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:

if(FALSE, u, v) → v
fNat(TRUE, x, y) → f(>@z(x, y), trunc(x), +@z(y, 1@z))
trunc(x) → if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))
if(TRUE, u, v) → u
f(TRUE, x, y) → fNat(&&(>=@z(x, 0@z), >=@z(y, 0@z)), x, y)

The set Q consists of the following terms:

if(FALSE, x0, x1)
fNat(TRUE, x0, x1)
trunc(x0)
if(TRUE, x0, x1)
f(TRUE, 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:

if(FALSE, u, v) → v
fNat(TRUE, x, y) → f(>@z(x, y), trunc(x), +@z(y, 1@z))
trunc(x) → if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))
if(TRUE, u, v) → u
f(TRUE, x, y) → fNat(&&(>=@z(x, 0@z), >=@z(y, 0@z)), x, y)

The integer pair graph contains the following rules and edges:

(0): FNAT(TRUE, x[0], y[0]) → TRUNC(x[0])
(1): FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z))
(2): F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2])
(3): TRUNC(x[3]) → IF(=@z(%@z(x[3], 2@z), 0@z), x[3], -@z(x[3], 1@z))

(0) -> (3), if ((x[0]* x[3]))


(1) -> (2), if ((trunc(x[1]) →* x[2])∧(+@z(y[1], 1@z) →* y[2])∧(>@z(x[1], y[1]) →* TRUE))


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


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



The set Q consists of the following terms:

if(FALSE, x0, x1)
fNat(TRUE, x0, x1)
trunc(x0)
if(TRUE, x0, x1)
f(TRUE, 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

The ITRS R consists of the following rules:

if(FALSE, u, v) → v
trunc(x) → if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))
if(TRUE, u, v) → u

The integer pair graph contains the following rules and edges:

(0): FNAT(TRUE, x[0], y[0]) → TRUNC(x[0])
(1): FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z))
(2): F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2])
(3): TRUNC(x[3]) → IF(=@z(%@z(x[3], 2@z), 0@z), x[3], -@z(x[3], 1@z))

(0) -> (3), if ((x[0]* x[3]))


(1) -> (2), if ((trunc(x[1]) →* x[2])∧(+@z(y[1], 1@z) →* y[2])∧(>@z(x[1], y[1]) →* TRUE))


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


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



The set Q consists of the following terms:

if(FALSE, x0, x1)
fNat(TRUE, x0, x1)
trunc(x0)
if(TRUE, x0, x1)
f(TRUE, 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

The ITRS R consists of the following rules:

if(FALSE, u, v) → v
trunc(x) → if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))
if(TRUE, u, v) → u

The integer pair graph contains the following rules and edges:

(1): FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z))
(2): F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2])

(1) -> (2), if ((trunc(x[1]) →* x[2])∧(+@z(y[1], 1@z) →* y[2])∧(>@z(x[1], y[1]) →* TRUE))


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



The set Q consists of the following terms:

if(FALSE, x0, x1)
fNat(TRUE, x0, x1)
trunc(x0)
if(TRUE, x0, x1)
f(TRUE, 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 FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z)) the following chains were created:




For Pair F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2]) 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(0@z) = 0   
POL(TRUE) = -1   
POL(&&(x1, x2)) = -1   
POL(2@z) = 2   
POL(FALSE) = 1   
POL(F(x1, x2, x3)) = x2 + (-1)x3   
POL(>@z(x1, x2)) = -1   
POL(=@z(x1, x2)) = -1   
POL(if(x1, x2, x3)) = max{x2, x3}   
POL(>=@z(x1, x2)) = -1   
POL(+@z(x1, x2)) = x1 + x2   
POL(trunc(x1)) = x1   
POL(1@z) = 1   
POL(undefined) = -1   
POL(FNAT(x1, x2, x3)) = -1 + (-1)x1 + x2 + (-1)x3   

The following pairs are in P>:

FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z))

The following pairs are in Pbound:

FNAT(TRUE, x[1], y[1]) → F(>@z(x[1], y[1]), trunc(x[1]), +@z(y[1], 1@z))

The following pairs are in P:

F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2])

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

FALSE1&&(FALSE, FALSE)1
-@z1
if(FALSE, u, v)1v1
if(TRUE, u, v)1u1
trunc(x)1if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))1
TRUE1&&(TRUE, TRUE)1
+@z1
FALSE1&&(FALSE, TRUE)1
FALSE1&&(TRUE, FALSE)1
%@z1


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

I DP problem:
The following domains are used:

z

The ITRS R consists of the following rules:

if(FALSE, u, v) → v
trunc(x) → if(=@z(%@z(x, 2@z), 0@z), x, -@z(x, 1@z))
if(TRUE, u, v) → u

The integer pair graph contains the following rules and edges:

(2): F(TRUE, x[2], y[2]) → FNAT(&&(>=@z(x[2], 0@z), >=@z(y[2], 0@z)), x[2], y[2])


The set Q consists of the following terms:

if(FALSE, x0, x1)
fNat(TRUE, x0, x1)
trunc(x0)
if(TRUE, x0, x1)
f(TRUE, x0, x1)


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