Term Rewriting System R:
[x, y, u, z]
perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))

Innermost Termination of R to be shown.



   R
Dependency Pair Analysis



R contains the following Dependency Pairs:

PERFECTP(s(x)) -> F(x, s(0), s(x), s(x))
F(s(x), 0, z, u) -> F(x, u, minus(z, s(x)), u)
F(s(x), s(y), z, u) -> F(s(x), minus(y, x), z, u)
F(s(x), s(y), z, u) -> F(x, u, z, u)

Furthermore, R contains one SCC.


   R
DPs
       →DP Problem 1
Instantiation Transformation


Dependency Pairs:

F(s(x), 0, z, u) -> F(x, u, minus(z, s(x)), u)
F(s(x), s(y), z, u) -> F(x, u, z, u)


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




On this DP problem, an Instantiation SCC transformation can be performed.
As a result of transforming the rule

F(s(x), 0, z, u) -> F(x, u, minus(z, s(x)), u)
two new Dependency Pairs are created:

F(s(x''), 0, minus(z'', s(s(x''))), 0) -> F(x'', 0, minus(minus(z'', s(s(x''))), s(x'')), 0)
F(s(x''), 0, z'', 0) -> F(x'', 0, minus(z'', s(x'')), 0)

The transformation is resulting in two new DP problems:



   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Instantiation Transformation
           →DP Problem 3
Inst


Dependency Pairs:

F(s(x''), 0, z'', 0) -> F(x'', 0, minus(z'', s(x'')), 0)
F(s(x''), 0, minus(z'', s(s(x''))), 0) -> F(x'', 0, minus(minus(z'', s(s(x''))), s(x'')), 0)


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




On this DP problem, an Instantiation SCC transformation can be performed.
As a result of transforming the rule

F(s(x''), 0, z'', 0) -> F(x'', 0, minus(z'', s(x'')), 0)
two new Dependency Pairs are created:

F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x''''), 0, minus(z'''', s(s(x''''))), 0) -> F(x'''', 0, minus(minus(z'''', s(s(x''''))), s(x'''')), 0)

The transformation is resulting in one new DP problem:



   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
             ...
               →DP Problem 4
Instantiation Transformation
           →DP Problem 3
Inst


Dependency Pairs:

F(s(x''''), 0, minus(z'''', s(s(x''''))), 0) -> F(x'''', 0, minus(minus(z'''', s(s(x''''))), s(x'''')), 0)
F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x''), 0, minus(z'', s(s(x''))), 0) -> F(x'', 0, minus(minus(z'', s(s(x''))), s(x'')), 0)


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




On this DP problem, an Instantiation SCC transformation can be performed.
As a result of transforming the rule

F(s(x''), 0, minus(z'', s(s(x''))), 0) -> F(x'', 0, minus(minus(z'', s(s(x''))), s(x'')), 0)
three new Dependency Pairs are created:

F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x'''), 0, minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), s(x''')), 0)
F(s(x'''), 0, minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), s(x''')), 0)

The transformation is resulting in one new DP problem:



   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
             ...
               →DP Problem 6
Argument Filtering and Ordering
           →DP Problem 3
Inst


Dependency Pairs:

F(s(x'''), 0, minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), s(x''')), 0)
F(s(x'''), 0, minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), s(x''')), 0)
F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x''''), 0, minus(z'''', s(s(x''''))), 0) -> F(x'''', 0, minus(minus(z'''', s(s(x''''))), s(x'''')), 0)


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




The following dependency pairs can be strictly oriented:

F(s(x'''), 0, minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(z'''''', s(s(s(x''')))), s(s(x'''))), s(x''')), 0)
F(s(x'''), 0, minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), 0) -> F(x''', 0, minus(minus(minus(minus(z'''''', s(s(s(s(x'''))))), s(s(s(x''')))), s(s(x'''))), s(x''')), 0)
F(s(x''''), 0, minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), 0) -> F(x'''', 0, minus(minus(minus(z'''', s(s(s(x'''')))), s(s(x''''))), s(x'''')), 0)
F(s(x''''), 0, minus(z'''', s(s(x''''))), 0) -> F(x'''', 0, minus(minus(z'''', s(s(x''''))), s(x'''')), 0)


There are no usable rules for innermost w.r.t. to the AFS that need to be oriented.
Used ordering: Homeomorphic Embedding Order with EMB
resulting in one new DP problem.
Used Argument Filtering System:
F(x1, x2, x3, x4) -> F(x1, x2, x3, x4)
s(x1) -> s(x1)
minus(x1, x2) -> x1


   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
             ...
               →DP Problem 8
Dependency Graph
           →DP Problem 3
Inst


Dependency Pair:


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




Using the Dependency Graph resulted in no new DP problems.


   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
           →DP Problem 3
Instantiation Transformation


Dependency Pair:

F(s(x), s(y), z, u) -> F(x, u, z, u)


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




On this DP problem, an Instantiation SCC transformation can be performed.
As a result of transforming the rule

F(s(x), s(y), z, u) -> F(x, u, z, u)
one new Dependency Pair is created:

F(s(x''), s(y'), z'', s(y')) -> F(x'', s(y'), z'', s(y'))

The transformation is resulting in one new DP problem:



   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
           →DP Problem 3
Inst
             ...
               →DP Problem 5
Forward Instantiation Transformation


Dependency Pair:

F(s(x''), s(y'), z'', s(y')) -> F(x'', s(y'), z'', s(y'))


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




On this DP problem, a Forward Instantiation SCC transformation can be performed.
As a result of transforming the rule

F(s(x''), s(y'), z'', s(y')) -> F(x'', s(y'), z'', s(y'))
one new Dependency Pair is created:

F(s(s(x'''')), s(y'0), z'''', s(y'0)) -> F(s(x''''), s(y'0), z'''', s(y'0))

The transformation is resulting in one new DP problem:



   R
DPs
       →DP Problem 1
Inst
           →DP Problem 2
Inst
           →DP Problem 3
Inst
             ...
               →DP Problem 7
Argument Filtering and Ordering


Dependency Pair:

F(s(s(x'''')), s(y'0), z'''', s(y'0)) -> F(s(x''''), s(y'0), z'''', s(y'0))


Rules:


perfectp(0) -> false
perfectp(s(x)) -> f(x, s(0), s(x), s(x))
f(0, y, 0, u) -> true
f(0, y, s(z), u) -> false
f(s(x), 0, z, u) -> f(x, u, minus(z, s(x)), u)
f(s(x), s(y), z, u) -> if(le(x, y), f(s(x), minus(y, x), z, u), f(x, u, z, u))


Strategy:

innermost




The following dependency pair can be strictly oriented:

F(s(s(x'''')), s(y'0), z'''', s(y'0)) -> F(s(x''''), s(y'0), z'''', s(y'0))


There are no usable rules for innermost w.r.t. to the AFS that need to be oriented.
Used ordering: Homeomorphic Embedding Order with EMB
resulting in one new DP problem.
Used Argument Filtering System:
F(x1, x2, x3, x4) -> F(x1, x2, x3, x4)
s(x1) -> s(x1)

Innermost Termination of R successfully shown.
Duration:
0:02 minutes