NO Termination w.r.t. Q proof of EEG_IJCAR_12_emmes-nonloop-ex2_4.ari

(0) Obligation:

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

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

Q is empty.

(1) AAECC Innermost (EQUIVALENT transformation)

We have applied [NOC,AAECCNOC] to switch to innermost. The TRS R 1 is

gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The TRS R 2 is

f(true, x, y) → f(gt(x, y), double(x), s(y))

The signature Sigma is {f}

(2) Obligation:

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

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

(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:

F(true, x, y) → F(gt(x, y), double(x), s(y))
F(true, x, y) → GT(x, y)
F(true, x, y) → DOUBLE(x)
GT(s(x), s(y)) → GT(x, y)
DOUBLE(x) → TIMES(x, s(s(0)))
TIMES(s(x), y) → PLUS(y, times(x, y))
TIMES(s(x), y) → TIMES(x, y)
PLUS(s(x), y) → PLUS(x, s(y))

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(5) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 4 SCCs with 4 less nodes.

(6) Complex Obligation (AND)

(7) Obligation:

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

PLUS(s(x), y) → PLUS(x, s(y))

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(8) UsableRulesProof (EQUIVALENT transformation)

As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R.

(9) Obligation:

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

PLUS(s(x), y) → PLUS(x, s(y))

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

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(10) QReductionProof (EQUIVALENT transformation)

We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN].

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

(11) Obligation:

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

PLUS(s(x), y) → PLUS(x, s(y))

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

(12) 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:

  • PLUS(s(x), y) → PLUS(x, s(y))
    The graph contains the following edges 1 > 1

(13) YES

(14) Obligation:

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

TIMES(s(x), y) → TIMES(x, y)

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(15) UsableRulesProof (EQUIVALENT transformation)

As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R.

(16) Obligation:

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

TIMES(s(x), y) → TIMES(x, y)

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

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(17) QReductionProof (EQUIVALENT transformation)

We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN].

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

(18) Obligation:

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

TIMES(s(x), y) → TIMES(x, y)

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

(19) 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:

  • TIMES(s(x), y) → TIMES(x, y)
    The graph contains the following edges 1 > 1, 2 >= 2

(20) YES

(21) Obligation:

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

GT(s(x), s(y)) → GT(x, y)

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(22) UsableRulesProof (EQUIVALENT transformation)

As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R.

(23) Obligation:

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

GT(s(x), s(y)) → GT(x, y)

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

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(24) QReductionProof (EQUIVALENT transformation)

We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN].

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

(25) Obligation:

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

GT(s(x), s(y)) → GT(x, y)

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

(26) 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:

  • GT(s(x), s(y)) → GT(x, y)
    The graph contains the following edges 1 > 1, 2 > 2

(27) YES

(28) Obligation:

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

F(true, x, y) → F(gt(x, y), double(x), s(y))

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

The set Q consists of the following terms:

f(true, x0, x1)
gt(s(x0), 0)
gt(0, x0)
gt(s(x0), s(x1))
double(x0)
times(0, x0)
times(s(x0), x1)
plus(0, x0)
plus(s(x0), x1)

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

(29) MNOCProof (EQUIVALENT transformation)

We use the modular non-overlap check [FROCOS05] to decrease Q to the empty set.

(30) Obligation:

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

F(true, x, y) → F(gt(x, y), double(x), s(y))

The TRS R consists of the following rules:

f(true, x, y) → f(gt(x, y), double(x), s(y))
gt(s(x), 0) → true
gt(0, y) → false
gt(s(x), s(y)) → gt(x, y)
double(x) → times(x, s(s(0)))
times(0, y) → 0
times(s(x), y) → plus(y, times(x, y))
plus(0, y) → y
plus(s(x), y) → plus(x, s(y))

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

(31) NonLoopProof (COMPLETE transformation)

By Theorem 8 [NONLOOP] we deduce infiniteness of the QDP.
We apply the theorem with m = 1, b = 1,
σ' = [zr3 / s(zr3)], and μ' = [zr3 / times(s(zr3), s(s(0)))] on the rule
F(true, s(s(s(zr3))), s(zr2))[zr3 / s(zr3), zr2 / s(zr2)]n[zr2 / 0] → F(true, s(s(s(s(zr3)))), s(s(zr2)))[zr2 / s(zr2), zr3 / s(s(zr3))]n[zr2 / 0, zr3 / times(s(zr3), s(s(0)))]
This rule is correct for the QDP as the following derivation shows:

F(true, s(s(s(zr3))), s(zr2))[zr3 / s(zr3), zr2 / s(zr2)]n[zr2 / 0] → F(true, s(s(s(s(zr3)))), s(s(zr2)))[zr2 / s(zr2), zr3 / s(s(zr3))]n[zr2 / 0, zr3 / times(s(zr3), s(s(0)))]
    by Equivalence by Irrelevant Pattern Substitutions σ: [zr2 / s(zr2), zr3 / s(s(zr3))] µ: [zr2 / 0, zr3 / times(s(zr3), s(s(0)))]
    intermediate steps: Equiv IPS (lhs) - Instantiate mu - Equiv DR (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs) - Equiv Sµ (lhs) - Instantiate mu - Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiate mu - Equiv DR (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs)
    F(true, s(s(zl2)), s(zl3))[zl2 / s(zl2), zl3 / s(zl3)]n[zl2 / y1, zl3 / 0] → F(true, s(s(s(s(zt1)))), s(s(zr3)))[zr3 / s(zr3), zt1 / s(s(zt1))]n[zr3 / 0, zt1 / times(y1, s(s(0)))]
        by Rewrite sigma at the term of variable: zt1 with the rewrite sequence : [([],plus(s(x), y) -> plus(x, s(y))), ([],plus(s(x), y) -> plus(x, s(y))), ([],plus(0, y) -> y)]
        F(true, s(s(zl2)), s(zl3))[zl2 / s(zl2), zl3 / s(zl3)]n[zl2 / y1, zl3 / 0] → F(true, s(s(s(s(zt1)))), s(s(zr3)))[zr3 / s(zr3), zt1 / plus(s(s(0)), zt1)]n[zr3 / 0, zt1 / times(y1, s(s(0)))]
            by Rewrite t with the rewrite sequence : [([1],plus(s(x), y) -> plus(x, s(y))), ([1],plus(s(x), y) -> plus(x, s(y))), ([1],plus(0, y) -> y), ([1,0,0],plus(s(x), y) -> plus(x, s(y))), ([1,0,0],plus(s(x), y) -> plus(x, s(y))), ([1,0,0],plus(0, y) -> y)]
            intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs)
            F(true, s(s(zl2)), s(zl3))[zr2 / s(zr2), zr3 / s(zr3), zt1 / plus(s(s(0)), zt1), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / y1, zr3 / 0, zt1 / times(y1, s(s(0))), zl2 / y1, zl3 / 0, x0 / y1] → F(true, plus(s(s(0)), plus(s(s(0)), zt1)), s(s(zr3)))[zr2 / s(zr2), zr3 / s(zr3), zt1 / plus(s(s(0)), zt1), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / y1, zr3 / 0, zt1 / times(y1, s(s(0))), zl2 / y1, zl3 / 0, x0 / y1]
                by Narrowing at position: [1]
                intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiate mu - Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv DR (rhs) - Equiv DR (lhs) - Equiv DR (rhs) - Equiv DR (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs)
                F(true, s(s(zl2)), s(zl3))[zr2 / s(zr2), zr3 / s(zr3), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / x0, zr3 / 0, zl2 / x0, zl3 / 0] → F(true, times(s(s(zr2)), s(s(0))), s(s(zr3)))[zr2 / s(zr2), zr3 / s(zr3), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / x0, zr3 / 0, zl2 / x0, zl3 / 0]
                    by Narrowing at position: [1]
                    intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv DR (rhs) - Equiv DR (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs)
                    F(true, s(s(zl2)), s(zl3))[zr2 / s(zr2), zr3 / s(zr3), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / y0, zr3 / 0, zl2 / y0, zl3 / 0] → F(true, double(s(s(zr2))), s(s(zr3)))[zr2 / s(zr2), zr3 / s(zr3), zl2 / s(zl2), zl3 / s(zl3)]n[zr2 / y0, zr3 / 0, zl2 / y0, zl3 / 0]
                        by Narrowing at position: [0]
                        intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiation - Equiv Sµ (rhs) - Equiv Sµ (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs)
                        F(true, s(zs2), s(zs3))[zs2 / s(zs2), zs3 / s(zs3)]n[zs2 / y1, zs3 / y0] → F(gt(y1, y0), double(s(zs2)), s(s(zs3)))[zs2 / s(zs2), zs3 / s(zs3)]n[zs2 / y1, zs3 / y0]
                            by Narrowing at position: [0]
                            intermediate steps: Instantiate mu - Instantiate Sigma - Instantiation - Instantiation - Instantiation
                            F(true, x, y)[ ]n[ ] → F(gt(x, y), double(x), s(y))[ ]n[ ]
                                by Rule from TRS P

                            intermediate steps: Equiv IPS (rhs) - Equiv IPS (rhs) - Instantiation - Equiv DR (lhs) - Instantiation - Equiv DR (lhs)
                            gt(s(x), s(y))[x / s(x), y / s(y)]n[ ] → gt(x, y)[ ]n[ ]
                                by PatternCreation I with delta: [ ], theta: [ ], sigma: [x / s(x), y / s(y)]
                                gt(s(x), s(y))[ ]n[ ] → gt(x, y)[ ]n[ ]
                                    by Rule from TRS R

                        intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiation
                        gt(s(x), 0)[ ]n[ ] → true[ ]n[ ]
                            by Rule from TRS R

                    intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiate mu - Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiate Sigma - Instantiation - Instantiation
                    double(x)[ ]n[ ] → times(x, s(s(0)))[ ]n[ ]
                        by Rule from TRS R

                intermediate steps: Equiv IPS (rhs) - Equiv IPS (lhs) - Equiv IPS (rhs) - Equiv IPS (lhs) - Instantiation - Equiv DR (lhs) - Expand Sigma - Instantiation - Equiv DR (rhs) - Equiv DR (lhs) - Instantiation - Equiv DR (rhs) - Equiv DR (lhs) - Equiv IPS (rhs)
                times(s(x), y)[x / s(x)]n[ ] → plus(y, z)[x / s(x), z / plus(y, z)]n[z / times(x, y)]
                    by PatternCreation II with pi: [1], sigma: [x / s(x)]
                    times(s(x), y)[ ]n[ ] → plus(y, times(x, y))[ ]n[ ]
                        by Rule from TRS R

(32) NO