--- /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/steps/rtc.ma".
+
+(* RT-TRANSITION COUNTER ****************************************************)
+
+definition plus (r1:rtc) (r2:rtc): rtc ≝ match r1 with [
+ mk_rtc ri1 rh1 ti1 th1 ⇒ match r2 with [
+ mk_rtc ri2 rh2 ti2 th2 ⇒ 〈ri1+ri2, rh1+rh2, ti1+ti2, th1+th2〉
+ ]
+].
+
+interpretation "plus (rtc)"
+ 'plus r1 r2 = (plus r1 r2).