Term Rewriting System R:
[x, y, z]
cons(x, cons(y, z)) -> big
inf(x) -> cons(x, inf(s(x)))
Termination of R to be shown.
R
↳Dependency Pair Analysis
R contains the following Dependency Pairs:
INF(x) -> CONS(x, inf(s(x)))
INF(x) -> INF(s(x))
Furthermore, R contains one SCC.
R
↳DPs
→DP Problem 1
↳Modular Removal of Rules
Dependency Pair:
INF(x) -> INF(s(x))
Rules:
cons(x, cons(y, z)) -> big
inf(x) -> cons(x, inf(s(x)))
We have the following set of usable rules:
none
To remove rules and DPs from this DP problem we used the following monotonic and CE-compatible order: Polynomial ordering.
Polynomial interpretation:
POL(INF(x1)) | = x1 |
POL(s(x1)) | = x1 |
We have the following set D of usable symbols: {INF, s}
No Dependency Pairs can be deleted.
2 non usable rules have been deleted.
The result of this processor delivers one new DP problem.
R
↳DPs
→DP Problem 1
↳MRR
→DP Problem 2
↳Non-Overlappingness Check
Dependency Pair:
INF(x) -> INF(s(x))
Rule:
none
R does not overlap into P. Moreover, R is locally confluent (all critical pairs are trivially joinable).Hence we can switch to innermost.
The transformation is resulting in one subcycle:
R
↳DPs
→DP Problem 1
↳MRR
→DP Problem 2
↳NOC
...
→DP Problem 3
↳Non Termination
Dependency Pair:
INF(x) -> INF(s(x))
Rule:
none
Strategy:
innermost
Found an infinite P-chain over R:
P =
INF(x) -> INF(s(x))
R = none
s = INF(x)
evaluates to t =INF(s(x))
Thus, s starts an infinite chain as s matches t.
Non-Termination of R could be shown.
Duration:
0:01 minutes