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



PROLOG
  ↳ PrologToPiTRSProof

f3({}0, RES, RES).
f3(.2(Head, Tail), X, RES) :- g4(Tail, X, .2(Head, Tail), RES).
g4(A, B, C, RES) :- f3(A, .2(B, C), RES).


With regard to the inferred argument filtering the predicates were used in the following modes:
f3: (b,b,f)
g4: (b,b,b,f)
Transforming PROLOG into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:


f_3_in_gga3([]_0, RES, RES) -> f_3_out_gga3([]_0, RES, RES)
f_3_in_gga3(._22(Head, Tail), X, RES) -> if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
g_4_in_ggga4(A, B, C, RES) -> if_g_4_in_1_ggga5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
if_g_4_in_1_ggga5(A, B, C, RES, f_3_out_gga3(A, ._22(B, C), RES)) -> g_4_out_ggga4(A, B, C, RES)
if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_out_ggga4(Tail, X, ._22(Head, Tail), RES)) -> f_3_out_gga3(._22(Head, Tail), X, RES)

The argument filtering Pi contains the following mapping:
f_3_in_gga3(x1, x2, x3)  =  f_3_in_gga2(x1, x2)
[]_0  =  []_0
._22(x1, x2)  =  ._22(x1, x2)
f_3_out_gga3(x1, x2, x3)  =  f_3_out_gga1(x3)
if_f_3_in_1_gga5(x1, x2, x3, x4, x5)  =  if_f_3_in_1_gga1(x5)
g_4_in_ggga4(x1, x2, x3, x4)  =  g_4_in_ggga3(x1, x2, x3)
if_g_4_in_1_ggga5(x1, x2, x3, x4, x5)  =  if_g_4_in_1_ggga1(x5)
g_4_out_ggga4(x1, x2, x3, x4)  =  g_4_out_ggga1(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:

f_3_in_gga3([]_0, RES, RES) -> f_3_out_gga3([]_0, RES, RES)
f_3_in_gga3(._22(Head, Tail), X, RES) -> if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
g_4_in_ggga4(A, B, C, RES) -> if_g_4_in_1_ggga5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
if_g_4_in_1_ggga5(A, B, C, RES, f_3_out_gga3(A, ._22(B, C), RES)) -> g_4_out_ggga4(A, B, C, RES)
if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_out_ggga4(Tail, X, ._22(Head, Tail), RES)) -> f_3_out_gga3(._22(Head, Tail), X, RES)

The argument filtering Pi contains the following mapping:
f_3_in_gga3(x1, x2, x3)  =  f_3_in_gga2(x1, x2)
[]_0  =  []_0
._22(x1, x2)  =  ._22(x1, x2)
f_3_out_gga3(x1, x2, x3)  =  f_3_out_gga1(x3)
if_f_3_in_1_gga5(x1, x2, x3, x4, x5)  =  if_f_3_in_1_gga1(x5)
g_4_in_ggga4(x1, x2, x3, x4)  =  g_4_in_ggga3(x1, x2, x3)
if_g_4_in_1_ggga5(x1, x2, x3, x4, x5)  =  if_g_4_in_1_ggga1(x5)
g_4_out_ggga4(x1, x2, x3, x4)  =  g_4_out_ggga1(x4)


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

F_3_IN_GGA3(._22(Head, Tail), X, RES) -> IF_F_3_IN_1_GGA5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
F_3_IN_GGA3(._22(Head, Tail), X, RES) -> G_4_IN_GGGA4(Tail, X, ._22(Head, Tail), RES)
G_4_IN_GGGA4(A, B, C, RES) -> IF_G_4_IN_1_GGGA5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
G_4_IN_GGGA4(A, B, C, RES) -> F_3_IN_GGA3(A, ._22(B, C), RES)

The TRS R consists of the following rules:

f_3_in_gga3([]_0, RES, RES) -> f_3_out_gga3([]_0, RES, RES)
f_3_in_gga3(._22(Head, Tail), X, RES) -> if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
g_4_in_ggga4(A, B, C, RES) -> if_g_4_in_1_ggga5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
if_g_4_in_1_ggga5(A, B, C, RES, f_3_out_gga3(A, ._22(B, C), RES)) -> g_4_out_ggga4(A, B, C, RES)
if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_out_ggga4(Tail, X, ._22(Head, Tail), RES)) -> f_3_out_gga3(._22(Head, Tail), X, RES)

The argument filtering Pi contains the following mapping:
f_3_in_gga3(x1, x2, x3)  =  f_3_in_gga2(x1, x2)
[]_0  =  []_0
._22(x1, x2)  =  ._22(x1, x2)
f_3_out_gga3(x1, x2, x3)  =  f_3_out_gga1(x3)
if_f_3_in_1_gga5(x1, x2, x3, x4, x5)  =  if_f_3_in_1_gga1(x5)
g_4_in_ggga4(x1, x2, x3, x4)  =  g_4_in_ggga3(x1, x2, x3)
if_g_4_in_1_ggga5(x1, x2, x3, x4, x5)  =  if_g_4_in_1_ggga1(x5)
g_4_out_ggga4(x1, x2, x3, x4)  =  g_4_out_ggga1(x4)
G_4_IN_GGGA4(x1, x2, x3, x4)  =  G_4_IN_GGGA3(x1, x2, x3)
F_3_IN_GGA3(x1, x2, x3)  =  F_3_IN_GGA2(x1, x2)
IF_F_3_IN_1_GGA5(x1, x2, x3, x4, x5)  =  IF_F_3_IN_1_GGA1(x5)
IF_G_4_IN_1_GGGA5(x1, x2, x3, x4, x5)  =  IF_G_4_IN_1_GGGA1(x5)

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:

F_3_IN_GGA3(._22(Head, Tail), X, RES) -> IF_F_3_IN_1_GGA5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
F_3_IN_GGA3(._22(Head, Tail), X, RES) -> G_4_IN_GGGA4(Tail, X, ._22(Head, Tail), RES)
G_4_IN_GGGA4(A, B, C, RES) -> IF_G_4_IN_1_GGGA5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
G_4_IN_GGGA4(A, B, C, RES) -> F_3_IN_GGA3(A, ._22(B, C), RES)

The TRS R consists of the following rules:

f_3_in_gga3([]_0, RES, RES) -> f_3_out_gga3([]_0, RES, RES)
f_3_in_gga3(._22(Head, Tail), X, RES) -> if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
g_4_in_ggga4(A, B, C, RES) -> if_g_4_in_1_ggga5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
if_g_4_in_1_ggga5(A, B, C, RES, f_3_out_gga3(A, ._22(B, C), RES)) -> g_4_out_ggga4(A, B, C, RES)
if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_out_ggga4(Tail, X, ._22(Head, Tail), RES)) -> f_3_out_gga3(._22(Head, Tail), X, RES)

The argument filtering Pi contains the following mapping:
f_3_in_gga3(x1, x2, x3)  =  f_3_in_gga2(x1, x2)
[]_0  =  []_0
._22(x1, x2)  =  ._22(x1, x2)
f_3_out_gga3(x1, x2, x3)  =  f_3_out_gga1(x3)
if_f_3_in_1_gga5(x1, x2, x3, x4, x5)  =  if_f_3_in_1_gga1(x5)
g_4_in_ggga4(x1, x2, x3, x4)  =  g_4_in_ggga3(x1, x2, x3)
if_g_4_in_1_ggga5(x1, x2, x3, x4, x5)  =  if_g_4_in_1_ggga1(x5)
g_4_out_ggga4(x1, x2, x3, x4)  =  g_4_out_ggga1(x4)
G_4_IN_GGGA4(x1, x2, x3, x4)  =  G_4_IN_GGGA3(x1, x2, x3)
F_3_IN_GGA3(x1, x2, x3)  =  F_3_IN_GGA2(x1, x2)
IF_F_3_IN_1_GGA5(x1, x2, x3, x4, x5)  =  IF_F_3_IN_1_GGA1(x5)
IF_G_4_IN_1_GGGA5(x1, x2, x3, x4, x5)  =  IF_G_4_IN_1_GGGA1(x5)

We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph contains 1 SCC with 2 less nodes.

↳ PROLOG
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
PiDP
              ↳ UsableRulesProof

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

F_3_IN_GGA3(._22(Head, Tail), X, RES) -> G_4_IN_GGGA4(Tail, X, ._22(Head, Tail), RES)
G_4_IN_GGGA4(A, B, C, RES) -> F_3_IN_GGA3(A, ._22(B, C), RES)

The TRS R consists of the following rules:

f_3_in_gga3([]_0, RES, RES) -> f_3_out_gga3([]_0, RES, RES)
f_3_in_gga3(._22(Head, Tail), X, RES) -> if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_in_ggga4(Tail, X, ._22(Head, Tail), RES))
g_4_in_ggga4(A, B, C, RES) -> if_g_4_in_1_ggga5(A, B, C, RES, f_3_in_gga3(A, ._22(B, C), RES))
if_g_4_in_1_ggga5(A, B, C, RES, f_3_out_gga3(A, ._22(B, C), RES)) -> g_4_out_ggga4(A, B, C, RES)
if_f_3_in_1_gga5(Head, Tail, X, RES, g_4_out_ggga4(Tail, X, ._22(Head, Tail), RES)) -> f_3_out_gga3(._22(Head, Tail), X, RES)

The argument filtering Pi contains the following mapping:
f_3_in_gga3(x1, x2, x3)  =  f_3_in_gga2(x1, x2)
[]_0  =  []_0
._22(x1, x2)  =  ._22(x1, x2)
f_3_out_gga3(x1, x2, x3)  =  f_3_out_gga1(x3)
if_f_3_in_1_gga5(x1, x2, x3, x4, x5)  =  if_f_3_in_1_gga1(x5)
g_4_in_ggga4(x1, x2, x3, x4)  =  g_4_in_ggga3(x1, x2, x3)
if_g_4_in_1_ggga5(x1, x2, x3, x4, x5)  =  if_g_4_in_1_ggga1(x5)
g_4_out_ggga4(x1, x2, x3, x4)  =  g_4_out_ggga1(x4)
G_4_IN_GGGA4(x1, x2, x3, x4)  =  G_4_IN_GGGA3(x1, x2, x3)
F_3_IN_GGA3(x1, x2, x3)  =  F_3_IN_GGA2(x1, x2)

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

↳ PROLOG
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ PiDP
              ↳ UsableRulesProof
PiDP
                  ↳ PiDPToQDPProof

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

F_3_IN_GGA3(._22(Head, Tail), X, RES) -> G_4_IN_GGGA4(Tail, X, ._22(Head, Tail), RES)
G_4_IN_GGGA4(A, B, C, RES) -> F_3_IN_GGA3(A, ._22(B, C), RES)

R is empty.
The argument filtering Pi contains the following mapping:
._22(x1, x2)  =  ._22(x1, x2)
G_4_IN_GGGA4(x1, x2, x3, x4)  =  G_4_IN_GGGA3(x1, x2, x3)
F_3_IN_GGA3(x1, x2, x3)  =  F_3_IN_GGA2(x1, x2)

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

↳ PROLOG
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ PiDP
              ↳ UsableRulesProof
                ↳ PiDP
                  ↳ PiDPToQDPProof
QDP
                      ↳ QDPSizeChangeProof

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

F_3_IN_GGA2(._22(Head, Tail), X) -> G_4_IN_GGGA3(Tail, X, ._22(Head, Tail))
G_4_IN_GGGA3(A, B, C) -> F_3_IN_GGA2(A, ._22(B, C))

R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
The head symbols of this DP problem are {G_4_IN_GGGA3, F_3_IN_GGA2}.
By using the subterm criterion together with the size-change analysis 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: