Termination of the given ITRSProblem could successfully be proven:



ITRS
  ↳ ITRStoIDPProof

ITRS problem:
The following domains are used:

z

The TRS R consists of the following rules:

divNat(TRUE, x, y) → d(x, y, 0@z)
cond(FALSE, x, y, z) → 0@z
dNat(TRUE, x, y, z) → cond(>=@z(x, z), x, -@z(y, 1@z), z)
cond(TRUE, x, y, z) → +@z(1@z, d(x, +@z(y, 1@z), +@z(+@z(y, 1@z), z)))
d(x, y, z) → dNat(&&(&&(>=@z(x, 0@z), >=@z(y, 1@z)), >=@z(z, 0@z)), x, y, z)
div(x, y) → divNat(&&(>=@z(x, 0@z), >=@z(y, 1@z)), x, y)

The set Q consists of the following terms:

divNat(TRUE, x0, x1)
cond(FALSE, x0, x1, x2)
dNat(TRUE, x0, x1, x2)
cond(TRUE, x0, x1, x2)
d(x0, x1, x2)
div(x0, x1)


Added dependency pairs

↳ ITRS
  ↳ ITRStoIDPProof
IDP
      ↳ UsableRulesProof

I DP problem:
The following domains are used:

z

The ITRS R consists of the following rules:

divNat(TRUE, x, y) → d(x, y, 0@z)
cond(FALSE, x, y, z) → 0@z
dNat(TRUE, x, y, z) → cond(>=@z(x, z), x, -@z(y, 1@z), z)
cond(TRUE, x, y, z) → +@z(1@z, d(x, +@z(y, 1@z), +@z(+@z(y, 1@z), z)))
d(x, y, z) → dNat(&&(&&(>=@z(x, 0@z), >=@z(y, 1@z)), >=@z(z, 0@z)), x, y, z)
div(x, y) → divNat(&&(>=@z(x, 0@z), >=@z(y, 1@z)), x, y)

The integer pair graph contains the following rules and edges:

(0): DIV(x[0], y[0]) → DIVNAT(&&(>=@z(x[0], 0@z), >=@z(y[0], 1@z)), x[0], y[0])
(1): DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1])
(2): DIVNAT(TRUE, x[2], y[2]) → D(x[2], y[2], 0@z)
(3): D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3])
(4): COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4]))

(0) -> (2), if ((x[0]* x[2])∧(y[0]* y[2])∧(&&(>=@z(x[0], 0@z), >=@z(y[0], 1@z)) →* TRUE))


(1) -> (4), if ((z[1]* z[4])∧(x[1]* x[4])∧(-@z(y[1], 1@z) →* y[4])∧(>=@z(x[1], z[1]) →* TRUE))


(2) -> (3), if ((y[2]* y[3])∧(x[2]* x[3]))


(3) -> (1), if ((z[3]* z[1])∧(x[3]* x[1])∧(y[3]* y[1])∧(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)) →* TRUE))


(4) -> (3), if ((+@z(y[4], 1@z) →* y[3])∧(+@z(+@z(y[4], 1@z), z[4]) →* z[3])∧(x[4]* x[3]))



The set Q consists of the following terms:

divNat(TRUE, x0, x1)
cond(FALSE, x0, x1, x2)
dNat(TRUE, x0, x1, x2)
cond(TRUE, x0, x1, x2)
d(x0, x1, x2)
div(x0, x1)


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.

↳ ITRS
  ↳ ITRStoIDPProof
    ↳ IDP
      ↳ UsableRulesProof
IDP
          ↳ IDependencyGraphProof

I DP problem:
The following domains are used:

z

R is empty.
The integer pair graph contains the following rules and edges:

(0): DIV(x[0], y[0]) → DIVNAT(&&(>=@z(x[0], 0@z), >=@z(y[0], 1@z)), x[0], y[0])
(1): DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1])
(2): DIVNAT(TRUE, x[2], y[2]) → D(x[2], y[2], 0@z)
(3): D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3])
(4): COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4]))

(0) -> (2), if ((x[0]* x[2])∧(y[0]* y[2])∧(&&(>=@z(x[0], 0@z), >=@z(y[0], 1@z)) →* TRUE))


(1) -> (4), if ((z[1]* z[4])∧(x[1]* x[4])∧(-@z(y[1], 1@z) →* y[4])∧(>=@z(x[1], z[1]) →* TRUE))


(2) -> (3), if ((y[2]* y[3])∧(x[2]* x[3]))


(3) -> (1), if ((z[3]* z[1])∧(x[3]* x[1])∧(y[3]* y[1])∧(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)) →* TRUE))


(4) -> (3), if ((+@z(y[4], 1@z) →* y[3])∧(+@z(+@z(y[4], 1@z), z[4]) →* z[3])∧(x[4]* x[3]))



The set Q consists of the following terms:

divNat(TRUE, x0, x1)
cond(FALSE, x0, x1, x2)
dNat(TRUE, x0, x1, x2)
cond(TRUE, x0, x1, x2)
d(x0, x1, x2)
div(x0, x1)


The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 1 SCC with 2 less nodes.

↳ ITRS
  ↳ ITRStoIDPProof
    ↳ IDP
      ↳ UsableRulesProof
        ↳ IDP
          ↳ IDependencyGraphProof
IDP
              ↳ IDPNonInfProof

I DP problem:
The following domains are used:

z

R is empty.
The integer pair graph contains the following rules and edges:

(4): COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4]))
(1): DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1])
(3): D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3])

(1) -> (4), if ((z[1]* z[4])∧(x[1]* x[4])∧(-@z(y[1], 1@z) →* y[4])∧(>=@z(x[1], z[1]) →* TRUE))


(3) -> (1), if ((z[3]* z[1])∧(x[3]* x[1])∧(y[3]* y[1])∧(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)) →* TRUE))


(4) -> (3), if ((+@z(y[4], 1@z) →* y[3])∧(+@z(+@z(y[4], 1@z), z[4]) →* z[3])∧(x[4]* x[3]))



The set Q consists of the following terms:

divNat(TRUE, x0, x1)
cond(FALSE, x0, x1, x2)
dNat(TRUE, x0, x1, x2)
cond(TRUE, x0, x1, x2)
d(x0, x1, x2)
div(x0, x1)


The constraints were generated the following way:
The DP Problem is simplified using the Induction Calculus [NONINF] with the following steps:
Note that final constraints are written in bold face.


For Pair COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4])) the following chains were created:




For Pair DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1]) the following chains were created:




For Pair D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3]) the following chains were created:




To summarize, we get the following constraints P for the following pairs.



The constraints for P> respective Pbound are constructed from P where we just replace every occurence of "t ≥ s" in P by "t > s" respective "t ≥ c". Here c stands for the fresh constant used for Pbound.
Using the following integer polynomial ordering the resulting constraints can be solved
Polynomial interpretation over integers[POLO]:

POL(-@z(x1, x2)) = x1 + (-1)x2   
POL(DNAT(x1, x2, x3, x4)) = -1 + (-1)x4 + x3 + x2 + (-1)x1   
POL(COND(x1, x2, x3, x4)) = 1 + (-1)x4 + x2   
POL(>=@z(x1, x2)) = 0   
POL(0@z) = 0   
POL(TRUE) = -1   
POL(&&(x1, x2)) = -1   
POL(+@z(x1, x2)) = x1 + x2   
POL(D(x1, x2, x3)) = (-1)x3 + x2 + x1   
POL(FALSE) = 1   
POL(1@z) = 1   
POL(undefined) = -1   

The following pairs are in P>:

COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4]))

The following pairs are in Pbound:

COND(TRUE, x[4], y[4], z[4]) → D(x[4], +@z(y[4], 1@z), +@z(+@z(y[4], 1@z), z[4]))

The following pairs are in P:

DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1])
D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3])

At least the following rules have been oriented under context sensitive arithmetic replacement:

FALSE1&&(FALSE, FALSE)1
-@z1
&&(TRUE, TRUE)1TRUE1
+@z1
FALSE1&&(FALSE, TRUE)1
FALSE1&&(TRUE, FALSE)1


↳ ITRS
  ↳ ITRStoIDPProof
    ↳ IDP
      ↳ UsableRulesProof
        ↳ IDP
          ↳ IDependencyGraphProof
            ↳ IDP
              ↳ IDPNonInfProof
IDP
                  ↳ IDependencyGraphProof

I DP problem:
The following domains are used:

z

R is empty.
The integer pair graph contains the following rules and edges:

(1): DNAT(TRUE, x[1], y[1], z[1]) → COND(>=@z(x[1], z[1]), x[1], -@z(y[1], 1@z), z[1])
(3): D(x[3], y[3], z[3]) → DNAT(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)), x[3], y[3], z[3])

(3) -> (1), if ((z[3]* z[1])∧(x[3]* x[1])∧(y[3]* y[1])∧(&&(&&(>=@z(x[3], 0@z), >=@z(y[3], 1@z)), >=@z(z[3], 0@z)) →* TRUE))



The set Q consists of the following terms:

divNat(TRUE, x0, x1)
cond(FALSE, x0, x1, x2)
dNat(TRUE, x0, x1, x2)
cond(TRUE, x0, x1, x2)
d(x0, x1, x2)
div(x0, x1)


The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 2 less nodes.