Comm (=) f →
foldr f (foldr f a l) l = foldr f a l.
Proof.
intros. apply (foldr_idemp_strong (=) f a).
- intros j a1 a2 _. by rewrite (assoc_L f), (idemp f).
- intros x1 a1 x2 a2 a3 _ _ _. by rewrite !(assoc_L f), (comm_L f a1).
Qed.
Lemma foldr_comm_acc_strong {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (g : B → B) b l :
(∀ x, Proper (R ==> R) (f x)) →
(∀ x y, x ∈ l → R (f x (g y)) (g (f x y))) →
R (foldr f (g b) l) (g (foldr f b l)).
Proof.
intros ? Hcomm. induction l as [|x l IH]; simpl; [done|].
rewrite <-Hcomm by eauto using elem_of_list_here.
by rewrite IH by eauto using elem_of_list_further.
Qed.
Lemma foldr_comm_acc {A B} (f : A → B → B) (g : B → B) (b : B) l :
(∀ x y, f x (g y) = g (f x y)) →
foldr f (g b) l = g (foldr f b l).
Proof. intros. apply (foldr_comm_acc_strong _); [solve_proper|done]. Qed.
Lemma foldl_app {A B} (f : A → B → A) (l k : list B) (a : A) :
foldl f a (l ++ k) = foldl f (foldl f a l) k.
Proof. revert a. induction l; simpl; auto. Qed.
Lemma foldl_snoc {A B} (f : A → B → A) (a : A) l x :
foldl f a (l ++ [x]) = f (foldl f a l) x.
Proof. rewrite foldl_app. done. Qed.
Lemma foldl_fmap {A B C} (f : A → B → A) x (l : list C) g :
foldl f x (g <$> l) = foldl (λ a b, f a (g b)) x l.
Proof. revert x. induction l; f_equal/=; auto. Qed.
R (f a1 (f a2 b)) (f a2 (f a1 b))) →
R (foldr f (foldr f b l) l) (foldr f b l).
Proof.
intros Hfidem Hfcomm. induction l as [|x l IH]; simpl; [done|].
trans (f x (f x (foldr f (foldr f b l) l))).
{ f_equiv. rewrite <-foldr_snoc, <-foldr_cons.
apply (foldr_permutation (flip R) f).
- solve_proper.
- intros j1 a1 j2 a2 b' ???. by apply (Hfcomm j2 _ j1).
- by rewrite <-Permutation_cons_append. }
rewrite <-foldr_cons.
trans (f x (f x (foldr f b l))); [|by apply (Hfidem 0)].
simpl. do 2 f_equiv. apply IH.
- intros j a b' ?. by apply (Hfidem (S j)).
- intros j1 a1 j2 a2 b' ???. apply (Hfcomm (S j1) _ (S j2)); auto with lia.
Qed.
Lemma foldr_idemp {A} (f : A → A → A) (a : A) (l : list A) :
IdemP (=) f →
Assoc (=) f →
Comm (=) f →
foldr f (foldr f a l) l = foldr f a l.
Proof.
intros. apply (foldr_idemp_strong (=) f a).
- intros j a1 a2 _. by rewrite (assoc_L f), (idemp f).
- intros x1 a1 x2 a2 a3 _ _ _. by rewrite !(assoc_L f), (comm_L f a1).
Qed.
Lemma foldr_comm_acc_strong {A B} (R : relation B) `{!PreOrder R}
(f : A → B → B) (g : B → B) b l :
(∀ x, Proper (R ==> R) (f x)) →
(∀ x y, x ∈ l → R (f x (g y)) (g (f x y))) →
R (foldr f (g b) l) (g (foldr f b l)).
Proof.
intros ? Hcomm. induction l as [|x l IH]; simpl; [done|].
rewrite <-Hcomm by eauto using elem_of_list_here.
by rewrite IH by eauto using elem_of_list_further.
Qed.
Lemma foldr_comm_acc {A B} (f : A → B → B) (g : B → B) (b : B) l :
(∀ x y, f x (g y) = g (f x y)) →
foldr f (g b) l = g (foldr f b l).
Proof. intros. apply (foldr_comm_acc_strong _); [solve_proper|done]. Qed.
Lemma foldl_app {A B} (f : A → B → A) (l k : list B) (a : A) :
foldl f a (l ++ k) = foldl f (foldl f a l) k.
Proof. revert a. induction l; simpl; auto. Qed.
Lemma foldl_snoc {A B} (f : A → B → A) (a : A) l x :
foldl f a (l ++ [x]) = f (foldl f a l) x.
Proof. rewrite foldl_app. done. Qed.
Lemma foldl_fmap {A B C} (f : A → B → A) x (l : list C) g :
foldl f x (g <$> l) = foldl (λ a b, f a (g b)) x l.
Proof. revert x. induction l; f_equal/=; auto. Qed.
Global Instance zip_with_proper `{!Equiv A, !Equiv B, !Equiv C} :
Proper (((≡) ==> (≡) ==> (≡)) ==>
(≡@{list A}) ==> (≡@{list B}) ==> (≡@{list C})) zip_with.
Proof.
intros f1 f2 Hf. induction 1; destruct 1; simpl; [constructor..|].
f_equiv; [|by auto]. by apply Hf.
Qed.
Section zip_with.
Context {A B C : Type} (f : A → B → C).
Implicit Types x : A.
Implicit Types y : B.
Implicit Types l : list A.
Implicit Types k : list B.
Lemma zip_with_nil_r l : zip_with f l [] = [].
Proof. by destruct l. Qed.
Lemma zip_with_app l1 l2 k1 k2 :
length l1 = length k1 →
zip_with f (l1 ++ l2) (k1 ++ k2) = zip_with f l1 k1 ++ zip_with f l2 k2.
Proof. rewrite <-Forall2_same_length. induction 1; f_equal/=; auto. Qed.
Lemma zip_with_app_l l1 l2 k :
zip_with f (l1 ++ l2) k
= zip_with f l1 (take (length l1) k) ++ zip_with f l2 (drop (length l1) k).
Proof.
revert k. induction l1; intros [|??]; f_equal/=; auto. by destruct l2.
Qed.
Lemma zip_with_app_r l k1 k2 :
zip_with f l (k1 ++ k2)
= zip_with f (take (length k1) l) k1 ++ zip_with f (drop (length k1) l) k2.
Proof. revert l. induction k1; intros [|??]; f_equal/=; auto. Qed.
Lemma zip_with_flip l k : zip_with (flip f) k l = zip_with f l k.
Proof. revert k. induction l; intros [|??]; f_equal/=; auto. Qed.
Lemma zip_with_ext (g : A → B → C) l1 l2 k1 k2 :
(∀ x y, f x y = g x y) → l1 = l2 → k1 = k2 →
zip_with f l1 k1 = zip_with g l2 k2.
Proof. intros ? <-<-. revert k1. by induction l1; intros [|??]; f_equal/=. Qed.
Lemma Forall_zip_with_ext_l (g : A → B → C) l k1 k2 :
Forall (λ x, ∀ y, f x y = g x y) l → k1 = k2 →
zip_with f l k1 = zip_with g l k2.
Proof. intros Hl <-. revert k1. by induction Hl; intros [|??]; f_equal/=. Qed.
Lemma Forall_zip_with_ext_r (g : A → B → C) l1 l2 k :
l1 = l2 → Forall (λ y, ∀ x, f x y = g x y) k →
zip_with f l1 k = zip_with g l2 k.
Proof. intros <- Hk. revert l1. by induction Hk; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fmap_l {D} (g : D → A) lD k :
zip_with f (g <$> lD) k = zip_with (λ z, f (g z)) lD k.
Proof. revert k. by induction lD; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fmap_r {D} (g : D → B) l kD :
zip_with f l (g <$> kD) = zip_with (λ x z, f x (g z)) l kD.
Proof. revert kD. by induction l; intros [|??]; f_equal/=. Qed.
Lemma zip_with_nil_inv l k : zip_with f l k = [] → l = [] ∨ k = [].
Proof. destruct l, k; intros; simplify_eq/=; auto. Qed.
Lemma zip_with_cons_inv l k z lC :
zip_with f l k = z :: lC →
∃ x y l' k', z = f x y ∧ lC = zip_with f l' k' ∧ l = x :: l' ∧ k = y :: k'.
Proof. intros. destruct l, k; simplify_eq/=; repeat eexists. Qed.
Lemma zip_with_app_inv l k lC1 lC2 :
zip_with f l k = lC1 ++ lC2 →
∃ l1 k1 l2 k2, lC1 = zip_with f l1 k1 ∧ lC2 = zip_with f l2 k2 ∧
l = l1 ++ l2 ∧ k = k1 ++ k2 ∧ length l1 = length k1.
Proof.
revert l k. induction lC1 as [|z lC1 IH]; simpl.
{ intros l k ?. by eexists [], [], l, k. }
intros [|x l] [|y k] ?; simplify_eq/=.
destruct (IH l k) as (l1&k1&l2&k2&->&->&->&->&?); [done |].
∃ (x :: l1), (y :: k1), l2, k2; simpl; auto with congruence.
Qed.
Lemma zip_with_inj `{!Inj2 (=) (=) (=) f} l1 l2 k1 k2 :
length l1 = length k1 → length l2 = length k2 →
zip_with f l1 k1 = zip_with f l2 k2 → l1 = l2 ∧ k1 = k2.
Proof.
rewrite <-!Forall2_same_length. intros Hl. revert l2 k2.
induction Hl; intros ?? [] ?; f_equal; naive_solver.
Qed.
Lemma length_zip_with l k :
length (zip_with f l k) = min (length l) (length k).
Proof. revert k. induction l; intros [|??]; simpl; auto with lia. Qed.
Lemma length_zip_with_l l k :
length l ≤ length k → length (zip_with f l k) = length l.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_l_eq l k :
length l = length k → length (zip_with f l k) = length l.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_r l k :
length k ≤ length l → length (zip_with f l k) = length k.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_r_eq l k :
length k = length l → length (zip_with f l k) = length k.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_same_l P l k :
Forall2 P l k → length (zip_with f l k) = length l.
Proof. induction 1; simpl; auto. Qed.
Lemma length_zip_with_same_r P l k :
Forall2 P l k → length (zip_with f l k) = length k.
Proof. induction 1; simpl; auto. Qed.
Lemma lookup_zip_with l k i :
zip_with f l k !! i = (x ← l !! i; y ← k !! i; Some (f x y)).
Proof.
revert k i. induction l; intros [|??] [|?]; f_equal/=; auto.
by destruct (_ !! _).
Qed.
Lemma lookup_total_zip_with `{!Inhabited A, !Inhabited B, !Inhabited C} l k i :
i < length l → i < length k → zip_with f l k !!! i = f (l !!! i) (k !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2 [y Hy]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, lookup_zip_with, Hx, Hy.
Qed.
Lemma lookup_zip_with_Some l k i z :
zip_with f l k !! i = Some z
↔ ∃ x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof. rewrite lookup_zip_with. destruct (l !! i), (k !! i); naive_solver. Qed.
Lemma lookup_zip_with_None l k i :
zip_with f l k !! i = None
↔ l !! i = None ∨ k !! i = None.
Proof. rewrite lookup_zip_with. destruct (l !! i), (k !! i); naive_solver. Qed.
Lemma insert_zip_with l k i x y :
<[i:=f x y]>(zip_with f l k) = zip_with f (<[i:=x]>l) (<[i:=y]>k).
Proof. revert i k. induction l; intros [|?] [|??]; f_equal/=; auto. Qed.
Lemma fmap_zip_with_l (g : C → A) l k :
(∀ x y, g (f x y) = x) → length l ≤ length k → g <$> zip_with f l k = l.
Proof. revert k. induction l; intros [|??] ??; f_equal/=; auto with lia. Qed.
Lemma fmap_zip_with_r (g : C → B) l k :
(∀ x y, g (f x y) = y) → length k ≤ length l → g <$> zip_with f l k = k.
Proof. revert l. induction k; intros [|??] ??; f_equal/=; auto with lia. Qed.
Lemma zip_with_zip l k : zip_with f l k = uncurry f <$> zip l k.
Proof. revert k. by induction l; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fst_snd lk : zip_with f (lk.*1) (lk.*2) = uncurry f <$> lk.
Proof. by induction lk as [|[]]; f_equal/=. Qed.
Lemma zip_with_replicate n x y :
zip_with f (replicate n x) (replicate n y) = replicate n (f x y).
Proof. by induction n; f_equal/=. Qed.
Lemma zip_with_replicate_l n x k :
length k ≤ n → zip_with f (replicate n x) k = f x <$> k.
Proof. revert n. induction k; intros [|?] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_replicate_r n y l :
length l ≤ n → zip_with f l (replicate n y) = flip f y <$> l.
Proof. revert n. induction l; intros [|?] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_replicate_r_eq n y l :
length l = n → zip_with f l (replicate n y) = flip f y <$> l.
Proof. intros; apply zip_with_replicate_r; lia. Qed.
Lemma zip_with_take n l k :
take n (zip_with f l k) = zip_with f (take n l) (take n k).
Proof. revert n k. by induction l; intros [|?] [|??]; f_equal/=. Qed.
Lemma zip_with_drop n l k :
drop n (zip_with f l k) = zip_with f (drop n l) (drop n k).
Proof.
revert n k. induction l; intros [] []; f_equal/=; auto using zip_with_nil_r.
Qed.
Lemma zip_with_take_l' n l k :
length l `min` length k ≤ n → zip_with f (take n l) k = zip_with f l k.
Proof. revert n k. induction l; intros [] [] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_take_l l k :
zip_with f (take (length k) l) k = zip_with f l k.
Proof. apply zip_with_take_l'; lia. Qed.
Lemma zip_with_take_r' n l k :
length l `min` length k ≤ n → zip_with f l (take n k) = zip_with f l k.
Proof. revert n k. induction l; intros [] [] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_take_r l k :
zip_with f l (take (length l) k) = zip_with f l k.
Proof. apply zip_with_take_r'; lia. Qed.
Lemma zip_with_take_both' n1 n2 l k :
length l `min` length k ≤ n1 → length l `min` length k ≤ n2 →
zip_with f (take n1 l) (take n2 k) = zip_with f l k.
Proof.
intros.
rewrite zip_with_take_l'; [apply zip_with_take_r' | rewrite length_take]; lia.
Qed.
Lemma zip_with_take_both l k :
zip_with f (take (length k) l) (take (length l) k) = zip_with f l k.
Proof. apply zip_with_take_both'; lia. Qed.
Lemma Forall_zip_with_fst (P : A → Prop) (Q : C → Prop) l k :
Forall P l → Forall (λ y, ∀ x, P x → Q (f x y)) k →
Forall Q (zip_with f l k).
Proof. intros Hl. revert k. induction Hl; destruct 1; simpl in *; auto. Qed.
Lemma Forall_zip_with_snd (P : B → Prop) (Q : C → Prop) l k :
Forall (λ x, ∀ y, P y → Q (f x y)) l → Forall P k →
Forall Q (zip_with f l k).
Proof. intros Hl. revert k. induction Hl; destruct 1; simpl in *; auto. Qed.
Lemma elem_of_lookup_zip_with_1 l k (z : C) :
z ∈ zip_with f l k → ∃ i x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof.
intros [i Hin]%elem_of_list_lookup. rewrite lookup_zip_with in Hin.
simplify_option_eq; naive_solver.
Qed.
Lemma elem_of_lookup_zip_with_2 l k x y (z : C) i :
l !! i = Some x → k !! i = Some y → f x y ∈ zip_with f l k.
Proof.
intros Hl Hk. rewrite elem_of_list_lookup.
∃ i. by rewrite lookup_zip_with, Hl, Hk.
Qed.
Lemma elem_of_lookup_zip_with l k (z : C) :
z ∈ zip_with f l k ↔ ∃ i x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof.
naive_solver eauto using
elem_of_lookup_zip_with_1, elem_of_lookup_zip_with_2.
Qed.
Lemma elem_of_zip_with l k (z : C) :
z ∈ zip_with f l k → ∃ x y, z = f x y ∧ x ∈ l ∧ y ∈ k.
Proof.
intros ?%elem_of_lookup_zip_with.
naive_solver eauto using elem_of_list_lookup_2.
Qed.
End zip_with.
Lemma zip_with_diag {A C} (f : A → A → C) l :
zip_with f l l = (λ x, f x x) <$> l.
Proof. induction l as [|?? IH]; [done|]. simpl. rewrite IH. done. Qed.
Section zip.
Context {A B : Type}.
Implicit Types l : list A.
Implicit Types k : list B.
Lemma fst_zip l k : length l ≤ length k → (zip l k).*1 = l.
Proof. by apply fmap_zip_with_l. Qed.
Lemma snd_zip l k : length k ≤ length l → (zip l k).*2 = k.
Proof. by apply fmap_zip_with_r. Qed.
Lemma zip_fst_snd (lk : list (A × B)) : zip (lk.*1) (lk.*2) = lk.
Proof. by induction lk as [|[]]; f_equal/=. Qed.
Lemma Forall2_fst P l1 l2 k1 k2 :
length l2 = length k2 → Forall2 P l1 k1 →
Forall2 (λ x y, P (x.1) (y.1)) (zip l1 l2) (zip k1 k2).
Proof.
rewrite <-Forall2_same_length. intros Hlk2 Hlk1. revert l2 k2 Hlk2.
induction Hlk1; intros ?? [|??????]; simpl; auto.
Qed.
Lemma Forall2_snd P l1 l2 k1 k2 :
length l1 = length k1 → Forall2 P l2 k2 →
Forall2 (λ x y, P (x.2) (y.2)) (zip l1 l2) (zip k1 k2).
Proof.
rewrite <-Forall2_same_length. intros Hlk1 Hlk2. revert l1 k1 Hlk1.
induction Hlk2; intros ?? [|??????]; simpl; auto.
Qed.
Lemma elem_of_zip_l x1 x2 l k :
(x1, x2) ∈ zip l k → x1 ∈ l.
Proof. intros ?%elem_of_zip_with. naive_solver. Qed.
Lemma elem_of_zip_r x1 x2 l k :
(x1, x2) ∈ zip l k → x2 ∈ k.
Proof. intros ?%elem_of_zip_with. naive_solver. Qed.
Lemma length_zip l k :
length (zip l k) = min (length l) (length k).
Proof. by rewrite length_zip_with. Qed.
Lemma zip_nil_inv l k :
zip l k = [] → l = [] ∨ k = [].
Proof. intros. by eapply zip_with_nil_inv. Qed.
Lemma lookup_zip_Some l k i x y :
zip l k !! i = Some (x, y) ↔ l !! i = Some x ∧ k !! i = Some y.
Proof. rewrite lookup_zip_with_Some. naive_solver. Qed.
Lemma lookup_zip_None l k i :
zip l k !! i = None ↔ l !! i = None ∨ k !! i = None.
Proof. by rewrite lookup_zip_with_None. Qed.
End zip.
Lemma zip_diag {A} (l : list A) :
zip l l = (λ x, (x, x)) <$> l.
Proof. apply zip_with_diag. Qed.
Lemma elem_of_zipped_map {A B} (f : list A → list A → A → B) l k x :
x ∈ zipped_map f l k ↔
∃ k' k'' y, k = k' ++ [y] ++ k'' ∧ x = f (reverse k' ++ l) k'' y.
Proof.
split.
- revert l. induction k as [|z k IH]; simpl; intros l; inv 1.
{ by eexists [], k, z. }
destruct (IH (z :: l)) as (k'&k''&y&->&->); [done |].
eexists (z :: k'), k'', y. by rewrite reverse_cons, <-(assoc_L (++)).
- intros (k'&k''&y&->&->). revert l. induction k' as [|z k' IH]; [by left|].
intros l; right. by rewrite reverse_cons, <-!(assoc_L (++)).
Qed.
Section zipped_list_ind.
Context {A} (P : list A → list A → Prop).
Context (Pnil : ∀ l, P l []) (Pcons : ∀ l k x, P (x :: l) k → P l (x :: k)).
Fixpoint zipped_list_ind l k : P l k :=
match k with
| [] ⇒ Pnil _ | x :: k ⇒ Pcons _ _ _ (zipped_list_ind (x :: l) k)
end.
End zipped_list_ind.
Lemma zipped_Forall_app {A} (P : list A → list A → A → Prop) l k k' :
zipped_Forall P l (k ++ k') → zipped_Forall P (reverse k ++ l) k'.
Proof.
revert l. induction k as [|x k IH]; simpl; [done |].
inv 1. rewrite reverse_cons, <-(assoc_L (++)). by apply IH.
Qed.
Proper (((≡) ==> (≡) ==> (≡)) ==>
(≡@{list A}) ==> (≡@{list B}) ==> (≡@{list C})) zip_with.
Proof.
intros f1 f2 Hf. induction 1; destruct 1; simpl; [constructor..|].
f_equiv; [|by auto]. by apply Hf.
Qed.
Section zip_with.
Context {A B C : Type} (f : A → B → C).
Implicit Types x : A.
Implicit Types y : B.
Implicit Types l : list A.
Implicit Types k : list B.
Lemma zip_with_nil_r l : zip_with f l [] = [].
Proof. by destruct l. Qed.
Lemma zip_with_app l1 l2 k1 k2 :
length l1 = length k1 →
zip_with f (l1 ++ l2) (k1 ++ k2) = zip_with f l1 k1 ++ zip_with f l2 k2.
Proof. rewrite <-Forall2_same_length. induction 1; f_equal/=; auto. Qed.
Lemma zip_with_app_l l1 l2 k :
zip_with f (l1 ++ l2) k
= zip_with f l1 (take (length l1) k) ++ zip_with f l2 (drop (length l1) k).
Proof.
revert k. induction l1; intros [|??]; f_equal/=; auto. by destruct l2.
Qed.
Lemma zip_with_app_r l k1 k2 :
zip_with f l (k1 ++ k2)
= zip_with f (take (length k1) l) k1 ++ zip_with f (drop (length k1) l) k2.
Proof. revert l. induction k1; intros [|??]; f_equal/=; auto. Qed.
Lemma zip_with_flip l k : zip_with (flip f) k l = zip_with f l k.
Proof. revert k. induction l; intros [|??]; f_equal/=; auto. Qed.
Lemma zip_with_ext (g : A → B → C) l1 l2 k1 k2 :
(∀ x y, f x y = g x y) → l1 = l2 → k1 = k2 →
zip_with f l1 k1 = zip_with g l2 k2.
Proof. intros ? <-<-. revert k1. by induction l1; intros [|??]; f_equal/=. Qed.
Lemma Forall_zip_with_ext_l (g : A → B → C) l k1 k2 :
Forall (λ x, ∀ y, f x y = g x y) l → k1 = k2 →
zip_with f l k1 = zip_with g l k2.
Proof. intros Hl <-. revert k1. by induction Hl; intros [|??]; f_equal/=. Qed.
Lemma Forall_zip_with_ext_r (g : A → B → C) l1 l2 k :
l1 = l2 → Forall (λ y, ∀ x, f x y = g x y) k →
zip_with f l1 k = zip_with g l2 k.
Proof. intros <- Hk. revert l1. by induction Hk; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fmap_l {D} (g : D → A) lD k :
zip_with f (g <$> lD) k = zip_with (λ z, f (g z)) lD k.
Proof. revert k. by induction lD; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fmap_r {D} (g : D → B) l kD :
zip_with f l (g <$> kD) = zip_with (λ x z, f x (g z)) l kD.
Proof. revert kD. by induction l; intros [|??]; f_equal/=. Qed.
Lemma zip_with_nil_inv l k : zip_with f l k = [] → l = [] ∨ k = [].
Proof. destruct l, k; intros; simplify_eq/=; auto. Qed.
Lemma zip_with_cons_inv l k z lC :
zip_with f l k = z :: lC →
∃ x y l' k', z = f x y ∧ lC = zip_with f l' k' ∧ l = x :: l' ∧ k = y :: k'.
Proof. intros. destruct l, k; simplify_eq/=; repeat eexists. Qed.
Lemma zip_with_app_inv l k lC1 lC2 :
zip_with f l k = lC1 ++ lC2 →
∃ l1 k1 l2 k2, lC1 = zip_with f l1 k1 ∧ lC2 = zip_with f l2 k2 ∧
l = l1 ++ l2 ∧ k = k1 ++ k2 ∧ length l1 = length k1.
Proof.
revert l k. induction lC1 as [|z lC1 IH]; simpl.
{ intros l k ?. by eexists [], [], l, k. }
intros [|x l] [|y k] ?; simplify_eq/=.
destruct (IH l k) as (l1&k1&l2&k2&->&->&->&->&?); [done |].
∃ (x :: l1), (y :: k1), l2, k2; simpl; auto with congruence.
Qed.
Lemma zip_with_inj `{!Inj2 (=) (=) (=) f} l1 l2 k1 k2 :
length l1 = length k1 → length l2 = length k2 →
zip_with f l1 k1 = zip_with f l2 k2 → l1 = l2 ∧ k1 = k2.
Proof.
rewrite <-!Forall2_same_length. intros Hl. revert l2 k2.
induction Hl; intros ?? [] ?; f_equal; naive_solver.
Qed.
Lemma length_zip_with l k :
length (zip_with f l k) = min (length l) (length k).
Proof. revert k. induction l; intros [|??]; simpl; auto with lia. Qed.
Lemma length_zip_with_l l k :
length l ≤ length k → length (zip_with f l k) = length l.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_l_eq l k :
length l = length k → length (zip_with f l k) = length l.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_r l k :
length k ≤ length l → length (zip_with f l k) = length k.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_r_eq l k :
length k = length l → length (zip_with f l k) = length k.
Proof. rewrite length_zip_with; lia. Qed.
Lemma length_zip_with_same_l P l k :
Forall2 P l k → length (zip_with f l k) = length l.
Proof. induction 1; simpl; auto. Qed.
Lemma length_zip_with_same_r P l k :
Forall2 P l k → length (zip_with f l k) = length k.
Proof. induction 1; simpl; auto. Qed.
Lemma lookup_zip_with l k i :
zip_with f l k !! i = (x ← l !! i; y ← k !! i; Some (f x y)).
Proof.
revert k i. induction l; intros [|??] [|?]; f_equal/=; auto.
by destruct (_ !! _).
Qed.
Lemma lookup_total_zip_with `{!Inhabited A, !Inhabited B, !Inhabited C} l k i :
i < length l → i < length k → zip_with f l k !!! i = f (l !!! i) (k !!! i).
Proof.
intros [x Hx]%lookup_lt_is_Some_2 [y Hy]%lookup_lt_is_Some_2.
by rewrite !list_lookup_total_alt, lookup_zip_with, Hx, Hy.
Qed.
Lemma lookup_zip_with_Some l k i z :
zip_with f l k !! i = Some z
↔ ∃ x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof. rewrite lookup_zip_with. destruct (l !! i), (k !! i); naive_solver. Qed.
Lemma lookup_zip_with_None l k i :
zip_with f l k !! i = None
↔ l !! i = None ∨ k !! i = None.
Proof. rewrite lookup_zip_with. destruct (l !! i), (k !! i); naive_solver. Qed.
Lemma insert_zip_with l k i x y :
<[i:=f x y]>(zip_with f l k) = zip_with f (<[i:=x]>l) (<[i:=y]>k).
Proof. revert i k. induction l; intros [|?] [|??]; f_equal/=; auto. Qed.
Lemma fmap_zip_with_l (g : C → A) l k :
(∀ x y, g (f x y) = x) → length l ≤ length k → g <$> zip_with f l k = l.
Proof. revert k. induction l; intros [|??] ??; f_equal/=; auto with lia. Qed.
Lemma fmap_zip_with_r (g : C → B) l k :
(∀ x y, g (f x y) = y) → length k ≤ length l → g <$> zip_with f l k = k.
Proof. revert l. induction k; intros [|??] ??; f_equal/=; auto with lia. Qed.
Lemma zip_with_zip l k : zip_with f l k = uncurry f <$> zip l k.
Proof. revert k. by induction l; intros [|??]; f_equal/=. Qed.
Lemma zip_with_fst_snd lk : zip_with f (lk.*1) (lk.*2) = uncurry f <$> lk.
Proof. by induction lk as [|[]]; f_equal/=. Qed.
Lemma zip_with_replicate n x y :
zip_with f (replicate n x) (replicate n y) = replicate n (f x y).
Proof. by induction n; f_equal/=. Qed.
Lemma zip_with_replicate_l n x k :
length k ≤ n → zip_with f (replicate n x) k = f x <$> k.
Proof. revert n. induction k; intros [|?] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_replicate_r n y l :
length l ≤ n → zip_with f l (replicate n y) = flip f y <$> l.
Proof. revert n. induction l; intros [|?] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_replicate_r_eq n y l :
length l = n → zip_with f l (replicate n y) = flip f y <$> l.
Proof. intros; apply zip_with_replicate_r; lia. Qed.
Lemma zip_with_take n l k :
take n (zip_with f l k) = zip_with f (take n l) (take n k).
Proof. revert n k. by induction l; intros [|?] [|??]; f_equal/=. Qed.
Lemma zip_with_drop n l k :
drop n (zip_with f l k) = zip_with f (drop n l) (drop n k).
Proof.
revert n k. induction l; intros [] []; f_equal/=; auto using zip_with_nil_r.
Qed.
Lemma zip_with_take_l' n l k :
length l `min` length k ≤ n → zip_with f (take n l) k = zip_with f l k.
Proof. revert n k. induction l; intros [] [] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_take_l l k :
zip_with f (take (length k) l) k = zip_with f l k.
Proof. apply zip_with_take_l'; lia. Qed.
Lemma zip_with_take_r' n l k :
length l `min` length k ≤ n → zip_with f l (take n k) = zip_with f l k.
Proof. revert n k. induction l; intros [] [] ?; f_equal/=; auto with lia. Qed.
Lemma zip_with_take_r l k :
zip_with f l (take (length l) k) = zip_with f l k.
Proof. apply zip_with_take_r'; lia. Qed.
Lemma zip_with_take_both' n1 n2 l k :
length l `min` length k ≤ n1 → length l `min` length k ≤ n2 →
zip_with f (take n1 l) (take n2 k) = zip_with f l k.
Proof.
intros.
rewrite zip_with_take_l'; [apply zip_with_take_r' | rewrite length_take]; lia.
Qed.
Lemma zip_with_take_both l k :
zip_with f (take (length k) l) (take (length l) k) = zip_with f l k.
Proof. apply zip_with_take_both'; lia. Qed.
Lemma Forall_zip_with_fst (P : A → Prop) (Q : C → Prop) l k :
Forall P l → Forall (λ y, ∀ x, P x → Q (f x y)) k →
Forall Q (zip_with f l k).
Proof. intros Hl. revert k. induction Hl; destruct 1; simpl in *; auto. Qed.
Lemma Forall_zip_with_snd (P : B → Prop) (Q : C → Prop) l k :
Forall (λ x, ∀ y, P y → Q (f x y)) l → Forall P k →
Forall Q (zip_with f l k).
Proof. intros Hl. revert k. induction Hl; destruct 1; simpl in *; auto. Qed.
Lemma elem_of_lookup_zip_with_1 l k (z : C) :
z ∈ zip_with f l k → ∃ i x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof.
intros [i Hin]%elem_of_list_lookup. rewrite lookup_zip_with in Hin.
simplify_option_eq; naive_solver.
Qed.
Lemma elem_of_lookup_zip_with_2 l k x y (z : C) i :
l !! i = Some x → k !! i = Some y → f x y ∈ zip_with f l k.
Proof.
intros Hl Hk. rewrite elem_of_list_lookup.
∃ i. by rewrite lookup_zip_with, Hl, Hk.
Qed.
Lemma elem_of_lookup_zip_with l k (z : C) :
z ∈ zip_with f l k ↔ ∃ i x y, z = f x y ∧ l !! i = Some x ∧ k !! i = Some y.
Proof.
naive_solver eauto using
elem_of_lookup_zip_with_1, elem_of_lookup_zip_with_2.
Qed.
Lemma elem_of_zip_with l k (z : C) :
z ∈ zip_with f l k → ∃ x y, z = f x y ∧ x ∈ l ∧ y ∈ k.
Proof.
intros ?%elem_of_lookup_zip_with.
naive_solver eauto using elem_of_list_lookup_2.
Qed.
End zip_with.
Lemma zip_with_diag {A C} (f : A → A → C) l :
zip_with f l l = (λ x, f x x) <$> l.
Proof. induction l as [|?? IH]; [done|]. simpl. rewrite IH. done. Qed.
Section zip.
Context {A B : Type}.
Implicit Types l : list A.
Implicit Types k : list B.
Lemma fst_zip l k : length l ≤ length k → (zip l k).*1 = l.
Proof. by apply fmap_zip_with_l. Qed.
Lemma snd_zip l k : length k ≤ length l → (zip l k).*2 = k.
Proof. by apply fmap_zip_with_r. Qed.
Lemma zip_fst_snd (lk : list (A × B)) : zip (lk.*1) (lk.*2) = lk.
Proof. by induction lk as [|[]]; f_equal/=. Qed.
Lemma Forall2_fst P l1 l2 k1 k2 :
length l2 = length k2 → Forall2 P l1 k1 →
Forall2 (λ x y, P (x.1) (y.1)) (zip l1 l2) (zip k1 k2).
Proof.
rewrite <-Forall2_same_length. intros Hlk2 Hlk1. revert l2 k2 Hlk2.
induction Hlk1; intros ?? [|??????]; simpl; auto.
Qed.
Lemma Forall2_snd P l1 l2 k1 k2 :
length l1 = length k1 → Forall2 P l2 k2 →
Forall2 (λ x y, P (x.2) (y.2)) (zip l1 l2) (zip k1 k2).
Proof.
rewrite <-Forall2_same_length. intros Hlk1 Hlk2. revert l1 k1 Hlk1.
induction Hlk2; intros ?? [|??????]; simpl; auto.
Qed.
Lemma elem_of_zip_l x1 x2 l k :
(x1, x2) ∈ zip l k → x1 ∈ l.
Proof. intros ?%elem_of_zip_with. naive_solver. Qed.
Lemma elem_of_zip_r x1 x2 l k :
(x1, x2) ∈ zip l k → x2 ∈ k.
Proof. intros ?%elem_of_zip_with. naive_solver. Qed.
Lemma length_zip l k :
length (zip l k) = min (length l) (length k).
Proof. by rewrite length_zip_with. Qed.
Lemma zip_nil_inv l k :
zip l k = [] → l = [] ∨ k = [].
Proof. intros. by eapply zip_with_nil_inv. Qed.
Lemma lookup_zip_Some l k i x y :
zip l k !! i = Some (x, y) ↔ l !! i = Some x ∧ k !! i = Some y.
Proof. rewrite lookup_zip_with_Some. naive_solver. Qed.
Lemma lookup_zip_None l k i :
zip l k !! i = None ↔ l !! i = None ∨ k !! i = None.
Proof. by rewrite lookup_zip_with_None. Qed.
End zip.
Lemma zip_diag {A} (l : list A) :
zip l l = (λ x, (x, x)) <$> l.
Proof. apply zip_with_diag. Qed.
Lemma elem_of_zipped_map {A B} (f : list A → list A → A → B) l k x :
x ∈ zipped_map f l k ↔
∃ k' k'' y, k = k' ++ [y] ++ k'' ∧ x = f (reverse k' ++ l) k'' y.
Proof.
split.
- revert l. induction k as [|z k IH]; simpl; intros l; inv 1.
{ by eexists [], k, z. }
destruct (IH (z :: l)) as (k'&k''&y&->&->); [done |].
eexists (z :: k'), k'', y. by rewrite reverse_cons, <-(assoc_L (++)).
- intros (k'&k''&y&->&->). revert l. induction k' as [|z k' IH]; [by left|].
intros l; right. by rewrite reverse_cons, <-!(assoc_L (++)).
Qed.
Section zipped_list_ind.
Context {A} (P : list A → list A → Prop).
Context (Pnil : ∀ l, P l []) (Pcons : ∀ l k x, P (x :: l) k → P l (x :: k)).
Fixpoint zipped_list_ind l k : P l k :=
match k with
| [] ⇒ Pnil _ | x :: k ⇒ Pcons _ _ _ (zipped_list_ind (x :: l) k)
end.
End zipped_list_ind.
Lemma zipped_Forall_app {A} (P : list A → list A → A → Prop) l k k' :
zipped_Forall P l (k ++ k') → zipped_Forall P (reverse k ++ l) k'.
Proof.
revert l. induction k as [|x k IH]; simpl; [done |].
inv 1. rewrite reverse_cons, <-(assoc_L (++)). by apply IH.
Qed.