Termination w.r.t. Q of the following Term Rewriting System could be disproven:
Q restricted rewrite system:
The TRS R consists of the following rules:
f(s(x)) → f(g(x, x))
g(0, 1) → s(0)
0 → 1
Q is empty.
↳ QTRS
↳ DependencyPairsProof
Q restricted rewrite system:
The TRS R consists of the following rules:
f(s(x)) → f(g(x, x))
g(0, 1) → s(0)
0 → 1
Q is empty.
Using Dependency Pairs [1,15] we result in the following initial DP problem:
Q DP problem:
The TRS P consists of the following rules:
F(s(x)) → F(g(x, x))
F(s(x)) → G(x, x)
The TRS R consists of the following rules:
f(s(x)) → f(g(x, x))
g(0, 1) → s(0)
0 → 1
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
Q DP problem:
The TRS P consists of the following rules:
F(s(x)) → F(g(x, x))
F(s(x)) → G(x, x)
The TRS R consists of the following rules:
f(s(x)) → f(g(x, x))
g(0, 1) → s(0)
0 → 1
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 1 SCC with 1 less node.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ QDP
↳ UsableRulesReductionPairsProof
Q DP problem:
The TRS P consists of the following rules:
F(s(x)) → F(g(x, x))
The TRS R consists of the following rules:
f(s(x)) → f(g(x, x))
g(0, 1) → s(0)
0 → 1
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the usable rules with reduction pair processor [15] with a polynomial ordering [25], all dependency pairs and the corresponding usable rules [17] can be oriented non-strictly. All non-usable rules are removed, and those dependency pairs and usable rules that have been oriented strictly or contain non-usable symbols in their left-hand side are removed as well.
No dependency pairs are removed.
No rules are removed from R.
Used ordering: POLO with Polynomial interpretation [25]:
POL(0) = 0
POL(1) = 0
POL(F(x1)) = x1
POL(g(x1, x2)) = x1 + x2
POL(s(x1)) = 2·x1
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ QDP
↳ UsableRulesReductionPairsProof
↳ QDP
↳ NonTerminationProof
Q DP problem:
The TRS P consists of the following rules:
F(s(x)) → F(g(x, x))
The TRS R consists of the following rules:
g(0, 1) → s(0)
0 → 1
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We used the non-termination processor [17] to show that the DP problem is infinite.
Found a loop by narrowing to the left:
The TRS P consists of the following rules:
F(s(x)) → F(g(x, x))
The TRS R consists of the following rules:
g(0, 1) → s(0)
0 → 1
s = F(g(0, 0)) evaluates to t =F(g(0, 0))
Thus s starts an infinite chain as s semiunifies with t with the following substitutions:
- Semiunifier: [ ]
- Matcher: [ ]
Rewriting sequence
F(g(0, 0)) → F(g(0, 1))
with rule 0 → 1 at position [0,1] and matcher [ ]
F(g(0, 1)) → F(s(0))
with rule g(0, 1) → s(0) at position [0] and matcher [ ]
F(s(0)) → F(g(0, 0))
with rule F(s(x)) → F(g(x, x))
Now applying the matcher to the start term leads to a term which is equal to the last term in the rewriting sequence
All these steps are and every following step will be a correct step w.r.t to Q.