Left Termination of the query pattern factorial_in_2(g, a) w.r.t. the given Prolog program could successfully be proven:



Prolog
  ↳ PrologToPiTRSProof

Clauses:

isNat(s(X)) :- isNat(X).
isNat(0).
notEq(s(X), s(Y)) :- notEq(X, Y).
notEq(s(X), 0).
notEq(0, s(X)).
lt(s(X), s(Y)) :- lt(X, Y).
lt(0, s(Y)).
gt(s(X), s(Y)) :- gt(X, Y).
gt(s(X), 0).
le(s(X), s(Y)) :- le(X, Y).
le(0, s(Y)).
le(0, 0).
even(s(X)) :- odd(X).
even(0).
odd(s(X)) :- even(X).
odd(s(0)).
add(s(X), Y, s(Z)) :- add(X, Y, Z).
add(0, X, X).
mult(s(X), Y, R) :- ','(mult(X, Y, Z), add(Y, Z, R)).
mult(0, Y, 0).
factorial(s(X), R) :- ','(factorial(X, Y), mult(s(X), Y, R)).
factorial(0, s(0)).

Queries:

factorial(g,a).

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

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)

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:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)


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

FACTORIAL_IN_GA(s(X), R) → U11_GA(X, R, factorial_in_ga(X, Y))
FACTORIAL_IN_GA(s(X), R) → FACTORIAL_IN_GA(X, Y)
U11_GA(X, R, factorial_out_ga(X, Y)) → U12_GA(X, R, mult_in_gga(s(X), Y, R))
U11_GA(X, R, factorial_out_ga(X, Y)) → MULT_IN_GGA(s(X), Y, R)
MULT_IN_GGA(s(X), Y, R) → U9_GGA(X, Y, R, mult_in_gga(X, Y, Z))
MULT_IN_GGA(s(X), Y, R) → MULT_IN_GGA(X, Y, Z)
U9_GGA(X, Y, R, mult_out_gga(X, Y, Z)) → U10_GGA(X, Y, R, add_in_gga(Y, Z, R))
U9_GGA(X, Y, R, mult_out_gga(X, Y, Z)) → ADD_IN_GGA(Y, Z, R)
ADD_IN_GGA(s(X), Y, s(Z)) → U8_GGA(X, Y, Z, add_in_gga(X, Y, Z))
ADD_IN_GGA(s(X), Y, s(Z)) → ADD_IN_GGA(X, Y, Z)

The TRS R consists of the following rules:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)
ADD_IN_GGA(x1, x2, x3)  =  ADD_IN_GGA(x1, x2)
U10_GGA(x1, x2, x3, x4)  =  U10_GGA(x4)
U12_GA(x1, x2, x3)  =  U12_GA(x3)
U11_GA(x1, x2, x3)  =  U11_GA(x1, x3)
U9_GGA(x1, x2, x3, x4)  =  U9_GGA(x2, x4)
MULT_IN_GGA(x1, x2, x3)  =  MULT_IN_GGA(x1, x2)
U8_GGA(x1, x2, x3, x4)  =  U8_GGA(x4)
FACTORIAL_IN_GA(x1, x2)  =  FACTORIAL_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:

FACTORIAL_IN_GA(s(X), R) → U11_GA(X, R, factorial_in_ga(X, Y))
FACTORIAL_IN_GA(s(X), R) → FACTORIAL_IN_GA(X, Y)
U11_GA(X, R, factorial_out_ga(X, Y)) → U12_GA(X, R, mult_in_gga(s(X), Y, R))
U11_GA(X, R, factorial_out_ga(X, Y)) → MULT_IN_GGA(s(X), Y, R)
MULT_IN_GGA(s(X), Y, R) → U9_GGA(X, Y, R, mult_in_gga(X, Y, Z))
MULT_IN_GGA(s(X), Y, R) → MULT_IN_GGA(X, Y, Z)
U9_GGA(X, Y, R, mult_out_gga(X, Y, Z)) → U10_GGA(X, Y, R, add_in_gga(Y, Z, R))
U9_GGA(X, Y, R, mult_out_gga(X, Y, Z)) → ADD_IN_GGA(Y, Z, R)
ADD_IN_GGA(s(X), Y, s(Z)) → U8_GGA(X, Y, Z, add_in_gga(X, Y, Z))
ADD_IN_GGA(s(X), Y, s(Z)) → ADD_IN_GGA(X, Y, Z)

The TRS R consists of the following rules:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)
ADD_IN_GGA(x1, x2, x3)  =  ADD_IN_GGA(x1, x2)
U10_GGA(x1, x2, x3, x4)  =  U10_GGA(x4)
U12_GA(x1, x2, x3)  =  U12_GA(x3)
U11_GA(x1, x2, x3)  =  U11_GA(x1, x3)
U9_GGA(x1, x2, x3, x4)  =  U9_GGA(x2, x4)
MULT_IN_GGA(x1, x2, x3)  =  MULT_IN_GGA(x1, x2)
U8_GGA(x1, x2, x3, x4)  =  U8_GGA(x4)
FACTORIAL_IN_GA(x1, x2)  =  FACTORIAL_IN_GA(x1)

We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 3 SCCs with 7 less nodes.

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

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

ADD_IN_GGA(s(X), Y, s(Z)) → ADD_IN_GGA(X, Y, Z)

The TRS R consists of the following rules:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)
ADD_IN_GGA(x1, x2, x3)  =  ADD_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:

ADD_IN_GGA(s(X), Y, s(Z)) → ADD_IN_GGA(X, Y, Z)

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

ADD_IN_GGA(s(X), Y) → ADD_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:

MULT_IN_GGA(s(X), Y, R) → MULT_IN_GGA(X, Y, Z)

The TRS R consists of the following rules:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)
MULT_IN_GGA(x1, x2, x3)  =  MULT_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
              ↳ PiDP
                ↳ UsableRulesProof
PiDP
                    ↳ PiDPToQDPProof
              ↳ PiDP

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

MULT_IN_GGA(s(X), Y, R) → MULT_IN_GGA(X, Y, Z)

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

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

MULT_IN_GGA(s(X), Y) → MULT_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
PiDP
                ↳ UsableRulesProof

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

FACTORIAL_IN_GA(s(X), R) → FACTORIAL_IN_GA(X, Y)

The TRS R consists of the following rules:

factorial_in_ga(s(X), R) → U11_ga(X, R, factorial_in_ga(X, Y))
factorial_in_ga(0, s(0)) → factorial_out_ga(0, s(0))
U11_ga(X, R, factorial_out_ga(X, Y)) → U12_ga(X, R, mult_in_gga(s(X), Y, R))
mult_in_gga(s(X), Y, R) → U9_gga(X, Y, R, mult_in_gga(X, Y, Z))
mult_in_gga(0, Y, 0) → mult_out_gga(0, Y, 0)
U9_gga(X, Y, R, mult_out_gga(X, Y, Z)) → U10_gga(X, Y, R, add_in_gga(Y, Z, R))
add_in_gga(s(X), Y, s(Z)) → U8_gga(X, Y, Z, add_in_gga(X, Y, Z))
add_in_gga(0, X, X) → add_out_gga(0, X, X)
U8_gga(X, Y, Z, add_out_gga(X, Y, Z)) → add_out_gga(s(X), Y, s(Z))
U10_gga(X, Y, R, add_out_gga(Y, Z, R)) → mult_out_gga(s(X), Y, R)
U12_ga(X, R, mult_out_gga(s(X), Y, R)) → factorial_out_ga(s(X), R)

The argument filtering Pi contains the following mapping:
factorial_in_ga(x1, x2)  =  factorial_in_ga(x1)
s(x1)  =  s(x1)
U11_ga(x1, x2, x3)  =  U11_ga(x1, x3)
0  =  0
factorial_out_ga(x1, x2)  =  factorial_out_ga(x2)
U12_ga(x1, x2, x3)  =  U12_ga(x3)
mult_in_gga(x1, x2, x3)  =  mult_in_gga(x1, x2)
U9_gga(x1, x2, x3, x4)  =  U9_gga(x2, x4)
mult_out_gga(x1, x2, x3)  =  mult_out_gga(x3)
U10_gga(x1, x2, x3, x4)  =  U10_gga(x4)
add_in_gga(x1, x2, x3)  =  add_in_gga(x1, x2)
U8_gga(x1, x2, x3, x4)  =  U8_gga(x4)
add_out_gga(x1, x2, x3)  =  add_out_gga(x3)
FACTORIAL_IN_GA(x1, x2)  =  FACTORIAL_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:

FACTORIAL_IN_GA(s(X), R) → FACTORIAL_IN_GA(X, Y)

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

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

FACTORIAL_IN_GA(s(X)) → FACTORIAL_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: