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:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
↳ QTRS
↳ DependencyPairsProof
Q restricted rewrite system:
The TRS R consists of the following rules:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
Using Dependency Pairs [1,15] we result in the following initial DP problem:
Q DP problem:
The TRS P consists of the following rules:
*1(+(x, y), z) → *1(x, z)
*1(*(x, y), z) → *1(y, z)
*1(x, +(y, f(z))) → *1(g(x, z), +(y, y))
*1(*(x, y), z) → *1(x, *(y, z))
*1(+(x, y), z) → *1(y, z)
The TRS R consists of the following rules:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
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:
*1(+(x, y), z) → *1(x, z)
*1(*(x, y), z) → *1(y, z)
*1(x, +(y, f(z))) → *1(g(x, z), +(y, y))
*1(*(x, y), z) → *1(x, *(y, z))
*1(+(x, y), z) → *1(y, z)
The TRS R consists of the following rules:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
We have to consider all minimal (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 2 SCCs with 1 less node.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ UsableRulesProof
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(x, +(y, f(z))) → *1(g(x, z), +(y, y))
The TRS R consists of the following rules:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
We have to consider all minimal (P,Q,R)-chains.
As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [15] we can delete all non-usable rules [17] from R.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ UsableRulesProof
↳ QDP
↳ QReductionProof
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(x, +(y, f(z))) → *1(g(x, z), +(y, y))
R is empty.
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
We have to consider all minimal (P,Q,R)-chains.
We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ UsableRulesProof
↳ QDP
↳ QReductionProof
↳ QDP
↳ Instantiation
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(x, +(y, f(z))) → *1(g(x, z), +(y, y))
R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By instantiating [15] the rule *1(x, +(y, f(z))) → *1(g(x, z), +(y, y)) we obtained the following new rules:
*1(g(z0, z2), +(f(x2), f(x2))) → *1(g(g(z0, z2), x2), +(f(x2), f(x2)))
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ UsableRulesProof
↳ QDP
↳ QReductionProof
↳ QDP
↳ Instantiation
↳ QDP
↳ Instantiation
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(g(z0, z2), +(f(x2), f(x2))) → *1(g(g(z0, z2), x2), +(f(x2), f(x2)))
R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By instantiating [15] the rule *1(g(z0, z2), +(f(x2), f(x2))) → *1(g(g(z0, z2), x2), +(f(x2), f(x2))) we obtained the following new rules:
*1(g(g(z0, z1), z2), +(f(z2), f(z2))) → *1(g(g(g(z0, z1), z2), z2), +(f(z2), f(z2)))
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ UsableRulesProof
↳ QDP
↳ QReductionProof
↳ QDP
↳ Instantiation
↳ QDP
↳ Instantiation
↳ QDP
↳ NonTerminationProof
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(g(g(z0, z1), z2), +(f(z2), f(z2))) → *1(g(g(g(z0, z1), z2), z2), +(f(z2), f(z2)))
R is empty.
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 semiunifying a rule from P directly.
The TRS P consists of the following rules:
*1(g(g(z0, z1), z2), +(f(z2), f(z2))) → *1(g(g(g(z0, z1), z2), z2), +(f(z2), f(z2)))
The TRS R consists of the following rules:none
s = *1(g(g(z0, z1), z2), +(f(z2), f(z2))) evaluates to t =*1(g(g(g(z0, z1), z2), z2), +(f(z2), f(z2)))
Thus s starts an infinite chain as s semiunifies with t with the following substitutions:
- Semiunifier: [ ]
- Matcher: [z1 / z2, z0 / g(z0, z1)]
Rewriting sequence
The DP semiunifies directly so there is only one rewrite step from *^1(g(g(z0, z1), z2), +(f(z2), f(z2))) to *^1(g(g(g(z0, z1), z2), z2), +(f(z2), f(z2))).
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ QDP
↳ UsableRulesProof
Q DP problem:
The TRS P consists of the following rules:
*1(+(x, y), z) → *1(x, z)
*1(*(x, y), z) → *1(y, z)
*1(+(x, y), z) → *1(y, z)
The TRS R consists of the following rules:
*(*(x, y), z) → *(x, *(y, z))
*(+(x, y), z) → +(*(x, z), *(y, z))
*(x, +(y, f(z))) → *(g(x, z), +(y, y))
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
We have to consider all minimal (P,Q,R)-chains.
As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [15] we can delete all non-usable rules [17] from R.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ QDP
↳ UsableRulesProof
↳ QDP
↳ QDPSizeChangeProof
Q DP problem:
The TRS P consists of the following rules:
*1(+(x, y), z) → *1(x, z)
*1(*(x, y), z) → *1(y, z)
*1(+(x, y), z) → *1(y, z)
R is empty.
The set Q consists of the following terms:
*(x0, +(x1, f(x2)))
*(*(x0, x1), x2)
*(+(x0, x1), x2)
We have to consider all minimal (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem. From the DPs we obtained the following set of size-change graphs:
- *1(+(x, y), z) → *1(x, z)
The graph contains the following edges 1 > 1, 2 >= 2
- *1(*(x, y), z) → *1(y, z)
The graph contains the following edges 1 > 1, 2 >= 2
- *1(+(x, y), z) → *1(y, z)
The graph contains the following edges 1 > 1, 2 >= 2