Termination w.r.t. Q of the following Term Rewriting System could not be shown:

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

Q is empty.


QTRS
  ↳ DependencyPairsProof
  ↳ QTRS Reverse

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

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:

C(b(x1)) → A(x1)
A(a(b(x1))) → A(x1)
C(b(x1)) → C(a(x1))
A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.

↳ QTRS
  ↳ DependencyPairsProof
QDP
      ↳ DependencyGraphProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

C(b(x1)) → A(x1)
A(a(b(x1))) → A(x1)
C(b(x1)) → C(a(x1))
A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

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 with 1 less node.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

A(a(b(x1))) → A(x1)
A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We can use the usable rules and reduction pair processor [15] with the Ce-compatible extension of the polynomial order that maps every function symbol to the sum of its argument. Then, we can delete all non-usable rules [17] from R.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
            ↳ UsableRulesProof
QDP
            ↳ UsableRulesProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

A(a(b(x1))) → A(x1)
A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We can use the usable rules and reduction pair processor [15] with the Ce-compatible extension of the polynomial order that maps every function symbol to the sum of its argument. Then, we can delete all non-usable rules [17] from R.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
QDP
                ↳ RuleRemovalProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

A(a(b(x1))) → A(x1)
A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the rule removal processor [15] with the following polynomial ordering [25], at least one Dependency Pair or term rewrite system rule of this QDP problem can be strictly oriented.
Strictly oriented dependency pairs:

A(a(b(x1))) → A(x1)

Strictly oriented rules of the TRS R:

a(x1) → x1

Used ordering: POLO with Polynomial interpretation [25]:

POL(A(x1)) = 2·x1   
POL(a(x1)) = 2 + 2·x1   
POL(b(x1)) = x1   



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
              ↳ QDP
                ↳ RuleRemovalProof
QDP
                    ↳ MNOCProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We use the modular non-overlap check [15] to enlarge Q to all left-hand sides of R.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
              ↳ QDP
                ↳ RuleRemovalProof
                  ↳ QDP
                    ↳ MNOCProof
QDP
                        ↳ RuleRemovalProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

A(a(b(x1))) → A(a(x1))

The TRS R consists of the following rules:

a(a(b(x1))) → b(b(a(a(x1))))

The set Q consists of the following terms:

a(a(b(x0)))

We have to consider all minimal (P,Q,R)-chains.
By using the rule removal processor [15] with the following polynomial ordering [25], at least one Dependency Pair or term rewrite system rule of this QDP problem can be strictly oriented.
Strictly oriented dependency pairs:

A(a(b(x1))) → A(a(x1))

Strictly oriented rules of the TRS R:

a(a(b(x1))) → b(b(a(a(x1))))

Used ordering: POLO with Polynomial interpretation [25]:

POL(A(x1)) = x1   
POL(a(x1)) = 2·x1   
POL(b(x1)) = 1 + x1   



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
              ↳ QDP
                ↳ RuleRemovalProof
                  ↳ QDP
                    ↳ MNOCProof
                      ↳ QDP
                        ↳ RuleRemovalProof
QDP
                            ↳ PisEmptyProof
          ↳ QDP
  ↳ QTRS Reverse

Q DP problem:
P is empty.
R is empty.
The set Q consists of the following terms:

a(a(b(x0)))

We have to consider all minimal (P,Q,R)-chains.
The TRS P is empty. Hence, there is no (P,Q,R) chain.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

C(b(x1)) → C(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We can use the usable rules and reduction pair processor [15] with the Ce-compatible extension of the polynomial order that maps every function symbol to the sum of its argument. Then, we can delete all non-usable rules [17] from R.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
QDP
                ↳ Narrowing
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

C(b(x1)) → C(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By narrowing [15] the rule C(b(x1)) → C(a(x1)) at position [0] we obtained the following new rules:

C(b(a(b(x0)))) → C(b(b(a(a(x0)))))
C(b(x0)) → C(x0)



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
QDP
                    ↳ QDPToSRSProof
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

C(b(a(b(x0)))) → C(b(b(a(a(x0)))))
C(b(x0)) → C(x0)

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The finiteness of this DP problem is implied by strong termination of a SRS due to [12].


↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
QTRS
                        ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
C(b(a(b(x0)))) → C(b(b(a(a(x0)))))
C(b(x0)) → C(x0)

Q is empty.

We have reversed the following QTRS:
The set of rules R is

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
C(b(a(b(x0)))) → C(b(b(a(a(x0)))))
C(b(x0)) → C(x0)

The set Q is empty.
We have obtained the following QTRS:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

The set Q is empty.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

Q is empty.

We have reversed the following QTRS:
The set of rules R is

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

The set Q is empty.
We have obtained the following QTRS:

a(x) → x
a(a(b(x))) → b(b(a(a(x))))
C(b(a(b(x)))) → C(b(b(a(a(x)))))
C(b(x)) → C(x)

The set Q is empty.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
QTRS
                            ↳ DependencyPairsProof
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x) → x
a(a(b(x))) → b(b(a(a(x))))
C(b(a(b(x)))) → C(b(b(a(a(x)))))
C(b(x)) → C(x)

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:

B(a(a(x))) → A(a(b(b(x))))
B(a(b(C(x)))) → A(b(b(C(x))))
B(a(a(x))) → A(b(b(x)))
B(a(b(C(x)))) → A(a(b(b(C(x)))))
B(a(a(x))) → B(x)
B(a(b(C(x)))) → B(b(C(x)))
B(a(a(x))) → B(b(x))

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
QDP
                                ↳ DependencyGraphProof
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(a(x))) → A(a(b(b(x))))
B(a(b(C(x)))) → A(b(b(C(x))))
B(a(a(x))) → A(b(b(x)))
B(a(b(C(x)))) → A(a(b(b(C(x)))))
B(a(a(x))) → B(x)
B(a(b(C(x)))) → B(b(C(x)))
B(a(a(x))) → B(b(x))

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

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 4 less nodes.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
QDP
                                    ↳ Narrowing
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(a(x))) → B(x)
B(a(b(C(x)))) → B(b(C(x)))
B(a(a(x))) → B(b(x))

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By narrowing [15] the rule B(a(b(C(x)))) → B(b(C(x))) at position [0] we obtained the following new rules:

B(a(b(C(x0)))) → B(C(x0))



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
                                  ↳ QDP
                                    ↳ Narrowing
QDP
                                        ↳ DependencyGraphProof
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(b(C(x0)))) → B(C(x0))
B(a(a(x))) → B(x)
B(a(a(x))) → B(b(x))

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

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
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
                                  ↳ QDP
                                    ↳ Narrowing
                                      ↳ QDP
                                        ↳ DependencyGraphProof
QDP
                                            ↳ Narrowing
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(a(x))) → B(x)
B(a(a(x))) → B(b(x))

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By narrowing [15] the rule B(a(a(x))) → B(b(x)) at position [0] we obtained the following new rules:

B(a(a(a(a(x0))))) → B(a(a(b(b(x0)))))
B(a(a(C(x0)))) → B(C(x0))
B(a(a(a(b(C(x0)))))) → B(a(a(b(b(C(x0))))))



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
                                  ↳ QDP
                                    ↳ Narrowing
                                      ↳ QDP
                                        ↳ DependencyGraphProof
                                          ↳ QDP
                                            ↳ Narrowing
QDP
                                                ↳ DependencyGraphProof
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(a(a(a(x0))))) → B(a(a(b(b(x0)))))
B(a(a(C(x0)))) → B(C(x0))
B(a(a(a(b(C(x0)))))) → B(a(a(b(b(C(x0))))))
B(a(a(x))) → B(x)

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

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
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
                                  ↳ QDP
                                    ↳ Narrowing
                                      ↳ QDP
                                        ↳ DependencyGraphProof
                                          ↳ QDP
                                            ↳ Narrowing
                                              ↳ QDP
                                                ↳ DependencyGraphProof
QDP
                            ↳ QTRS Reverse
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

B(a(a(a(a(x0))))) → B(a(a(b(b(x0)))))
B(a(a(a(b(C(x0)))))) → B(a(a(b(b(C(x0))))))
B(a(a(x))) → B(x)

The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We have reversed the following QTRS:
The set of rules R is

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(a(b(C(x)))) → a(a(b(b(C(x)))))
b(C(x)) → C(x)

The set Q is empty.
We have obtained the following QTRS:

a(x) → x
a(a(b(x))) → b(b(a(a(x))))
C(b(a(b(x)))) → C(b(b(a(a(x)))))
C(b(x)) → C(x)

The set Q is empty.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
              ↳ QDP
                ↳ Narrowing
                  ↳ QDP
                    ↳ QDPToSRSProof
                      ↳ QTRS
                        ↳ QTRS Reverse
                          ↳ QTRS
                            ↳ QTRS Reverse
                            ↳ DependencyPairsProof
                            ↳ QTRS Reverse
QTRS
            ↳ UsableRulesProof
  ↳ QTRS Reverse

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x) → x
a(a(b(x))) → b(b(a(a(x))))
C(b(a(b(x)))) → C(b(b(a(a(x)))))
C(b(x)) → C(x)

Q is empty.

We can use the usable rules and reduction pair processor [15] with the Ce-compatible extension of the polynomial order that maps every function symbol to the sum of its argument. Then, we can delete all non-usable rules [17] from R.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ AND
          ↳ QDP
          ↳ QDP
            ↳ UsableRulesProof
            ↳ UsableRulesProof
QDP
  ↳ QTRS Reverse

Q DP problem:
The TRS P consists of the following rules:

C(b(x1)) → C(a(x1))

The TRS R consists of the following rules:

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We have reversed the following QTRS:
The set of rules R is

a(x1) → x1
a(a(b(x1))) → b(b(a(a(x1))))
c(b(x1)) → c(a(x1))

The set Q is empty.
We have obtained the following QTRS:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(c(x)) → a(c(x))

The set Q is empty.

↳ QTRS
  ↳ DependencyPairsProof
  ↳ QTRS Reverse
QTRS

Q restricted rewrite system:
The TRS R consists of the following rules:

a(x) → x
b(a(a(x))) → a(a(b(b(x))))
b(c(x)) → a(c(x))

Q is empty.