Termination Proof using AProVE

Term Rewriting System R:
[X, Y, X1, X2]
fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

Termination of R to be shown.

     ↳Dependency Pair Analysis

R contains the following Dependency Pairs:

FACT(X) -> IF(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
FACT(X) -> ZERO(X)
ADD(s(X), Y) -> S(add(X, Y))
ADD(s(X), Y) -> ADD(X, Y)
PROD(s(X), Y) -> ADD(Y, prod(X, Y))
PROD(s(X), Y) -> PROD(X, Y)
IF(true, X, Y) -> ACTIVATE(X)
IF(false, X, Y) -> ACTIVATE(Y)
ACTIVATE(n_{_s}(X)) -> S(activate(X))
ACTIVATE(n_{_s}(X)) -> ACTIVATE(X)
ACTIVATE(n_₀) -> 0'
ACTIVATE(n_{_prod}(X1, X2)) -> PROD(activate(X1), activate(X2))
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X1)
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X2)
ACTIVATE(n_{_fact}(X)) -> FACT(activate(X))
ACTIVATE(n_{_fact}(X)) -> ACTIVATE(X)
ACTIVATE(n_{_p}(X)) -> P(activate(X))
ACTIVATE(n_{_p}(X)) -> ACTIVATE(X)

Furthermore, R contains three SCCs.

     ↳DPs

       →DP Problem 1

         ↳Size-Change Principle

       →DP Problem 2

         ↳SCP

       →DP Problem 3

         ↳Inst

Dependency Pair:

ADD(s(X), Y) -> ADD(X, Y)

Rules:

fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

We number the DPs as follows:

ADD(s(X), Y) -> ADD(X, Y)

and get the following Size-Change Graph(s):

{1}	,	{1}
1	>	1
2	=	2

which lead(s) to this/these maximal multigraph(s):

{1}	,	{1}
1	>	1
2	=	2

D_P: empty set
Oriented Rules: none

We used the order Homeomorphic Embedding Order with Non-Strict Precedence.

trivial

with Argument Filtering System:

s(x₁) -> s(x₁)

We obtain no new DP problems.

     ↳DPs

       →DP Problem 1

         ↳SCP

       →DP Problem 2

         ↳Size-Change Principle

       →DP Problem 3

         ↳Inst

Dependency Pair:

PROD(s(X), Y) -> PROD(X, Y)

Rules:

fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

We number the DPs as follows:

PROD(s(X), Y) -> PROD(X, Y)

and get the following Size-Change Graph(s):

{1}	,	{1}
1	>	1
2	=	2

which lead(s) to this/these maximal multigraph(s):

{1}	,	{1}
1	>	1
2	=	2

D_P: empty set
Oriented Rules: none

We used the order Homeomorphic Embedding Order with Non-Strict Precedence.

trivial

with Argument Filtering System:

s(x₁) -> s(x₁)

We obtain no new DP problems.

     ↳DPs

       →DP Problem 1

         ↳SCP

       →DP Problem 2

         ↳SCP

       →DP Problem 3

         ↳Instantiation Transformation

Dependency Pairs:

IF(false, X, Y) -> ACTIVATE(Y)
ACTIVATE(n_{_p}(X)) -> ACTIVATE(X)
ACTIVATE(n_{_fact}(X)) -> ACTIVATE(X)
ACTIVATE(n_{_fact}(X)) -> FACT(activate(X))
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X2)
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X1)
ACTIVATE(n_{_s}(X)) -> ACTIVATE(X)
IF(true, X, Y) -> ACTIVATE(X)
FACT(X) -> IF(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))

Rules:

fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

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

IF(true, X, Y) -> ACTIVATE(X)

one new Dependency Pair is created:

IF(true, n_{_s}(n_₀), n_{_prod}(X'0, n_{_fact}(n_{_p}(X''')))) -> ACTIVATE(n_{_s}(n_₀))

The transformation is resulting in one new DP problem:

     ↳DPs

       →DP Problem 1

         ↳SCP

       →DP Problem 2

         ↳SCP

       →DP Problem 3

         ↳Inst

           →DP Problem 4

             ↳Instantiation Transformation

Dependency Pairs:

ACTIVATE(n_{_p}(X)) -> ACTIVATE(X)
ACTIVATE(n_{_fact}(X)) -> ACTIVATE(X)
IF(true, n_{_s}(n_₀), n_{_prod}(X'0, n_{_fact}(n_{_p}(X''')))) -> ACTIVATE(n_{_s}(n_₀))
FACT(X) -> IF(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
ACTIVATE(n_{_fact}(X)) -> FACT(activate(X))
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X2)
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X1)
ACTIVATE(n_{_s}(X)) -> ACTIVATE(X)
IF(false, X, Y) -> ACTIVATE(Y)

Rules:

fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

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

IF(false, X, Y) -> ACTIVATE(Y)

one new Dependency Pair is created:

IF(false, n_{_s}(n_₀), n_{_prod}(X'0, n_{_fact}(n_{_p}(X''')))) -> ACTIVATE(n_{_prod}(X'0, n_{_fact}(n_{_p}(X'''))))

The transformation is resulting in one new DP problem:

     ↳DPs

       →DP Problem 1

         ↳SCP

       →DP Problem 2

         ↳SCP

       →DP Problem 3

         ↳Inst

           →DP Problem 4

             ↳Inst

...

               →DP Problem 5

                 ↳Remaining Obligation(s)

The following remains to be proven:
Dependency Pairs:

ACTIVATE(n_{_fact}(X)) -> ACTIVATE(X)
IF(false, n_{_s}(n_₀), n_{_prod}(X'0, n_{_fact}(n_{_p}(X''')))) -> ACTIVATE(n_{_prod}(X'0, n_{_fact}(n_{_p}(X'''))))
IF(true, n_{_s}(n_₀), n_{_prod}(X'0, n_{_fact}(n_{_p}(X''')))) -> ACTIVATE(n_{_s}(n_₀))
FACT(X) -> IF(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
ACTIVATE(n_{_fact}(X)) -> FACT(activate(X))
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X2)
ACTIVATE(n_{_prod}(X1, X2)) -> ACTIVATE(X1)
ACTIVATE(n_{_s}(X)) -> ACTIVATE(X)
ACTIVATE(n_{_p}(X)) -> ACTIVATE(X)

Rules:

fact(X) -> if(zero(X), n_{_s}(n_₀), n_{_prod}(X, n_{_fact}(n_{_p}(X))))
fact(X) -> n_{_fact}(X)
add(0, X) -> X
add(s(X), Y) -> s(add(X, Y))
prod(0, X) -> 0
prod(s(X), Y) -> add(Y, prod(X, Y))
prod(X1, X2) -> n_{_prod}(X1, X2)
if(true, X, Y) -> activate(X)
if(false, X, Y) -> activate(Y)
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
p(X) -> n_{_p}(X)
s(X) -> n_{_s}(X)
0 -> n_₀
activate(n_{_s}(X)) -> s(activate(X))
activate(n_₀) -> 0
activate(n_{_prod}(X1, X2)) -> prod(activate(X1), activate(X2))
activate(n_{_fact}(X)) -> fact(activate(X))
activate(n_{_p}(X)) -> p(activate(X))
activate(X) -> X

The Proof could not be continued due to a Timeout.
Termination of R could not be shown.
Duration:
1:00 minutes