(0) Obligation:
Q restricted rewrite system:
The TRS R consists of the following rules:
a(x) → b(c(x))
a(c(b(x))) → b(a(a(c(x))))
b(b(x)) → x
Q is empty.
(1) DependencyPairsProof (EQUIVALENT transformation)
Using Dependency Pairs [AG00,LPAR04] we result in the following initial DP problem.
(2) Obligation:
Q DP problem:
The TRS P consists of the following rules:
A(x) → B(c(x))
A(c(b(x))) → B(a(a(c(x))))
A(c(b(x))) → A(a(c(x)))
A(c(b(x))) → A(c(x))
The TRS R consists of the following rules:
a(x) → b(c(x))
a(c(b(x))) → b(a(a(c(x))))
b(b(x)) → x
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
(3) DependencyGraphProof (EQUIVALENT transformation)
The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 1 SCC with 2 less nodes.
(4) Obligation:
Q DP problem:
The TRS P consists of the following rules:
A(c(b(x))) → A(c(x))
A(c(b(x))) → A(a(c(x)))
The TRS R consists of the following rules:
a(x) → b(c(x))
a(c(b(x))) → b(a(a(c(x))))
b(b(x)) → x
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
(5) QDPOrderProof (EQUIVALENT transformation)
We use the reduction pair processor [LPAR04,JAR06].
The following pairs can be oriented strictly and are deleted.
A(c(b(x))) → A(c(x))
A(c(b(x))) → A(a(c(x)))
The remaining pairs can at least be oriented weakly.
Used ordering: Matrix interpretation [MATRO] with arctic natural numbers [ARCTIC]:
| POL(c(x1)) = | | + | | / | 0A | -I | 0A | \ |
| | | 0A | -I | 1A | | |
| \ | -I | -I | -I | / |
| · | x1 |
| POL(b(x1)) = | | + | | / | -I | 0A | 0A | \ |
| | | 0A | -I | 0A | | |
| \ | 0A | -I | 1A | / |
| · | x1 |
| POL(a(x1)) = | | + | | / | 0A | -I | 1A | \ |
| | | 0A | 0A | 0A | | |
| \ | 0A | 0A | 0A | / |
| · | x1 |
The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:
a(x) → b(c(x))
a(c(b(x))) → b(a(a(c(x))))
b(b(x)) → x
(6) Obligation:
Q DP problem:
P is empty.
The TRS R consists of the following rules:
a(x) → b(c(x))
a(c(b(x))) → b(a(a(c(x))))
b(b(x)) → x
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
(7) PisEmptyProof (EQUIVALENT transformation)
The TRS P is empty. Hence, there is no (P,Q,R) chain.
(8) YES