--- /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 "ground_2/relocation/mr2.ma".
+
+(* MULTIPLE RELOCATION WITH PAIRS *******************************************)
+
+let rec pluss (cs:mr2) (i:nat) on cs ≝ match cs with
+[ nil2 ⇒ ◊
+| cons2 l m cs ⇒ {l + i, m} @ pluss cs i
+].
+
+interpretation "plus (multiple relocation with pairs)"
+ 'plus x y = (pluss x y).
+
+(* Basic properties *********************************************************)
+
+lemma pluss_SO2: ∀l,m,cs. ({l, m} @ cs) + 1 = {⫯l, m} @ cs + 1.
+normalize // qed.
+
+(* Basic inversion lemmas ***************************************************)
+
+lemma pluss_inv_nil2: ∀i,cs. cs + i = ◊ → cs = ◊.
+#i * // normalize
+#l #m #cs #H destruct
+qed.
+
+lemma pluss_inv_cons2: ∀i,l,m,cs2,cs. cs + i = {l, m} @ cs2 →
+ ∃∃cs1. cs1 + i = cs2 & cs = {l - i, m} @ cs1.
+#i #l #m #cs2 *
+[ normalize #H destruct
+| #l1 #m1 #cs1 whd in ⊢ (??%?→?); #H destruct
+ <minus_plus_m_m /2 width=3 by ex2_intro/
+]
+qed-.