(0) Obligation:

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

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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:

C(c(c(y))) → C(c(a(y, 0)))
C(c(c(y))) → C(a(y, 0))
C(a(a(0, x), y)) → C(c(c(0)))
C(a(a(0, x), y)) → C(c(0))
C(a(a(0, x), y)) → C(0)

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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 1 less node.

(4) Obligation:

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

C(c(c(y))) → C(a(y, 0))
C(a(a(0, x), y)) → C(c(c(0)))
C(c(c(y))) → C(c(a(y, 0)))
C(a(a(0, x), y)) → C(c(0))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(5) Narrowing (EQUIVALENT transformation)

By narrowing [LPAR04] the rule C(a(a(0, x), y)) → C(c(0)) at position [0] we obtained the following new rules [LPAR04]:

C(a(a(0, y0), y1)) → C(0)

(6) Obligation:

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

C(c(c(y))) → C(a(y, 0))
C(a(a(0, x), y)) → C(c(c(0)))
C(c(c(y))) → C(c(a(y, 0)))
C(a(a(0, y0), y1)) → C(0)

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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 1 less node.

(8) Obligation:

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

C(a(a(0, x), y)) → C(c(c(0)))
C(c(c(y))) → C(c(a(y, 0)))
C(c(c(y))) → C(a(y, 0))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(9) Narrowing (EQUIVALENT transformation)

By narrowing [LPAR04] the rule C(c(c(y))) → C(c(a(y, 0))) at position [0] we obtained the following new rules [LPAR04]:

C(c(c(a(0, x0)))) → C(a(c(c(c(0))), 0))
C(c(c(y0))) → C(a(y0, 0))

(10) Obligation:

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

C(a(a(0, x), y)) → C(c(c(0)))
C(c(c(y))) → C(a(y, 0))
C(c(c(a(0, x0)))) → C(a(c(c(c(0))), 0))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(11) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04].


The following pairs can be oriented strictly and are deleted.


C(c(c(a(0, x0)))) → C(a(c(c(c(0))), 0))
The remaining pairs can at least be oriented weakly.
Used ordering: Matrix interpretation [MATRO]:

POL(C(x1)) =
/0\
\0/
+
/01\
\00/
·x1

POL(a(x1, x2)) =
/0\
\1/
+
/00\
\00/
·x1 +
/01\
\01/
·x2

POL(0) =
/0\
\0/

POL(c(x1)) =
/1\
\0/
+
/10\
\11/
·x1

The following usable rules [FROCOS05] were oriented:

c(y) → y
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(c(c(y))) → c(c(a(y, 0)))

(12) Obligation:

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

C(a(a(0, x), y)) → C(c(c(0)))
C(c(c(y))) → C(a(y, 0))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(13) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04].


The following pairs can be oriented strictly and are deleted.


C(c(c(y))) → C(a(y, 0))
The remaining pairs can at least be oriented weakly.
Used ordering: Matrix interpretation [MATRO] with arctic natural numbers [ARCTIC]:

POL(C(x1)) =
/-I\
|-I|
\0A/
+
/0A-I-I\
|-I-I-I|
\3A0A2A/
·x1

POL(a(x1, x2)) =
/-I\
|0A|
\2A/
+
/0A-I0A\
|0A-I-I|
\-I-I-I/
·x1 +
/-I-I0A\
|-I0A-I|
\-I-I-I/
·x2

POL(0) =
/0A\
|0A|
\-I/

POL(c(x1)) =
/0A\
|2A|
\-I/
+
/1A0A-I\
|-I1A1A|
\0A-I0A/
·x1

The following usable rules [FROCOS05] were oriented:

c(y) → y
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(c(c(y))) → c(c(a(y, 0)))

(14) Obligation:

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

C(a(a(0, x), y)) → C(c(c(0)))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(15) Narrowing (EQUIVALENT transformation)

By narrowing [LPAR04] the rule C(a(a(0, x), y)) → C(c(c(0))) at position [0] we obtained the following new rules [LPAR04]:

C(a(a(0, y0), y1)) → C(c(0))

(16) Obligation:

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

C(a(a(0, y0), y1)) → C(c(0))

The TRS R consists of the following rules:

c(c(c(y))) → c(c(a(y, 0)))
c(a(a(0, x), y)) → a(c(c(c(0))), y)
c(y) → y

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

(17) UsableRulesProof (EQUIVALENT transformation)

We can use the usable rules and reduction pair processor [LPAR04] with the Ce-compatible extension of the polynomial order that maps every function symbol to the sum of its arguments. Then, we can delete all non-usable rules [FROCOS05] from R.

(18) Obligation:

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

C(a(a(0, y0), y1)) → C(c(0))

The TRS R consists of the following rules:

c(y) → y

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

(19) MNOCProof (EQUIVALENT transformation)

We use the modular non-overlap check [LPAR04] to enlarge Q to all left-hand sides of R.

(20) Obligation:

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

C(a(a(0, y0), y1)) → C(c(0))

The TRS R consists of the following rules:

c(y) → y

The set Q consists of the following terms:

c(x0)

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

(21) Rewriting (EQUIVALENT transformation)

By rewriting [LPAR04] the rule C(a(a(0, y0), y1)) → C(c(0)) at position [0] we obtained the following new rules [LPAR04]:

C(a(a(0, y0), y1)) → C(0)

(22) Obligation:

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

C(a(a(0, y0), y1)) → C(0)

The TRS R consists of the following rules:

c(y) → y

The set Q consists of the following terms:

c(x0)

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

(23) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 1 less node.

(24) TRUE