Library mathcomp.ssreflect.ssrfun

From mathcomp Require Import ssreflect.
From Coq Require Export ssrfun.
From mathcomp Require Export ssrnotations.

Definition injective2 (rT aT1 aT2 : Type) (f : aT1 → aT2 → rT) :=
  ∀ (x1 x2 : aT1) (y1 y2 : aT2), f x1 y1 = f x2 y2 → (x1 = x2) × (y1 = y2).

Arguments injective2 [rT aT1 aT2] f.

v8.17 additions oflit f := Some \o f

Set Implicit Arguments.

Definition olift aT rT (f : aT → rT) := Some \o f.

Lemma obindEapp {aT rT} (f : aT → option rT) : obind f = oapp f None.

Lemma omapEbind {aT rT} (f : aT → rT) : omap f = obind (olift f).

Lemma omapEapp {aT rT} (f : aT → rT) : omap f = oapp (olift f) None.

Lemma oappEmap {aT rT} (f : aT → rT) (y0 : rT) x :
  oapp f y0 x = odflt y0 (omap f x).

Lemma omap_comp aT rT sT (f : aT → rT) (g : rT → sT) :
  omap (g \o f) =1 omap g \o omap f.

Lemma oapp_comp aT rT sT (f : aT → rT) (g : rT → sT) x :
  oapp (g \o f) x =1 (@oapp _ _)^~ x g \o omap f.

Lemma oapp_comp_f {aT rT sT} (f : aT → rT) (g : rT → sT) (x : rT) :
  oapp (g \o f) (g x) =1 g \o oapp f x.

Lemma olift_comp aT rT sT (f : aT → rT) (g : rT → sT) :
  olift (g \o f) = olift g \o f.

Lemma compA {A B C D : Type} (f : B → A) (g : C → B) (h : D → C) :
  f \o (g \o h) = (f \o g) \o h.

Lemma ocan_comp [A B C : Type] [f : B → option A] [h : C → option B]
    [f' : A → B] [h' : B → C] :
  ocancel f f' → ocancel h h' → ocancel (obind f \o h) (h' \o f').

v8.18 additions

Notation sval := (@proj1_sig _ _).

not yet backported

Lemma inj_omap {aT rT : Type} (f : aT → rT) :
  injective f → injective (omap f).

Lemma omap_id {T : Type} (x : option T) : omap id x = x.

Lemma eq_omap {aT rT : Type} (f g : aT → rT) : f =1 g → omap f =1 omap g.

Lemma omapK {aT rT : Type} (f : aT → rT) (g : rT → aT) :
  cancel f g → cancel (omap f) (omap g).

The notations below are already defined in Coq.ssr.ssrfun, but we redefine them in different notation scopes (mostly fun_scope -> function_scope, in order to replace the former with the latter).

Open Scope function_scope.

Notation "f ^~ y" := (fun x ⇒ f x y) : function_scope.
Notation "@^~ x" := (fun f ⇒ f x) : function_scope.

Notation "[ 'fun' : T => E ]" := (SimplFun (fun _ : T ⇒ E)) : function_scope.
Notation "[ 'fun' x => E ]" := (SimplFun (fun x ⇒ E)) : function_scope.
Notation "[ 'fun' x y => E ]" := (fun x ⇒ [fun y ⇒ E]) : function_scope.
Notation "[ 'fun' x : T => E ]" := (SimplFun (fun x : T ⇒ E))
  (only parsing) : function_scope.
Notation "[ 'fun' x y : T => E ]" := (fun x : T ⇒ [fun y : T ⇒ E])
  (only parsing) : function_scope.
Notation "[ 'fun' ( x : T ) y => E ]" := (fun x : T ⇒ [fun y ⇒ E])
  (only parsing) : function_scope.
Notation "[ 'fun' x ( y : T ) => E ]" := (fun x ⇒ [fun y : T ⇒ E])
  (only parsing) : function_scope.
Notation "[ 'fun' ( x : T ) ( y : U ) => E ]" := (fun x : T ⇒ [fun y : U ⇒ E])
  (only parsing) : function_scope.

Notation "f1 =1 f2" := (eqfun f1 f2) : type_scope.
Notation "f1 =1 f2 :> A" := (f1 =1 (f2 : A)) : type_scope.
Notation "f1 =2 f2" := (eqrel f1 f2) : type_scope.
Notation "f1 =2 f2 :> A" := (f1 =2 (f2 : A)) : type_scope.

Notation "f1 \o f2" := (comp f1 f2) : function_scope.
Notation "f1 \; f2" := (catcomp f1 f2) : function_scope.

Notation "[ 'eta' f ]" := (fun x ⇒ f x) : function_scope.

Notation "'fun' => E" := (fun _ ⇒ E) : function_scope.

Notation "@ 'id' T" := (fun x : T ⇒ x)
  (at level 10, T at level 8, only parsing) : function_scope.

Notation "@ 'sval'" := (@proj1_sig) (at level 10, only parsing) :
  function_scope.