(0) Obligation:

Clauses:

select(X, Y, Zs) :- ','(no(empty(Y)), ','(head(Y, X), tail(Y, Zs))).
select(X, Y, Z) :- ','(no(empty(Y)), ','(head(Y, H), ','(head(Z, H), ','(tail(Y, T), ','(tail(Z, Zs), select(X, T, Zs)))))).
head([], X1).
head(.(H, X2), H).
tail([], []).
tail(.(X3, T), T).
empty([]).
no(X) :- ','(X, ','(!, failure(a))).
no(X4).
failure(b).

Query: select(g,g,a)

(1) PrologToPiTRSViaGraphTransformerProof (SOUND transformation)

Transformed Prolog program to (Pi-)TRS.

(2) Obligation:

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

selectA_in_gga(T41, .(T41, T42), T42) → selectA_out_gga(T41, .(T41, T42), T42)
selectA_in_gga(T51, .(T83, T84), []) → U1_gga(T51, T83, T84, selectB_in_gg(T51, T84))
selectB_in_gg(T120, .(T120, [])) → selectB_out_gg(T120, .(T120, []))
selectB_in_gg(T127, .(T160, T161)) → U3_gg(T127, T160, T161, selectB_in_gg(T127, T161))
U3_gg(T127, T160, T161, selectB_out_gg(T127, T161)) → selectB_out_gg(T127, .(T160, T161))
U1_gga(T51, T83, T84, selectB_out_gg(T51, T84)) → selectA_out_gga(T51, .(T83, T84), [])
selectA_in_gga(T51, .(T196, T185), .(T196, T198)) → U2_gga(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
U2_gga(T51, T196, T185, T198, selectA_out_gga(T51, T185, T198)) → selectA_out_gga(T51, .(T196, T185), .(T196, T198))

The argument filtering Pi contains the following mapping:
selectA_in_gga(x1, x2, x3)  =  selectA_in_gga(x1, x2)
.(x1, x2)  =  .(x1, x2)
selectA_out_gga(x1, x2, x3)  =  selectA_out_gga(x1, x2, x3)
U1_gga(x1, x2, x3, x4)  =  U1_gga(x1, x2, x3, x4)
selectB_in_gg(x1, x2)  =  selectB_in_gg(x1, x2)
[]  =  []
selectB_out_gg(x1, x2)  =  selectB_out_gg(x1, x2)
U3_gg(x1, x2, x3, x4)  =  U3_gg(x1, x2, x3, x4)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x1, x2, x3, x5)

(3) 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:

SELECTA_IN_GGA(T51, .(T83, T84), []) → U1_GGA(T51, T83, T84, selectB_in_gg(T51, T84))
SELECTA_IN_GGA(T51, .(T83, T84), []) → SELECTB_IN_GG(T51, T84)
SELECTB_IN_GG(T127, .(T160, T161)) → U3_GG(T127, T160, T161, selectB_in_gg(T127, T161))
SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)
SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → U2_GGA(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → SELECTA_IN_GGA(T51, T185, T198)

The TRS R consists of the following rules:

selectA_in_gga(T41, .(T41, T42), T42) → selectA_out_gga(T41, .(T41, T42), T42)
selectA_in_gga(T51, .(T83, T84), []) → U1_gga(T51, T83, T84, selectB_in_gg(T51, T84))
selectB_in_gg(T120, .(T120, [])) → selectB_out_gg(T120, .(T120, []))
selectB_in_gg(T127, .(T160, T161)) → U3_gg(T127, T160, T161, selectB_in_gg(T127, T161))
U3_gg(T127, T160, T161, selectB_out_gg(T127, T161)) → selectB_out_gg(T127, .(T160, T161))
U1_gga(T51, T83, T84, selectB_out_gg(T51, T84)) → selectA_out_gga(T51, .(T83, T84), [])
selectA_in_gga(T51, .(T196, T185), .(T196, T198)) → U2_gga(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
U2_gga(T51, T196, T185, T198, selectA_out_gga(T51, T185, T198)) → selectA_out_gga(T51, .(T196, T185), .(T196, T198))

The argument filtering Pi contains the following mapping:
selectA_in_gga(x1, x2, x3)  =  selectA_in_gga(x1, x2)
.(x1, x2)  =  .(x1, x2)
selectA_out_gga(x1, x2, x3)  =  selectA_out_gga(x1, x2, x3)
U1_gga(x1, x2, x3, x4)  =  U1_gga(x1, x2, x3, x4)
selectB_in_gg(x1, x2)  =  selectB_in_gg(x1, x2)
[]  =  []
selectB_out_gg(x1, x2)  =  selectB_out_gg(x1, x2)
U3_gg(x1, x2, x3, x4)  =  U3_gg(x1, x2, x3, x4)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x1, x2, x3, x5)
SELECTA_IN_GGA(x1, x2, x3)  =  SELECTA_IN_GGA(x1, x2)
U1_GGA(x1, x2, x3, x4)  =  U1_GGA(x1, x2, x3, x4)
SELECTB_IN_GG(x1, x2)  =  SELECTB_IN_GG(x1, x2)
U3_GG(x1, x2, x3, x4)  =  U3_GG(x1, x2, x3, x4)
U2_GGA(x1, x2, x3, x4, x5)  =  U2_GGA(x1, x2, x3, x5)

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

(4) Obligation:

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

SELECTA_IN_GGA(T51, .(T83, T84), []) → U1_GGA(T51, T83, T84, selectB_in_gg(T51, T84))
SELECTA_IN_GGA(T51, .(T83, T84), []) → SELECTB_IN_GG(T51, T84)
SELECTB_IN_GG(T127, .(T160, T161)) → U3_GG(T127, T160, T161, selectB_in_gg(T127, T161))
SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)
SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → U2_GGA(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → SELECTA_IN_GGA(T51, T185, T198)

The TRS R consists of the following rules:

selectA_in_gga(T41, .(T41, T42), T42) → selectA_out_gga(T41, .(T41, T42), T42)
selectA_in_gga(T51, .(T83, T84), []) → U1_gga(T51, T83, T84, selectB_in_gg(T51, T84))
selectB_in_gg(T120, .(T120, [])) → selectB_out_gg(T120, .(T120, []))
selectB_in_gg(T127, .(T160, T161)) → U3_gg(T127, T160, T161, selectB_in_gg(T127, T161))
U3_gg(T127, T160, T161, selectB_out_gg(T127, T161)) → selectB_out_gg(T127, .(T160, T161))
U1_gga(T51, T83, T84, selectB_out_gg(T51, T84)) → selectA_out_gga(T51, .(T83, T84), [])
selectA_in_gga(T51, .(T196, T185), .(T196, T198)) → U2_gga(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
U2_gga(T51, T196, T185, T198, selectA_out_gga(T51, T185, T198)) → selectA_out_gga(T51, .(T196, T185), .(T196, T198))

The argument filtering Pi contains the following mapping:
selectA_in_gga(x1, x2, x3)  =  selectA_in_gga(x1, x2)
.(x1, x2)  =  .(x1, x2)
selectA_out_gga(x1, x2, x3)  =  selectA_out_gga(x1, x2, x3)
U1_gga(x1, x2, x3, x4)  =  U1_gga(x1, x2, x3, x4)
selectB_in_gg(x1, x2)  =  selectB_in_gg(x1, x2)
[]  =  []
selectB_out_gg(x1, x2)  =  selectB_out_gg(x1, x2)
U3_gg(x1, x2, x3, x4)  =  U3_gg(x1, x2, x3, x4)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x1, x2, x3, x5)
SELECTA_IN_GGA(x1, x2, x3)  =  SELECTA_IN_GGA(x1, x2)
U1_GGA(x1, x2, x3, x4)  =  U1_GGA(x1, x2, x3, x4)
SELECTB_IN_GG(x1, x2)  =  SELECTB_IN_GG(x1, x2)
U3_GG(x1, x2, x3, x4)  =  U3_GG(x1, x2, x3, x4)
U2_GGA(x1, x2, x3, x4, x5)  =  U2_GGA(x1, x2, x3, x5)

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

(5) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LOPSTR] contains 2 SCCs with 4 less nodes.

(6) Complex Obligation (AND)

(7) Obligation:

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

SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)

The TRS R consists of the following rules:

selectA_in_gga(T41, .(T41, T42), T42) → selectA_out_gga(T41, .(T41, T42), T42)
selectA_in_gga(T51, .(T83, T84), []) → U1_gga(T51, T83, T84, selectB_in_gg(T51, T84))
selectB_in_gg(T120, .(T120, [])) → selectB_out_gg(T120, .(T120, []))
selectB_in_gg(T127, .(T160, T161)) → U3_gg(T127, T160, T161, selectB_in_gg(T127, T161))
U3_gg(T127, T160, T161, selectB_out_gg(T127, T161)) → selectB_out_gg(T127, .(T160, T161))
U1_gga(T51, T83, T84, selectB_out_gg(T51, T84)) → selectA_out_gga(T51, .(T83, T84), [])
selectA_in_gga(T51, .(T196, T185), .(T196, T198)) → U2_gga(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
U2_gga(T51, T196, T185, T198, selectA_out_gga(T51, T185, T198)) → selectA_out_gga(T51, .(T196, T185), .(T196, T198))

The argument filtering Pi contains the following mapping:
selectA_in_gga(x1, x2, x3)  =  selectA_in_gga(x1, x2)
.(x1, x2)  =  .(x1, x2)
selectA_out_gga(x1, x2, x3)  =  selectA_out_gga(x1, x2, x3)
U1_gga(x1, x2, x3, x4)  =  U1_gga(x1, x2, x3, x4)
selectB_in_gg(x1, x2)  =  selectB_in_gg(x1, x2)
[]  =  []
selectB_out_gg(x1, x2)  =  selectB_out_gg(x1, x2)
U3_gg(x1, x2, x3, x4)  =  U3_gg(x1, x2, x3, x4)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x1, x2, x3, x5)
SELECTB_IN_GG(x1, x2)  =  SELECTB_IN_GG(x1, x2)

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

(8) UsableRulesProof (EQUIVALENT transformation)

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

(9) Obligation:

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

SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)

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

(10) PiDPToQDPProof (EQUIVALENT transformation)

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

(11) Obligation:

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

SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)

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

(12) 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:

  • SELECTB_IN_GG(T127, .(T160, T161)) → SELECTB_IN_GG(T127, T161)
    The graph contains the following edges 1 >= 1, 2 > 2

(13) YES

(14) Obligation:

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

SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → SELECTA_IN_GGA(T51, T185, T198)

The TRS R consists of the following rules:

selectA_in_gga(T41, .(T41, T42), T42) → selectA_out_gga(T41, .(T41, T42), T42)
selectA_in_gga(T51, .(T83, T84), []) → U1_gga(T51, T83, T84, selectB_in_gg(T51, T84))
selectB_in_gg(T120, .(T120, [])) → selectB_out_gg(T120, .(T120, []))
selectB_in_gg(T127, .(T160, T161)) → U3_gg(T127, T160, T161, selectB_in_gg(T127, T161))
U3_gg(T127, T160, T161, selectB_out_gg(T127, T161)) → selectB_out_gg(T127, .(T160, T161))
U1_gga(T51, T83, T84, selectB_out_gg(T51, T84)) → selectA_out_gga(T51, .(T83, T84), [])
selectA_in_gga(T51, .(T196, T185), .(T196, T198)) → U2_gga(T51, T196, T185, T198, selectA_in_gga(T51, T185, T198))
U2_gga(T51, T196, T185, T198, selectA_out_gga(T51, T185, T198)) → selectA_out_gga(T51, .(T196, T185), .(T196, T198))

The argument filtering Pi contains the following mapping:
selectA_in_gga(x1, x2, x3)  =  selectA_in_gga(x1, x2)
.(x1, x2)  =  .(x1, x2)
selectA_out_gga(x1, x2, x3)  =  selectA_out_gga(x1, x2, x3)
U1_gga(x1, x2, x3, x4)  =  U1_gga(x1, x2, x3, x4)
selectB_in_gg(x1, x2)  =  selectB_in_gg(x1, x2)
[]  =  []
selectB_out_gg(x1, x2)  =  selectB_out_gg(x1, x2)
U3_gg(x1, x2, x3, x4)  =  U3_gg(x1, x2, x3, x4)
U2_gga(x1, x2, x3, x4, x5)  =  U2_gga(x1, x2, x3, x5)
SELECTA_IN_GGA(x1, x2, x3)  =  SELECTA_IN_GGA(x1, x2)

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

(15) UsableRulesProof (EQUIVALENT transformation)

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

(16) Obligation:

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

SELECTA_IN_GGA(T51, .(T196, T185), .(T196, T198)) → SELECTA_IN_GGA(T51, T185, T198)

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

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

(17) PiDPToQDPProof (SOUND transformation)

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

(18) Obligation:

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

SELECTA_IN_GGA(T51, .(T196, T185)) → SELECTA_IN_GGA(T51, T185)

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

(19) 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:

  • SELECTA_IN_GGA(T51, .(T196, T185)) → SELECTA_IN_GGA(T51, T185)
    The graph contains the following edges 1 >= 1, 2 > 2

(20) YES