Left Termination of the query pattern perm_in_2(g, a) w.r.t. the given Prolog program could successfully be proven:



Prolog
  ↳ PrologToPiTRSProof

Clauses:

ap1(nil, X, X).
ap1(cons(H, X), Y, cons(H, Z)) :- ap1(X, Y, Z).
ap2(nil, X, X).
ap2(cons(H, X), Y, cons(H, Z)) :- ap2(X, Y, Z).
perm(nil, nil).
perm(Xs, cons(X, Ys)) :- ','(ap1(X1s, cons(X, X2s), Xs), ','(ap2(X1s, X2s, Zs), perm(Zs, Ys))).

Queries:

perm(g,a).

We use the technique of [30]. With regard to the inferred argument filtering the predicates were used in the following modes:
perm_in: (b,f)
ap1_in: (f,f,b)
ap2_in: (b,b,f)
Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)

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:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)


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

PERM_IN_GA(Xs, cons(X, Ys)) → U3_GA(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
PERM_IN_GA(Xs, cons(X, Ys)) → AP1_IN_AAG(X1s, cons(X, X2s), Xs)
AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → U1_AAG(H, X, Y, Z, ap1_in_aag(X, Y, Z))
AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → AP1_IN_AAG(X, Y, Z)
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_GA(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → AP2_IN_GGA(X1s, X2s, Zs)
AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → U2_GGA(H, X, Y, Z, ap2_in_gga(X, Y, Z))
AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → AP2_IN_GGA(X, Y, Z)
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_GA(Xs, X, Ys, perm_in_ga(Zs, Ys))
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → PERM_IN_GA(Zs, Ys)

The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)
U5_GA(x1, x2, x3, x4)  =  U5_GA(x4)
AP1_IN_AAG(x1, x2, x3)  =  AP1_IN_AAG(x3)
U2_GGA(x1, x2, x3, x4, x5)  =  U2_GGA(x5)
AP2_IN_GGA(x1, x2, x3)  =  AP2_IN_GGA(x1, x2)
U1_AAG(x1, x2, x3, x4, x5)  =  U1_AAG(x5)
U4_GA(x1, x2, x3, x4, x5, x6)  =  U4_GA(x6)
U3_GA(x1, x2, x3, x4)  =  U3_GA(x4)
PERM_IN_GA(x1, x2)  =  PERM_IN_GA(x1)

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:

PERM_IN_GA(Xs, cons(X, Ys)) → U3_GA(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
PERM_IN_GA(Xs, cons(X, Ys)) → AP1_IN_AAG(X1s, cons(X, X2s), Xs)
AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → U1_AAG(H, X, Y, Z, ap1_in_aag(X, Y, Z))
AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → AP1_IN_AAG(X, Y, Z)
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_GA(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → AP2_IN_GGA(X1s, X2s, Zs)
AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → U2_GGA(H, X, Y, Z, ap2_in_gga(X, Y, Z))
AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → AP2_IN_GGA(X, Y, Z)
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_GA(Xs, X, Ys, perm_in_ga(Zs, Ys))
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → PERM_IN_GA(Zs, Ys)

The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)
U5_GA(x1, x2, x3, x4)  =  U5_GA(x4)
AP1_IN_AAG(x1, x2, x3)  =  AP1_IN_AAG(x3)
U2_GGA(x1, x2, x3, x4, x5)  =  U2_GGA(x5)
AP2_IN_GGA(x1, x2, x3)  =  AP2_IN_GGA(x1, x2)
U1_AAG(x1, x2, x3, x4, x5)  =  U1_AAG(x5)
U4_GA(x1, x2, x3, x4, x5, x6)  =  U4_GA(x6)
U3_GA(x1, x2, x3, x4)  =  U3_GA(x4)
PERM_IN_GA(x1, x2)  =  PERM_IN_GA(x1)

We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 3 SCCs with 5 less nodes.

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

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

AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → AP2_IN_GGA(X, Y, Z)

The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)
AP2_IN_GGA(x1, x2, x3)  =  AP2_IN_GGA(x1, 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
                ↳ UsableRulesProof
PiDP
                    ↳ PiDPToQDPProof
              ↳ PiDP
              ↳ PiDP

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

AP2_IN_GGA(cons(H, X), Y, cons(H, Z)) → AP2_IN_GGA(X, Y, Z)

R is empty.
The argument filtering Pi contains the following mapping:
cons(x1, x2)  =  cons(x2)
AP2_IN_GGA(x1, x2, x3)  =  AP2_IN_GGA(x1, 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
                ↳ UsableRulesProof
                  ↳ PiDP
                    ↳ PiDPToQDPProof
QDP
                        ↳ QDPSizeChangeProof
              ↳ PiDP
              ↳ PiDP

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

AP2_IN_GGA(cons(X), Y) → AP2_IN_GGA(X, Y)

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
              ↳ PiDP

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

AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → AP1_IN_AAG(X, Y, Z)

The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)
AP1_IN_AAG(x1, x2, x3)  =  AP1_IN_AAG(x3)

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
              ↳ PiDP

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

AP1_IN_AAG(cons(H, X), Y, cons(H, Z)) → AP1_IN_AAG(X, Y, Z)

R is empty.
The argument filtering Pi contains the following mapping:
cons(x1, x2)  =  cons(x2)
AP1_IN_AAG(x1, x2, x3)  =  AP1_IN_AAG(x3)

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
                        ↳ QDPSizeChangeProof
              ↳ PiDP

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

AP1_IN_AAG(cons(Z)) → AP1_IN_AAG(Z)

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
PiDP
                ↳ UsableRulesProof

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

PERM_IN_GA(Xs, cons(X, Ys)) → U3_GA(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → PERM_IN_GA(Zs, Ys)
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_GA(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))

The TRS R consists of the following rules:

perm_in_ga(nil, nil) → perm_out_ga(nil, nil)
perm_in_ga(Xs, cons(X, Ys)) → U3_ga(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U3_ga(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_ga(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))
U4_ga(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → U5_ga(Xs, X, Ys, perm_in_ga(Zs, Ys))
U5_ga(Xs, X, Ys, perm_out_ga(Zs, Ys)) → perm_out_ga(Xs, cons(X, Ys))

The argument filtering Pi contains the following mapping:
perm_in_ga(x1, x2)  =  perm_in_ga(x1)
nil  =  nil
perm_out_ga(x1, x2)  =  perm_out_ga(x2)
U3_ga(x1, x2, x3, x4)  =  U3_ga(x4)
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
U4_ga(x1, x2, x3, x4, x5, x6)  =  U4_ga(x6)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U5_ga(x1, x2, x3, x4)  =  U5_ga(x4)
U4_GA(x1, x2, x3, x4, x5, x6)  =  U4_GA(x6)
U3_GA(x1, x2, x3, x4)  =  U3_GA(x4)
PERM_IN_GA(x1, x2)  =  PERM_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
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof
PiDP
                    ↳ PiDPToQDPProof

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

PERM_IN_GA(Xs, cons(X, Ys)) → U3_GA(Xs, X, Ys, ap1_in_aag(X1s, cons(X, X2s), Xs))
U4_GA(Xs, X, Ys, X1s, X2s, ap2_out_gga(X1s, X2s, Zs)) → PERM_IN_GA(Zs, Ys)
U3_GA(Xs, X, Ys, ap1_out_aag(X1s, cons(X, X2s), Xs)) → U4_GA(Xs, X, Ys, X1s, X2s, ap2_in_gga(X1s, X2s, Zs))

The TRS R consists of the following rules:

ap1_in_aag(nil, X, X) → ap1_out_aag(nil, X, X)
ap1_in_aag(cons(H, X), Y, cons(H, Z)) → U1_aag(H, X, Y, Z, ap1_in_aag(X, Y, Z))
ap2_in_gga(nil, X, X) → ap2_out_gga(nil, X, X)
ap2_in_gga(cons(H, X), Y, cons(H, Z)) → U2_gga(H, X, Y, Z, ap2_in_gga(X, Y, Z))
U1_aag(H, X, Y, Z, ap1_out_aag(X, Y, Z)) → ap1_out_aag(cons(H, X), Y, cons(H, Z))
U2_gga(H, X, Y, Z, ap2_out_gga(X, Y, Z)) → ap2_out_gga(cons(H, X), Y, cons(H, Z))

The argument filtering Pi contains the following mapping:
nil  =  nil
ap1_in_aag(x1, x2, x3)  =  ap1_in_aag(x3)
cons(x1, x2)  =  cons(x2)
ap1_out_aag(x1, x2, x3)  =  ap1_out_aag(x1, x2)
U1_aag(x1, x2, x3, x4, x5)  =  U1_aag(x5)
ap2_in_gga(x1, x2, x3)  =  ap2_in_gga(x1, x2)
ap2_out_gga(x1, x2, x3)  =  ap2_out_gga(x3)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x5)
U4_GA(x1, x2, x3, x4, x5, x6)  =  U4_GA(x6)
U3_GA(x1, x2, x3, x4)  =  U3_GA(x4)
PERM_IN_GA(x1, x2)  =  PERM_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
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof
                  ↳ PiDP
                    ↳ PiDPToQDPProof
QDP
                        ↳ RuleRemovalProof

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

U3_GA(ap1_out_aag(X1s, cons(X2s))) → U4_GA(ap2_in_gga(X1s, X2s))
U4_GA(ap2_out_gga(Zs)) → PERM_IN_GA(Zs)
PERM_IN_GA(Xs) → U3_GA(ap1_in_aag(Xs))

The TRS R consists of the following rules:

ap1_in_aag(X) → ap1_out_aag(nil, X)
ap1_in_aag(cons(Z)) → U1_aag(ap1_in_aag(Z))
ap2_in_gga(nil, X) → ap2_out_gga(X)
ap2_in_gga(cons(X), Y) → U2_gga(ap2_in_gga(X, Y))
U1_aag(ap1_out_aag(X, Y)) → ap1_out_aag(cons(X), Y)
U2_gga(ap2_out_gga(Z)) → ap2_out_gga(cons(Z))

The set Q consists of the following terms:

ap1_in_aag(x0)
ap2_in_gga(x0, x1)
U1_aag(x0)
U2_gga(x0)

We have to consider all (P,Q,R)-chains.
By using the rule removal processor [15] with the following polynomial ordering [25], at least one Dependency Pair or term rewrite system rule of this QDP problem can be strictly oriented.
Strictly oriented dependency pairs:

U3_GA(ap1_out_aag(X1s, cons(X2s))) → U4_GA(ap2_in_gga(X1s, X2s))


Used ordering: POLO with Polynomial interpretation [25]:

POL(PERM_IN_GA(x1)) = 2·x1   
POL(U1_aag(x1)) = 2 + x1   
POL(U2_gga(x1)) = 1 + x1   
POL(U3_GA(x1)) = x1   
POL(U4_GA(x1)) = 2·x1   
POL(ap1_in_aag(x1)) = 2·x1   
POL(ap1_out_aag(x1, x2)) = 2·x1 + 2·x2   
POL(ap2_in_gga(x1, x2)) = x1 + x2   
POL(ap2_out_gga(x1)) = x1   
POL(cons(x1)) = 1 + x1   
POL(nil) = 0   



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

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

U4_GA(ap2_out_gga(Zs)) → PERM_IN_GA(Zs)
PERM_IN_GA(Xs) → U3_GA(ap1_in_aag(Xs))

The TRS R consists of the following rules:

ap1_in_aag(X) → ap1_out_aag(nil, X)
ap1_in_aag(cons(Z)) → U1_aag(ap1_in_aag(Z))
ap2_in_gga(nil, X) → ap2_out_gga(X)
ap2_in_gga(cons(X), Y) → U2_gga(ap2_in_gga(X, Y))
U1_aag(ap1_out_aag(X, Y)) → ap1_out_aag(cons(X), Y)
U2_gga(ap2_out_gga(Z)) → ap2_out_gga(cons(Z))

The set Q consists of the following terms:

ap1_in_aag(x0)
ap2_in_gga(x0, x1)
U1_aag(x0)
U2_gga(x0)

We have to consider all (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 0 SCCs with 2 less nodes.