--- /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 "basic_2/relocation/lexs_length.ma".
+include "basic_2/relocation/lreq.ma".
+
+(* RANGED EQUIVALENCE FOR LOCAL ENVIRONMENTS ********************************)
+
+(* Forward lemmas on length for local environments **************************)
+
+(* Basic_2A1: includes: lreq_fwd_length *)
+lemma lreq_fwd_length: ∀L1,L2,f. L1 ≡[f] L2 → |L1| = |L2|.
+/2 width=4 by lexs_fwd_length/ qed-.