--- /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/notation/relations/ist_2.ma".
+include "ground/counters/rtc.ma".
+
+(* T-TRANSITION COUNTERS ****************************************************)
+
+definition rtc_ist: relation2 nat rtc ≝
+ λts,c. 〈𝟎,𝟎,𝟎,ts〉 = c.
+
+interpretation
+ "t-transition counters (rtc)"
+ 'IsT ts c = (rtc_ist ts c).
+
+(* Basic constructions ******************************************************)
+
+lemma rtc_ist_zz: 𝐓❪𝟎,𝟘𝟘❫.
+// qed.
+
+lemma rtc_ist_zu: 𝐓❪𝟏,𝟘𝟙❫.
+// qed.
+
+(* Basic inversions *********************************************************)
+
+lemma rtc_ist_inv_zz (n): 𝐓❪n,𝟘𝟘❫ → 𝟎 = n.
+#n #H destruct //
+qed-.
+
+lemma rtc_ist_inv_zu (n): 𝐓❪n,𝟘𝟙❫ → ninj (𝟏) = n.
+#n #H destruct //
+qed-.
+
+lemma rtc_ist_inv_uz (n): 𝐓❪n,𝟙𝟘❫ → ⊥.
+#h #H destruct
+qed-.
+
+(* Main inversions **********************************************************)
+
+theorem rtc_ist_inj (n1) (n2) (c): 𝐓❪n1,c❫ → 𝐓❪n2,c❫ → n1 = n2.
+#n1 #n2 #c #H1 #H2 destruct //
+qed-.
+
+theorem rtc_ist_mono (n) (c1) (c2): 𝐓❪n,c1❫ → 𝐓❪n,c2❫ → c1 = c2.
+#n #c1 #c2 #H1 #H2 destruct //
+qed-.