YES Termination w.r.t. Q proof of AProVE_08_id_inc.ari

Termination w.r.t. Q of the given QTRS could be proven:

0 QTRS
↳1 DependencyPairsProof (⇔, 0 ms)
↳2 QDP
↳3 DependencyGraphProof (⇔, 0 ms)
↳4 AND
    ↳5 QDP
        ↳6 UsableRulesProof (⇔, 0 ms)
        ↳7 QDP
        ↳8 QDPSizeChangeProof (⇔, 0 ms)
        ↳9 YES
    ↳10 QDP
        ↳11 UsableRulesReductionPairsProof (⇔, 0 ms)
        ↳12 QDP
        ↳13 QDPOrderProof (⇔, 16 ms)
        ↳14 QDP
        ↳15 QDPOrderProof (⇔, 0 ms)
        ↳16 QDP
        ↳17 PisEmptyProof (⇔, 0 ms)
        ↳18 YES

(0) Obligation:

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

f(s(x)) → f(id_inc(c(x, x)))
f(c(s(x), y)) → g(c(x, y))
g(c(s(x), y)) → g(c(y, x))
g(c(x, s(y))) → g(c(y, x))
g(c(x, x)) → f(x)
id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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:

F(s(x)) → F(id_inc(c(x, x)))
F(s(x)) → ID_INC(c(x, x))
F(c(s(x), y)) → G(c(x, y))
G(c(s(x), y)) → G(c(y, x))
G(c(x, s(y))) → G(c(y, x))
G(c(x, x)) → F(x)
ID_INC(c(x, y)) → ID_INC(x)
ID_INC(c(x, y)) → ID_INC(y)
ID_INC(s(x)) → ID_INC(x)

The TRS R consists of the following rules:

f(s(x)) → f(id_inc(c(x, x)))
f(c(s(x), y)) → g(c(x, y))
g(c(s(x), y)) → g(c(y, x))
g(c(x, s(y))) → g(c(y, x))
g(c(x, x)) → f(x)
id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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 2 SCCs with 1 less node.

(4) Complex Obligation (AND)

(5) Obligation:

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

ID_INC(c(x, y)) → ID_INC(y)
ID_INC(c(x, y)) → ID_INC(x)
ID_INC(s(x)) → ID_INC(x)

The TRS R consists of the following rules:

f(s(x)) → f(id_inc(c(x, x)))
f(c(s(x), y)) → g(c(x, y))
g(c(s(x), y)) → g(c(y, x))
g(c(x, s(y))) → g(c(y, x))
g(c(x, x)) → f(x)
id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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

(6) 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.

(7) Obligation:

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

ID_INC(c(x, y)) → ID_INC(y)
ID_INC(c(x, y)) → ID_INC(x)
ID_INC(s(x)) → ID_INC(x)

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

(8) QDPSizeChangeProof (EQUIVALENT transformation)

By using the subterm criterion [SUBTERM_CRITERION] together with the size-change analysis [AAECC05] 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:

  • ID_INC(c(x, y)) → ID_INC(y)
    The graph contains the following edges 1 > 1

  • ID_INC(c(x, y)) → ID_INC(x)
    The graph contains the following edges 1 > 1

  • ID_INC(s(x)) → ID_INC(x)
    The graph contains the following edges 1 > 1

(9) YES

(10) Obligation:

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

F(c(s(x), y)) → G(c(x, y))
G(c(s(x), y)) → G(c(y, x))
G(c(x, s(y))) → G(c(y, x))
G(c(x, x)) → F(x)
F(s(x)) → F(id_inc(c(x, x)))

The TRS R consists of the following rules:

f(s(x)) → f(id_inc(c(x, x)))
f(c(s(x), y)) → g(c(x, y))
g(c(s(x), y)) → g(c(y, x))
g(c(x, s(y))) → g(c(y, x))
g(c(x, x)) → f(x)
id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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

(11) UsableRulesReductionPairsProof (EQUIVALENT transformation)

By using the usable rules with reduction pair processor [LPAR04] with a polynomial ordering [POLO], all dependency pairs and the corresponding usable rules [FROCOS05] can be oriented non-strictly. All non-usable rules are removed, and those dependency pairs and usable rules that have been oriented strictly or contain non-usable symbols in their left-hand side are removed as well.

No dependency pairs are removed.

The following rules are removed from R:

f(s(x)) → f(id_inc(c(x, x)))
f(c(s(x), y)) → g(c(x, y))
g(c(s(x), y)) → g(c(y, x))
g(c(x, s(y))) → g(c(y, x))
g(c(x, x)) → f(x)
Used ordering: POLO with Polynomial interpretation [POLO]:

POL(0) = 0   
POL(F(x1)) = 2 + x1   
POL(G(x1)) = 2 + x1   
POL(c(x1, x2)) = x1 + x2   
POL(id_inc(x1)) = x1   
POL(s(x1)) = 2·x1   

(12) Obligation:

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

F(c(s(x), y)) → G(c(x, y))
G(c(s(x), y)) → G(c(y, x))
G(c(x, s(y))) → G(c(y, x))
G(c(x, x)) → F(x)
F(s(x)) → F(id_inc(c(x, x)))

The TRS R consists of the following rules:

id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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

(13) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04,JAR06].


The following pairs can be oriented strictly and are deleted.


F(c(s(x), y)) → G(c(x, y))
G(c(s(x), y)) → G(c(y, x))
G(c(x, s(y))) → G(c(y, x))
G(c(x, x)) → F(x)
The remaining pairs can at least be oriented weakly.
Used ordering: Polynomial interpretation [POLO,RATPOLO]:

POL(0) = [4]   
POL(F(x1)) = [4]x1   
POL(G(x1)) = [4] + [4]x1   
POL(c(x1, x2)) = [1/2]x1 + [1/2]x2   
POL(id_inc(x1)) = [4] + [4]x1   
POL(s(x1)) = [4] + [4]x1   
The value of delta used in the strict ordering is 4.
The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:

id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

(14) Obligation:

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

F(s(x)) → F(id_inc(c(x, x)))

The TRS R consists of the following rules:

id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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

(15) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04,JAR06].


The following pairs can be oriented strictly and are deleted.


F(s(x)) → F(id_inc(c(x, x)))
The remaining pairs can at least be oriented weakly.
Used ordering: Combined order from the following AFS and order.
F(x1)  =  x1
s(x1)  =  s
id_inc(x1)  =  id_inc
c(x1, x2)  =  c

Knuth-Bendix order [KBO] with precedence:
s > idinc > c

and weight map:

s=1
id_inc=1
c=1

The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented:

id_inc(c(x, y)) → c(id_inc(x), id_inc(y))

(16) Obligation:

Q DP problem:
P is empty.
The TRS R consists of the following rules:

id_inc(c(x, y)) → c(id_inc(x), id_inc(y))
id_inc(s(x)) → s(id_inc(x))
id_inc(0) → 0
id_inc(0) → s(0)

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

(17) PisEmptyProof (EQUIVALENT transformation)

The TRS P is empty. Hence, there is no (P,Q,R) chain.

(18) YES