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))
Q is empty.
↳ 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))
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:
*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))
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:
*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))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 2 SCCs.
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ 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))
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))
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(y_0, y_1), +(y_2, f(x2))) → *1(g(g(y_0, y_1), x2), +(y_2, y_2))
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ Instantiation
↳ QDP
↳ Instantiation
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(g(y_0, y_1), +(y_2, f(x2))) → *1(g(g(y_0, y_1), x2), +(y_2, y_2))
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))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By instantiating [15] the rule *1(g(y_0, y_1), +(y_2, f(x2))) → *1(g(g(y_0, y_1), x2), +(y_2, y_2)) we obtained the following new rules:
*1(g(g(y_0, y_1), y_2), +(y_3, f(x3))) → *1(g(g(g(y_0, y_1), y_2), x3), +(y_3, y_3))
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ Instantiation
↳ QDP
↳ Instantiation
↳ QDP
↳ ForwardInstantiation
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(g(g(y_0, y_1), y_2), +(y_3, f(x3))) → *1(g(g(g(y_0, y_1), y_2), x3), +(y_3, y_3))
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))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By forward instantiating [14] the rule *1(g(g(y_0, y_1), y_2), +(y_3, f(x3))) → *1(g(g(g(y_0, y_1), y_2), x3), +(y_3, y_3)) we obtained the following new rules:
*1(g(g(x0, x1), x2), +(f(y_4), f(x4))) → *1(g(g(g(x0, x1), x2), x4), +(f(y_4), f(y_4)))
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ Instantiation
↳ QDP
↳ Instantiation
↳ QDP
↳ ForwardInstantiation
↳ QDP
↳ NonTerminationProof
↳ QDP
Q DP problem:
The TRS P consists of the following rules:
*1(g(g(x0, x1), x2), +(f(y_4), f(x4))) → *1(g(g(g(x0, x1), x2), x4), +(f(y_4), f(y_4)))
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))
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(x0, x1), x2), +(f(y_4), f(x4))) → *1(g(g(g(x0, x1), x2), x4), +(f(y_4), f(y_4)))
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))
s = *1(g(g(x0, x1), x2), +(f(y_4), f(x4))) evaluates to t =*1(g(g(g(x0, x1), x2), x4), +(f(y_4), f(y_4)))
Thus s starts an infinite chain as s semiunifies with t with the following substitutions:
- Semiunifier: [ ]
- Matcher: [x0 / g(x0, x1), x1 / x2, x2 / x4, x4 / y_4]
Rewriting sequence
The DP semiunifies directly so there is only one rewrite step from *^1(g(g(x0, x1), x2), +(f(y_4), f(x4))) to *^1(g(g(g(x0, x1), x2), x4), +(f(y_4), f(y_4))).
↳ QTRS
↳ DependencyPairsProof
↳ QDP
↳ DependencyGraphProof
↳ AND
↳ QDP
↳ 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(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))
Q is empty.
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(y, z)
The graph contains the following edges 1 > 1, 2 >= 2
- *1(*(x, y), z) → *1(x, *(y, z))
The graph contains the following edges 1 > 1
- *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