(0) Obligation:
Q restricted rewrite system:
The TRS R consists of the following rules:
d(a(x)) → b(d(x))
b(x) → a(a(a(x)))
c(d(c(x))) → a(d(x))
b(d(d(x))) → c(c(d(d(c(x)))))
Q is empty.
 
(1) QTRS Reverse (EQUIVALENT transformation)
We applied the QTRS Reverse Processor [REVERSE].
(2) Obligation:
Q restricted rewrite system:
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(x)))))
Q is empty.
 
(3) DependencyPairsProof (EQUIVALENT transformation)
Using Dependency Pairs [AG00,LPAR04] we result in the following initial DP problem.
(4) Obligation:
Q DP problem:
The TRS P consists of the following rules:
A(d(x)) → D(b(x))
A(d(x)) → B(x)
B(x) → A(a(a(x)))
B(x) → A(a(x))
B(x) → A(x)
C(d(c(x))) → D(a(x))
C(d(c(x))) → A(x)
D(d(b(x))) → C(d(d(c(c(x)))))
D(d(b(x))) → D(d(c(c(x))))
D(d(b(x))) → D(c(c(x)))
D(d(b(x))) → C(c(x))
D(d(b(x))) → C(x)
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(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(d(x)) → B(x)
C(d(c(x))) → A(x)
D(d(b(x))) → D(c(c(x)))
D(d(b(x))) → C(c(x))
D(d(b(x))) → C(x)
The remaining pairs can at least be oriented weakly.
Used ordering:  Polynomial interpretation [POLO]:
POL(A(x1)) = x1   
POL(B(x1)) = x1   
POL(C(x1)) = x1   
POL(D(x1)) = 1 + x1   
POL(a(x1)) = x1   
POL(b(x1)) = x1   
POL(c(x1)) = x1   
POL(d(x1)) = 1 + x1   
The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:
b(x) → a(a(a(x)))
a(d(x)) → d(b(x))
d(d(b(x))) → c(d(d(c(c(x)))))
c(d(c(x))) → d(a(x))
 
(6) Obligation:
Q DP problem:
The TRS P consists of the following rules:
A(d(x)) → D(b(x))
B(x) → A(a(a(x)))
B(x) → A(a(x))
B(x) → A(x)
C(d(c(x))) → D(a(x))
D(d(b(x))) → C(d(d(c(c(x)))))
D(d(b(x))) → D(d(c(c(x))))
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(x)))))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
 
(7) DependencyGraphProof (EQUIVALENT transformation)
The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 1 SCC with 4 less nodes.
(8) Obligation:
Q DP problem:
The TRS P consists of the following rules:
D(d(b(x))) → C(d(d(c(c(x)))))
C(d(c(x))) → D(a(x))
D(d(b(x))) → D(d(c(c(x))))
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(x)))))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
 
(9) QDPOrderProof (EQUIVALENT transformation)
We use the reduction pair processor [LPAR04,JAR06].
The following pairs can be oriented strictly and are deleted.
D(d(b(x))) → D(d(c(c(x))))
The remaining pairs can at least be oriented weakly.
Used ordering:  Polynomial Order [NEGPOLO,POLO] with Interpretation:
| POL( D(x1) ) = max{0, 2x1 - 1} | 
| POL( d(x1) ) = max{0, x1 - 1} | 
| POL( c(x1) ) = max{0, -2} | 
The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:
d(d(b(x))) → c(d(d(c(c(x)))))
c(d(c(x))) → d(a(x))
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
 
(10) Obligation:
Q DP problem:
The TRS P consists of the following rules:
D(d(b(x))) → C(d(d(c(c(x)))))
C(d(c(x))) → D(a(x))
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(x)))))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
 
(11) QDPOrderProof (EQUIVALENT transformation)
We use the reduction pair processor [LPAR04,JAR06].
The following pairs can be oriented strictly and are deleted.
C(d(c(x))) → D(a(x))
The remaining pairs can at least be oriented weakly.
Used ordering:  Matrix interpretation [MATRO] with arctic natural numbers [ARCTIC]:
| POL(d(x1)) =  |  |  +  | | / | -I | 0A | 0A | \ |  
| | | 1A | -I | 0A | | |  
| \ | 0A | 0A | 1A | / |  
  | · | x1 | 
| POL(b(x1)) =  |  |  +  | | / | 0A | 0A | 1A | \ |  
| | | 0A | 0A | 1A | | |  
| \ | -I | -I | 0A | / |  
  | · | x1 | 
| POL(c(x1)) =  |  |  +  | | / | 0A | 0A | 0A | \ |  
| | | -I | -I | 0A | | |  
| \ | -I | -I | 0A | / |  
  | · | x1 | 
| POL(a(x1)) =  |  |  +  | | / | -I | -I | 0A | \ |  
| | | 0A | 0A | 1A | | |  
| \ | -I | -I | 0A | / |  
  | · | x1 | 
The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:
d(d(b(x))) → c(d(d(c(c(x)))))
c(d(c(x))) → d(a(x))
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
 
(12) Obligation:
Q DP problem:
The TRS P consists of the following rules:
D(d(b(x))) → C(d(d(c(c(x)))))
The TRS R consists of the following rules:
a(d(x)) → d(b(x))
b(x) → a(a(a(x)))
c(d(c(x))) → d(a(x))
d(d(b(x))) → c(d(d(c(c(x)))))
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
 
(13) DependencyGraphProof (EQUIVALENT transformation)
The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 1 less node.
(14) TRUE