YES
proof of /hpcwork/ff862203/termcomp26/benchmarks/TgxL0.pl
# AProVE Commit ID: 23a904c96b029b0a549cde0d0d17dbccf967db59 jckassing 20260626 unpublished dirty


Left Termination of the query pattern

reverse(g,g,a)

w.r.t. the given Prolog program could successfully be proven:

(0) Prolog
(1) PrologToPiTRSProof [SOUND, 0 ms]
(2) PiTRS
(3) DependencyPairsProof [EQUIVALENT, 0 ms]
(4) PiDP
(5) DependencyGraphProof [EQUIVALENT, 0 ms]
(6) PiDP
(7) UsableRulesProof [EQUIVALENT, 0 ms]
(8) PiDP
(9) PiDPToQDPProof [SOUND, 0 ms]
(10) QDP
(11) QDPSizeChangeProof [EQUIVALENT, 0 ms]
(12) YES


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(0)
Obligation:
Clauses:

reverse([], X, X).
reverse(.(X, Y), Z, U) :- reverse(Y, Z, .(X, U)).


Query: reverse(g,g,a)
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(1) PrologToPiTRSProof (SOUND)
We use the technique of [TOCL09]. With regard to the inferred argument filtering the predicates were used in the following modes:

reverse_in_3: (b,b,f)

Transforming Prolog into the following Term Rewriting System:

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

   reverse_in_gga([], X, X) -> reverse_out_gga([], X, X)
   reverse_in_gga(.(X, Y), Z, U) -> U1_gga(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   U1_gga(X, Y, Z, U, reverse_out_gga(Y, Z, .(X, U))) -> reverse_out_gga(.(X, Y), Z, U)

The argument filtering Pi contains the following mapping:
reverse_in_gga(x1, x2, x3)  =  reverse_in_gga(x1, x2)

[]  =  []

reverse_out_gga(x1, x2, x3)  =  reverse_out_gga(x3)

.(x1, x2)  =  .(x1, x2)

U1_gga(x1, x2, x3, x4, x5)  =  U1_gga(x5)





Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog



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(2)
Obligation:
Pi-finite rewrite system:
The TRS R consists of the following rules:

   reverse_in_gga([], X, X) -> reverse_out_gga([], X, X)
   reverse_in_gga(.(X, Y), Z, U) -> U1_gga(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   U1_gga(X, Y, Z, U, reverse_out_gga(Y, Z, .(X, U))) -> reverse_out_gga(.(X, Y), Z, U)

The argument filtering Pi contains the following mapping:
reverse_in_gga(x1, x2, x3)  =  reverse_in_gga(x1, x2)

[]  =  []

reverse_out_gga(x1, x2, x3)  =  reverse_out_gga(x3)

.(x1, x2)  =  .(x1, x2)

U1_gga(x1, x2, x3, x4, x5)  =  U1_gga(x5)



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(3) DependencyPairsProof (EQUIVALENT)
Using Dependency Pairs [AG00,LOPSTR] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:

   REVERSE_IN_GGA(.(X, Y), Z, U) -> U1_GGA(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   REVERSE_IN_GGA(.(X, Y), Z, U) -> REVERSE_IN_GGA(Y, Z, .(X, U))

The TRS R consists of the following rules:

   reverse_in_gga([], X, X) -> reverse_out_gga([], X, X)
   reverse_in_gga(.(X, Y), Z, U) -> U1_gga(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   U1_gga(X, Y, Z, U, reverse_out_gga(Y, Z, .(X, U))) -> reverse_out_gga(.(X, Y), Z, U)

The argument filtering Pi contains the following mapping:
reverse_in_gga(x1, x2, x3)  =  reverse_in_gga(x1, x2)

[]  =  []

reverse_out_gga(x1, x2, x3)  =  reverse_out_gga(x3)

.(x1, x2)  =  .(x1, x2)

U1_gga(x1, x2, x3, x4, x5)  =  U1_gga(x5)

REVERSE_IN_GGA(x1, x2, x3)  =  REVERSE_IN_GGA(x1, x2)

U1_GGA(x1, x2, x3, x4, x5)  =  U1_GGA(x5)


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

(4)
Obligation:
Pi DP problem:
The TRS P consists of the following rules:

   REVERSE_IN_GGA(.(X, Y), Z, U) -> U1_GGA(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   REVERSE_IN_GGA(.(X, Y), Z, U) -> REVERSE_IN_GGA(Y, Z, .(X, U))

The TRS R consists of the following rules:

   reverse_in_gga([], X, X) -> reverse_out_gga([], X, X)
   reverse_in_gga(.(X, Y), Z, U) -> U1_gga(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   U1_gga(X, Y, Z, U, reverse_out_gga(Y, Z, .(X, U))) -> reverse_out_gga(.(X, Y), Z, U)

The argument filtering Pi contains the following mapping:
reverse_in_gga(x1, x2, x3)  =  reverse_in_gga(x1, x2)

[]  =  []

reverse_out_gga(x1, x2, x3)  =  reverse_out_gga(x3)

.(x1, x2)  =  .(x1, x2)

U1_gga(x1, x2, x3, x4, x5)  =  U1_gga(x5)

REVERSE_IN_GGA(x1, x2, x3)  =  REVERSE_IN_GGA(x1, x2)

U1_GGA(x1, x2, x3, x4, x5)  =  U1_GGA(x5)


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

(5) DependencyGraphProof (EQUIVALENT)
The approximation of the Dependency Graph [LOPSTR] contains 1 SCC with 1 less node.
----------------------------------------

(6)
Obligation:
Pi DP problem:
The TRS P consists of the following rules:

   REVERSE_IN_GGA(.(X, Y), Z, U) -> REVERSE_IN_GGA(Y, Z, .(X, U))

The TRS R consists of the following rules:

   reverse_in_gga([], X, X) -> reverse_out_gga([], X, X)
   reverse_in_gga(.(X, Y), Z, U) -> U1_gga(X, Y, Z, U, reverse_in_gga(Y, Z, .(X, U)))
   U1_gga(X, Y, Z, U, reverse_out_gga(Y, Z, .(X, U))) -> reverse_out_gga(.(X, Y), Z, U)

The argument filtering Pi contains the following mapping:
reverse_in_gga(x1, x2, x3)  =  reverse_in_gga(x1, x2)

[]  =  []

reverse_out_gga(x1, x2, x3)  =  reverse_out_gga(x3)

.(x1, x2)  =  .(x1, x2)

U1_gga(x1, x2, x3, x4, x5)  =  U1_gga(x5)

REVERSE_IN_GGA(x1, x2, x3)  =  REVERSE_IN_GGA(x1, x2)


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

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

(8)
Obligation:
Pi DP problem:
The TRS P consists of the following rules:

   REVERSE_IN_GGA(.(X, Y), Z, U) -> REVERSE_IN_GGA(Y, Z, .(X, U))

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

REVERSE_IN_GGA(x1, x2, x3)  =  REVERSE_IN_GGA(x1, x2)


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

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

(10)
Obligation:
Q DP problem:
The TRS P consists of the following rules:

   REVERSE_IN_GGA(.(X, Y), Z) -> REVERSE_IN_GGA(Y, Z)

R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
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(11) QDPSizeChangeProof (EQUIVALENT)
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:
*REVERSE_IN_GGA(.(X, Y), Z) -> REVERSE_IN_GGA(Y, Z)
The graph contains the following edges 1 > 1, 2 >= 2


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(12)
YES
