Term Rewriting System R:
[X, Y, Z, X1]
2nd(cons1(X, cons(Y, Z))) -> Y
2nd(cons(X, X1)) -> 2nd(cons1(X, X1))
from(X) -> cons(X, from(s(X)))

Termination of R to be shown. 



   R
     ↳Overlay and local confluence Check



The TRS is overlay and locally confluent (all critical pairs are trivially joinable).Hence, we can switch to innermost. 


   R
     ↳OC
       →TRS2
         ↳Dependency Pair Analysis



R contains the following Dependency Pairs:

2ND(cons(X, X1)) -> 2ND(cons1(X, X1))
FROM(X) -> FROM(s(X))

Furthermore, R contains one SCC. 


   R
     ↳OC
       →TRS2
         ↳DPs
           →DP Problem 1
             ↳Usable Rules (Innermost)


Dependency Pair:

FROM(X) -> FROM(s(X))


Rules:


2nd(cons1(X, cons(Y, Z))) -> Y
2nd(cons(X, X1)) -> 2nd(cons1(X, X1))
from(X) -> cons(X, from(s(X)))


Strategy:

innermost




As we are in the innermost case, we can delete all 3 non-usable-rules.


   R
     ↳OC
       →TRS2
         ↳DPs
           →DP Problem 1
             ↳UsableRules
             ...
               →DP Problem 2
                 ↳Non Termination


Dependency Pair:

FROM(X) -> FROM(s(X))


Rule:

none


Strategy:

innermost




Found an infinite P-chain over R:
P =

FROM(X) -> FROM(s(X))

R = none

s = FROM(X)
evaluates to t =FROM(s(X))

Thus, s starts an infinite chain as s matches t.

Non-Termination of R could be shown.
Duration:
0:02 minutes