2 files changed, 15 insertions, 0 deletions
diff --git a/theories/NArith/BinNat.v b/theories/NArith/BinNat.v
index 228be4d1a..418fd8e58 100644
--- a/theories/NArith/BinNat.v
+++ b/theories/NArith/BinNat.v
@@ -442,6 +442,13 @@ Proof.
  now destruct p.
 Qed.
 
+(** Specification of square *)
+
+Lemma square_spec n : square n = n * n.
+Proof.
+ destruct n; trivial. simpl. f_equal. apply Pos.square_spec.
+Qed.
+
 (** Specification of Base-2 logarithm *)
 
 Lemma size_log2 n : n<>0 -> size n = succ (log2 n).
diff --git a/theories/NArith/BinNatDef.v b/theories/NArith/BinNatDef.v
index d459f8509..d7660422a 100644
--- a/theories/NArith/BinNatDef.v
+++ b/theories/NArith/BinNatDef.v
@@ -181,6 +181,14 @@ Definition pow n p :=
 
 Infix "^" := pow : N_scope.
 
+(** Square *)
+
+Definition square n :=
+  match n with
+    | 0 => 0
+    | Npos p => Npos (Pos.square p)
+  end.
+
 (** Base-2 logarithm *)
 
 Definition log2 n :=