Left Termination of the query pattern p_in_1(g) w.r.t. the given Prolog program could successfully be proven:



Prolog
  ↳ PrologToPiTRSProof

Clauses:

p(0).
p(s(X)) :- ','(geq(X, Y), p(Y)).
geq(X, X).
geq(s(X), Y) :- geq(X, Y).

Queries:

p(g).

We use the technique of [30]. With regard to the inferred argument filtering the predicates were used in the following modes:
p_in: (b)
geq_in: (b,f)
Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)

Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog



↳ Prolog
  ↳ PrologToPiTRSProof
PiTRS
      ↳ DependencyPairsProof

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

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)


Using Dependency Pairs [1,30] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:

P_IN_G(s(X)) → U1_G(X, geq_in_ga(X, Y))
P_IN_G(s(X)) → GEQ_IN_GA(X, Y)
GEQ_IN_GA(s(X), Y) → U3_GA(X, Y, geq_in_ga(X, Y))
GEQ_IN_GA(s(X), Y) → GEQ_IN_GA(X, Y)
U1_G(X, geq_out_ga(X, Y)) → U2_G(X, p_in_g(Y))
U1_G(X, geq_out_ga(X, Y)) → P_IN_G(Y)

The TRS R consists of the following rules:

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)
U2_G(x1, x2)  =  U2_G(x2)
P_IN_G(x1)  =  P_IN_G(x1)
GEQ_IN_GA(x1, x2)  =  GEQ_IN_GA(x1)
U3_GA(x1, x2, x3)  =  U3_GA(x3)
U1_G(x1, x2)  =  U1_G(x2)

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

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
PiDP
          ↳ DependencyGraphProof

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

P_IN_G(s(X)) → U1_G(X, geq_in_ga(X, Y))
P_IN_G(s(X)) → GEQ_IN_GA(X, Y)
GEQ_IN_GA(s(X), Y) → U3_GA(X, Y, geq_in_ga(X, Y))
GEQ_IN_GA(s(X), Y) → GEQ_IN_GA(X, Y)
U1_G(X, geq_out_ga(X, Y)) → U2_G(X, p_in_g(Y))
U1_G(X, geq_out_ga(X, Y)) → P_IN_G(Y)

The TRS R consists of the following rules:

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)
U2_G(x1, x2)  =  U2_G(x2)
P_IN_G(x1)  =  P_IN_G(x1)
GEQ_IN_GA(x1, x2)  =  GEQ_IN_GA(x1)
U3_GA(x1, x2, x3)  =  U3_GA(x3)
U1_G(x1, x2)  =  U1_G(x2)

We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 2 SCCs with 3 less nodes.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
PiDP
                ↳ UsableRulesProof
              ↳ PiDP

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

GEQ_IN_GA(s(X), Y) → GEQ_IN_GA(X, Y)

The TRS R consists of the following rules:

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)
GEQ_IN_GA(x1, x2)  =  GEQ_IN_GA(x1)

We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
                ↳ UsableRulesProof
PiDP
                    ↳ PiDPToQDPProof
              ↳ PiDP

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

GEQ_IN_GA(s(X), Y) → GEQ_IN_GA(X, Y)

R is empty.
The argument filtering Pi contains the following mapping:
s(x1)  =  s(x1)
GEQ_IN_GA(x1, x2)  =  GEQ_IN_GA(x1)

We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
                ↳ UsableRulesProof
                  ↳ PiDP
                    ↳ PiDPToQDPProof
QDP
                        ↳ QDPSizeChangeProof
              ↳ PiDP

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

GEQ_IN_GA(s(X)) → GEQ_IN_GA(X)

R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] 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:



↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
PiDP
                ↳ UsableRulesProof

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

U1_G(X, geq_out_ga(X, Y)) → P_IN_G(Y)
P_IN_G(s(X)) → U1_G(X, geq_in_ga(X, Y))

The TRS R consists of the following rules:

p_in_g(0) → p_out_g(0)
p_in_g(s(X)) → U1_g(X, geq_in_ga(X, Y))
geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)
U1_g(X, geq_out_ga(X, Y)) → U2_g(X, p_in_g(Y))
U2_g(X, p_out_g(Y)) → p_out_g(s(X))

The argument filtering Pi contains the following mapping:
p_in_g(x1)  =  p_in_g(x1)
0  =  0
p_out_g(x1)  =  p_out_g
s(x1)  =  s(x1)
U1_g(x1, x2)  =  U1_g(x2)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
U2_g(x1, x2)  =  U2_g(x2)
P_IN_G(x1)  =  P_IN_G(x1)
U1_G(x1, x2)  =  U1_G(x2)

We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof
PiDP
                    ↳ PiDPToQDPProof

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

U1_G(X, geq_out_ga(X, Y)) → P_IN_G(Y)
P_IN_G(s(X)) → U1_G(X, geq_in_ga(X, Y))

The TRS R consists of the following rules:

geq_in_ga(X, X) → geq_out_ga(X, X)
geq_in_ga(s(X), Y) → U3_ga(X, Y, geq_in_ga(X, Y))
U3_ga(X, Y, geq_out_ga(X, Y)) → geq_out_ga(s(X), Y)

The argument filtering Pi contains the following mapping:
s(x1)  =  s(x1)
geq_in_ga(x1, x2)  =  geq_in_ga(x1)
geq_out_ga(x1, x2)  =  geq_out_ga(x2)
U3_ga(x1, x2, x3)  =  U3_ga(x3)
P_IN_G(x1)  =  P_IN_G(x1)
U1_G(x1, x2)  =  U1_G(x2)

We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof
                  ↳ PiDP
                    ↳ PiDPToQDPProof
QDP
                        ↳ UsableRulesReductionPairsProof

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

P_IN_G(s(X)) → U1_G(geq_in_ga(X))
U1_G(geq_out_ga(Y)) → P_IN_G(Y)

The TRS R consists of the following rules:

geq_in_ga(X) → geq_out_ga(X)
geq_in_ga(s(X)) → U3_ga(geq_in_ga(X))
U3_ga(geq_out_ga(Y)) → geq_out_ga(Y)

The set Q consists of the following terms:

geq_in_ga(x0)
U3_ga(x0)

We have to consider all (P,Q,R)-chains.
By using the usable rules with reduction pair processor [15] with a polynomial ordering [25], all dependency pairs and the corresponding usable rules [17] can be oriented non-strictly. All non-usable rules are removed, and those dependency pairs and usable rules that have been oriented strictly or contain non-usable symbols in their left-hand side are removed as well.

The following dependency pairs can be deleted:

P_IN_G(s(X)) → U1_G(geq_in_ga(X))
The following rules are removed from R:

geq_in_ga(s(X)) → U3_ga(geq_in_ga(X))
U3_ga(geq_out_ga(Y)) → geq_out_ga(Y)
Used ordering: POLO with Polynomial interpretation [25]:

POL(P_IN_G(x1)) = x1   
POL(U1_G(x1)) = 2·x1   
POL(U3_ga(x1)) = 1 + x1   
POL(geq_in_ga(x1)) = x1   
POL(geq_out_ga(x1)) = x1   
POL(s(x1)) = 1 + 2·x1   



↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof
                  ↳ PiDP
                    ↳ PiDPToQDPProof
                      ↳ QDP
                        ↳ UsableRulesReductionPairsProof
QDP
                            ↳ DependencyGraphProof

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

U1_G(geq_out_ga(Y)) → P_IN_G(Y)

The TRS R consists of the following rules:

geq_in_ga(X) → geq_out_ga(X)

The set Q consists of the following terms:

geq_in_ga(x0)
U3_ga(x0)

We have to consider all (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 0 SCCs with 1 less node.