(0) Obligation:

Clauses:

even(s(s(X))) :- even(X).
even(0).
lte(s(X), s(Y)) :- lte(X, Y).
lte(0, Y).
goal :- ','(lte(X, s(s(s(s(0))))), even(X)).

Query: goal()

(1) PrologToPrologProblemTransformerProof (SOUND transformation)

Built Prolog problem from termination graph ICLP10.

(2) Obligation:

Clauses:

evenA(s(s(T13))) :- evenA(T13).
evenA(0).
lteB(s(s(s(0)))).
lteB(s(s(0))).
lteB(s(0)).
lteB(0).
goalC :- lteB(X22).
goalC :- ','(lteB(s(T7)), evenA(T7)).
goalC.

Query: goalC()

(3) PrologToPiTRSProof (SOUND transformation)

We use the technique of [TOCL09]. With regard to the inferred argument filtering the predicates were used in the following modes:
evenA_in: (b)
Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:

goalC_in_U2_(lteB_in_a(X22))
lteB_in_a(s(s(s(0)))) → lteB_out_a(s(s(s(0))))
lteB_in_a(s(s(0))) → lteB_out_a(s(s(0)))
lteB_in_a(s(0)) → lteB_out_a(s(0))
lteB_in_a(0) → lteB_out_a(0)
U2_(lteB_out_a(X22)) → goalC_out_
goalC_in_U3_(lteB_in_a(s(T7)))
U3_(lteB_out_a(s(T7))) → U4_(evenA_in_g(T7))
evenA_in_g(s(s(T13))) → U1_g(T13, evenA_in_g(T13))
evenA_in_g(0) → evenA_out_g(0)
U1_g(T13, evenA_out_g(T13)) → evenA_out_g(s(s(T13)))
U4_(evenA_out_g(T7)) → goalC_out_
goalC_in_goalC_out_

The argument filtering Pi contains the following mapping:
goalC_in_  =  goalC_in_
U2_(x1)  =  U2_(x1)
lteB_in_a(x1)  =  lteB_in_a
lteB_out_a(x1)  =  lteB_out_a(x1)
goalC_out_  =  goalC_out_
U3_(x1)  =  U3_(x1)
s(x1)  =  s(x1)
U4_(x1)  =  U4_(x1)
evenA_in_g(x1)  =  evenA_in_g(x1)
U1_g(x1, x2)  =  U1_g(x2)
0  =  0
evenA_out_g(x1)  =  evenA_out_g

Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog

(4) Obligation:

Pi-finite rewrite system:
The TRS R consists of the following rules:

goalC_in_U2_(lteB_in_a(X22))
lteB_in_a(s(s(s(0)))) → lteB_out_a(s(s(s(0))))
lteB_in_a(s(s(0))) → lteB_out_a(s(s(0)))
lteB_in_a(s(0)) → lteB_out_a(s(0))
lteB_in_a(0) → lteB_out_a(0)
U2_(lteB_out_a(X22)) → goalC_out_
goalC_in_U3_(lteB_in_a(s(T7)))
U3_(lteB_out_a(s(T7))) → U4_(evenA_in_g(T7))
evenA_in_g(s(s(T13))) → U1_g(T13, evenA_in_g(T13))
evenA_in_g(0) → evenA_out_g(0)
U1_g(T13, evenA_out_g(T13)) → evenA_out_g(s(s(T13)))
U4_(evenA_out_g(T7)) → goalC_out_
goalC_in_goalC_out_

The argument filtering Pi contains the following mapping:
goalC_in_  =  goalC_in_
U2_(x1)  =  U2_(x1)
lteB_in_a(x1)  =  lteB_in_a
lteB_out_a(x1)  =  lteB_out_a(x1)
goalC_out_  =  goalC_out_
U3_(x1)  =  U3_(x1)
s(x1)  =  s(x1)
U4_(x1)  =  U4_(x1)
evenA_in_g(x1)  =  evenA_in_g(x1)
U1_g(x1, x2)  =  U1_g(x2)
0  =  0
evenA_out_g(x1)  =  evenA_out_g

(5) DependencyPairsProof (EQUIVALENT transformation)

Using Dependency Pairs [AG00,LOPSTR] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:

GOALC_IN_U2_1(lteB_in_a(X22))
GOALC_IN_LTEB_IN_A(X22)
GOALC_IN_U3_1(lteB_in_a(s(T7)))
GOALC_IN_LTEB_IN_A(s(T7))
U3_1(lteB_out_a(s(T7))) → U4_1(evenA_in_g(T7))
U3_1(lteB_out_a(s(T7))) → EVENA_IN_G(T7)
EVENA_IN_G(s(s(T13))) → U1_G(T13, evenA_in_g(T13))
EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)

The TRS R consists of the following rules:

goalC_in_U2_(lteB_in_a(X22))
lteB_in_a(s(s(s(0)))) → lteB_out_a(s(s(s(0))))
lteB_in_a(s(s(0))) → lteB_out_a(s(s(0)))
lteB_in_a(s(0)) → lteB_out_a(s(0))
lteB_in_a(0) → lteB_out_a(0)
U2_(lteB_out_a(X22)) → goalC_out_
goalC_in_U3_(lteB_in_a(s(T7)))
U3_(lteB_out_a(s(T7))) → U4_(evenA_in_g(T7))
evenA_in_g(s(s(T13))) → U1_g(T13, evenA_in_g(T13))
evenA_in_g(0) → evenA_out_g(0)
U1_g(T13, evenA_out_g(T13)) → evenA_out_g(s(s(T13)))
U4_(evenA_out_g(T7)) → goalC_out_
goalC_in_goalC_out_

The argument filtering Pi contains the following mapping:
goalC_in_  =  goalC_in_
U2_(x1)  =  U2_(x1)
lteB_in_a(x1)  =  lteB_in_a
lteB_out_a(x1)  =  lteB_out_a(x1)
goalC_out_  =  goalC_out_
U3_(x1)  =  U3_(x1)
s(x1)  =  s(x1)
U4_(x1)  =  U4_(x1)
evenA_in_g(x1)  =  evenA_in_g(x1)
U1_g(x1, x2)  =  U1_g(x2)
0  =  0
evenA_out_g(x1)  =  evenA_out_g
GOALC_IN_  =  GOALC_IN_
U2_1(x1)  =  U2_1(x1)
LTEB_IN_A(x1)  =  LTEB_IN_A
U3_1(x1)  =  U3_1(x1)
U4_1(x1)  =  U4_1(x1)
EVENA_IN_G(x1)  =  EVENA_IN_G(x1)
U1_G(x1, x2)  =  U1_G(x2)

We have to consider all (P,R,Pi)-chains

(6) Obligation:

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

GOALC_IN_U2_1(lteB_in_a(X22))
GOALC_IN_LTEB_IN_A(X22)
GOALC_IN_U3_1(lteB_in_a(s(T7)))
GOALC_IN_LTEB_IN_A(s(T7))
U3_1(lteB_out_a(s(T7))) → U4_1(evenA_in_g(T7))
U3_1(lteB_out_a(s(T7))) → EVENA_IN_G(T7)
EVENA_IN_G(s(s(T13))) → U1_G(T13, evenA_in_g(T13))
EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)

The TRS R consists of the following rules:

goalC_in_U2_(lteB_in_a(X22))
lteB_in_a(s(s(s(0)))) → lteB_out_a(s(s(s(0))))
lteB_in_a(s(s(0))) → lteB_out_a(s(s(0)))
lteB_in_a(s(0)) → lteB_out_a(s(0))
lteB_in_a(0) → lteB_out_a(0)
U2_(lteB_out_a(X22)) → goalC_out_
goalC_in_U3_(lteB_in_a(s(T7)))
U3_(lteB_out_a(s(T7))) → U4_(evenA_in_g(T7))
evenA_in_g(s(s(T13))) → U1_g(T13, evenA_in_g(T13))
evenA_in_g(0) → evenA_out_g(0)
U1_g(T13, evenA_out_g(T13)) → evenA_out_g(s(s(T13)))
U4_(evenA_out_g(T7)) → goalC_out_
goalC_in_goalC_out_

The argument filtering Pi contains the following mapping:
goalC_in_  =  goalC_in_
U2_(x1)  =  U2_(x1)
lteB_in_a(x1)  =  lteB_in_a
lteB_out_a(x1)  =  lteB_out_a(x1)
goalC_out_  =  goalC_out_
U3_(x1)  =  U3_(x1)
s(x1)  =  s(x1)
U4_(x1)  =  U4_(x1)
evenA_in_g(x1)  =  evenA_in_g(x1)
U1_g(x1, x2)  =  U1_g(x2)
0  =  0
evenA_out_g(x1)  =  evenA_out_g
GOALC_IN_  =  GOALC_IN_
U2_1(x1)  =  U2_1(x1)
LTEB_IN_A(x1)  =  LTEB_IN_A
U3_1(x1)  =  U3_1(x1)
U4_1(x1)  =  U4_1(x1)
EVENA_IN_G(x1)  =  EVENA_IN_G(x1)
U1_G(x1, x2)  =  U1_G(x2)

We have to consider all (P,R,Pi)-chains

(7) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LOPSTR] contains 1 SCC with 7 less nodes.

(8) Obligation:

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

EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)

The TRS R consists of the following rules:

goalC_in_U2_(lteB_in_a(X22))
lteB_in_a(s(s(s(0)))) → lteB_out_a(s(s(s(0))))
lteB_in_a(s(s(0))) → lteB_out_a(s(s(0)))
lteB_in_a(s(0)) → lteB_out_a(s(0))
lteB_in_a(0) → lteB_out_a(0)
U2_(lteB_out_a(X22)) → goalC_out_
goalC_in_U3_(lteB_in_a(s(T7)))
U3_(lteB_out_a(s(T7))) → U4_(evenA_in_g(T7))
evenA_in_g(s(s(T13))) → U1_g(T13, evenA_in_g(T13))
evenA_in_g(0) → evenA_out_g(0)
U1_g(T13, evenA_out_g(T13)) → evenA_out_g(s(s(T13)))
U4_(evenA_out_g(T7)) → goalC_out_
goalC_in_goalC_out_

The argument filtering Pi contains the following mapping:
goalC_in_  =  goalC_in_
U2_(x1)  =  U2_(x1)
lteB_in_a(x1)  =  lteB_in_a
lteB_out_a(x1)  =  lteB_out_a(x1)
goalC_out_  =  goalC_out_
U3_(x1)  =  U3_(x1)
s(x1)  =  s(x1)
U4_(x1)  =  U4_(x1)
evenA_in_g(x1)  =  evenA_in_g(x1)
U1_g(x1, x2)  =  U1_g(x2)
0  =  0
evenA_out_g(x1)  =  evenA_out_g
EVENA_IN_G(x1)  =  EVENA_IN_G(x1)

We have to consider all (P,R,Pi)-chains

(9) UsableRulesProof (EQUIVALENT transformation)

For (infinitary) constructor rewriting [LOPSTR] we can delete all non-usable rules from R.

(10) Obligation:

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

EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)

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

(11) PiDPToQDPProof (EQUIVALENT transformation)

Transforming (infinitary) constructor rewriting Pi-DP problem [LOPSTR] into ordinary QDP problem [LPAR04] by application of Pi.

(12) Obligation:

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

EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)

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

(13) 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:

  • EVENA_IN_G(s(s(T13))) → EVENA_IN_G(T13)
    The graph contains the following edges 1 > 1

(14) YES