--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "static_2/syntax/genv.ma".
+
+(* LENGTH OF A GLOBAL ENVIRONMENT *******************************************)
+
+rec definition glength G on G ≝ match G with
+[ GAtom ⇒ 0
+| GPair G _ _ ⇒ ↑(glength G)
+].
+
+interpretation "length (global environment)"
+ 'card G = (glength G).