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-rw-r--r--theories/Arith/Between.v14
1 files changed, 10 insertions, 4 deletions
diff --git a/theories/Arith/Between.v b/theories/Arith/Between.v
index 9b4071085..25d84a621 100644
--- a/theories/Arith/Between.v
+++ b/theories/Arith/Between.v
@@ -1,9 +1,11 @@
(************************************************************************)
-(* v * The Coq Proof Assistant / The Coq Development Team *)
-(* <O___,, * INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2017 *)
+(* * The Coq Proof Assistant / The Coq Development Team *)
+(* v * INRIA, CNRS and contributors - Copyright 1999-2018 *)
+(* <O___,, * (see CREDITS file for the list of authors) *)
(* \VV/ **************************************************************)
-(* // * This file is distributed under the terms of the *)
-(* * GNU Lesser General Public License Version 2.1 *)
+(* // * This file is distributed under the terms of the *)
+(* * GNU Lesser General Public License Version 2.1 *)
+(* * (see LICENSE file for the text of the license) *)
(************************************************************************)
Require Import Le.
@@ -16,6 +18,8 @@ Implicit Types k l p q r : nat.
Section Between.
Variables P Q : nat -> Prop.
+ (** The [between] type expresses the concept
+ [forall i: nat, k <= i < l -> P i.]. *)
Inductive between k : nat -> Prop :=
| bet_emp : between k k
| bet_S : forall l, between k l -> P l -> between k (S l).
@@ -47,6 +51,8 @@ Section Between.
induction 1; auto with arith.
Qed.
+ (** The [exists_between] type expresses the concept
+ [exists i: nat, k <= i < l /\ Q i]. *)
Inductive exists_between k : nat -> Prop :=
| exists_S : forall l, exists_between k l -> exists_between k (S l)
| exists_le : forall l, k <= l -> Q l -> exists_between k (S l).