+(**************************************************************************)
+(* ___ *)
+(* ||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 "basic_2/syntax/term_weight.ma".
+include "basic_2/syntax/genv.ma".
+
+(* WEIGHT OF A GLOBAL ENVIRONMENT *******************************************)
+
+rec definition gw G ≝ match G with
+[ GAtom ⇒ 0
+| GPair G I T ⇒ gw G + ♯{T}
+].
+
+interpretation "weight (global environment)" 'Weight G = (gw G).
+
+(* Basic properties *********************************************************)
+
+lemma gw_pair: ∀I,G,T. ♯{G} < ♯{G.ⓑ{I}T}.
+normalize /2 width=1 by monotonic_le_plus_r/ qed.