(0) Obligation:

Clauses:

max(X, Y, X) :- less(Y, X).
max(X, Y, Y) :- less(X, s(Y)).
less(0, s(X1)).
less(s(X), s(Y)) :- less(X, Y).

Query: max(a,g,a)

(1) PrologToPrologProblemTransformerProof (SOUND transformation)

Built Prolog problem from termination graph ICLP10.

(2) Obligation:

Clauses:

lessA(0, s(T31)).
lessA(s(T36), s(T38)) :- lessA(T36, T38).
lessB(0, s(T68)).
lessB(s(T75), s(T74)) :- lessB(T75, T74).
maxC(s(T13), 0, s(T13)).
maxC(s(T24), s(T22), s(T24)) :- lessA(T22, T24).
maxC(0, T54, T54).
maxC(s(T61), T60, T60) :- lessB(T61, T60).
maxC(0, T87, T87).
maxC(s(T94), T93, T93) :- lessB(T94, T93).

Query: maxC(a,g,a)

(3) PrologToPiTRSProof (SOUND transformation)

We use the technique of [TOCL09]. With regard to the inferred argument filtering the predicates were used in the following modes:
maxC_in: (f,b,f)
lessA_in: (b,f)
lessB_in: (f,b)
Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)

Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog

(4) Obligation:

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

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)

(5) 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:

MAXC_IN_AGA(s(T24), s(T22), s(T24)) → U3_AGA(T24, T22, lessA_in_ga(T22, T24))
MAXC_IN_AGA(s(T24), s(T22), s(T24)) → LESSA_IN_GA(T22, T24)
LESSA_IN_GA(s(T36), s(T38)) → U1_GA(T36, T38, lessA_in_ga(T36, T38))
LESSA_IN_GA(s(T36), s(T38)) → LESSA_IN_GA(T36, T38)
MAXC_IN_AGA(s(T61), T60, T60) → U4_AGA(T61, T60, lessB_in_ag(T61, T60))
MAXC_IN_AGA(s(T61), T60, T60) → LESSB_IN_AG(T61, T60)
LESSB_IN_AG(s(T75), s(T74)) → U2_AG(T75, T74, lessB_in_ag(T75, T74))
LESSB_IN_AG(s(T75), s(T74)) → LESSB_IN_AG(T75, T74)
MAXC_IN_AGA(s(T94), T93, T93) → U5_AGA(T94, T93, lessB_in_ag(T94, T93))

The TRS R consists of the following rules:

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)
MAXC_IN_AGA(x1, x2, x3)  =  MAXC_IN_AGA(x2)
U3_AGA(x1, x2, x3)  =  U3_AGA(x3)
LESSA_IN_GA(x1, x2)  =  LESSA_IN_GA(x1)
U1_GA(x1, x2, x3)  =  U1_GA(x3)
U4_AGA(x1, x2, x3)  =  U4_AGA(x3)
LESSB_IN_AG(x1, x2)  =  LESSB_IN_AG(x2)
U2_AG(x1, x2, x3)  =  U2_AG(x3)
U5_AGA(x1, x2, x3)  =  U5_AGA(x3)

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

(6) Obligation:

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

MAXC_IN_AGA(s(T24), s(T22), s(T24)) → U3_AGA(T24, T22, lessA_in_ga(T22, T24))
MAXC_IN_AGA(s(T24), s(T22), s(T24)) → LESSA_IN_GA(T22, T24)
LESSA_IN_GA(s(T36), s(T38)) → U1_GA(T36, T38, lessA_in_ga(T36, T38))
LESSA_IN_GA(s(T36), s(T38)) → LESSA_IN_GA(T36, T38)
MAXC_IN_AGA(s(T61), T60, T60) → U4_AGA(T61, T60, lessB_in_ag(T61, T60))
MAXC_IN_AGA(s(T61), T60, T60) → LESSB_IN_AG(T61, T60)
LESSB_IN_AG(s(T75), s(T74)) → U2_AG(T75, T74, lessB_in_ag(T75, T74))
LESSB_IN_AG(s(T75), s(T74)) → LESSB_IN_AG(T75, T74)
MAXC_IN_AGA(s(T94), T93, T93) → U5_AGA(T94, T93, lessB_in_ag(T94, T93))

The TRS R consists of the following rules:

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)
MAXC_IN_AGA(x1, x2, x3)  =  MAXC_IN_AGA(x2)
U3_AGA(x1, x2, x3)  =  U3_AGA(x3)
LESSA_IN_GA(x1, x2)  =  LESSA_IN_GA(x1)
U1_GA(x1, x2, x3)  =  U1_GA(x3)
U4_AGA(x1, x2, x3)  =  U4_AGA(x3)
LESSB_IN_AG(x1, x2)  =  LESSB_IN_AG(x2)
U2_AG(x1, x2, x3)  =  U2_AG(x3)
U5_AGA(x1, x2, x3)  =  U5_AGA(x3)

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

(7) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LOPSTR] contains 2 SCCs with 7 less nodes.

(8) Complex Obligation (AND)

(9) Obligation:

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

LESSB_IN_AG(s(T75), s(T74)) → LESSB_IN_AG(T75, T74)

The TRS R consists of the following rules:

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)
LESSB_IN_AG(x1, x2)  =  LESSB_IN_AG(x2)

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

(10) UsableRulesProof (EQUIVALENT transformation)

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

(11) Obligation:

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

LESSB_IN_AG(s(T75), s(T74)) → LESSB_IN_AG(T75, T74)

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

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

(12) PiDPToQDPProof (SOUND transformation)

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

(13) Obligation:

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

LESSB_IN_AG(s(T74)) → LESSB_IN_AG(T74)

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

(14) 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:

  • LESSB_IN_AG(s(T74)) → LESSB_IN_AG(T74)
    The graph contains the following edges 1 > 1

(15) YES

(16) Obligation:

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

LESSA_IN_GA(s(T36), s(T38)) → LESSA_IN_GA(T36, T38)

The TRS R consists of the following rules:

maxC_in_aga(s(T13), 0, s(T13)) → maxC_out_aga(s(T13), 0, s(T13))
maxC_in_aga(s(T24), s(T22), s(T24)) → U3_aga(T24, T22, lessA_in_ga(T22, T24))
lessA_in_ga(0, s(T31)) → lessA_out_ga(0, s(T31))
lessA_in_ga(s(T36), s(T38)) → U1_ga(T36, T38, lessA_in_ga(T36, T38))
U1_ga(T36, T38, lessA_out_ga(T36, T38)) → lessA_out_ga(s(T36), s(T38))
U3_aga(T24, T22, lessA_out_ga(T22, T24)) → maxC_out_aga(s(T24), s(T22), s(T24))
maxC_in_aga(0, T54, T54) → maxC_out_aga(0, T54, T54)
maxC_in_aga(s(T61), T60, T60) → U4_aga(T61, T60, lessB_in_ag(T61, T60))
lessB_in_ag(0, s(T68)) → lessB_out_ag(0, s(T68))
lessB_in_ag(s(T75), s(T74)) → U2_ag(T75, T74, lessB_in_ag(T75, T74))
U2_ag(T75, T74, lessB_out_ag(T75, T74)) → lessB_out_ag(s(T75), s(T74))
U4_aga(T61, T60, lessB_out_ag(T61, T60)) → maxC_out_aga(s(T61), T60, T60)
maxC_in_aga(s(T94), T93, T93) → U5_aga(T94, T93, lessB_in_ag(T94, T93))
U5_aga(T94, T93, lessB_out_ag(T94, T93)) → maxC_out_aga(s(T94), T93, T93)

The argument filtering Pi contains the following mapping:
maxC_in_aga(x1, x2, x3)  =  maxC_in_aga(x2)
0  =  0
maxC_out_aga(x1, x2, x3)  =  maxC_out_aga
s(x1)  =  s(x1)
U3_aga(x1, x2, x3)  =  U3_aga(x3)
lessA_in_ga(x1, x2)  =  lessA_in_ga(x1)
lessA_out_ga(x1, x2)  =  lessA_out_ga
U1_ga(x1, x2, x3)  =  U1_ga(x3)
U4_aga(x1, x2, x3)  =  U4_aga(x3)
lessB_in_ag(x1, x2)  =  lessB_in_ag(x2)
lessB_out_ag(x1, x2)  =  lessB_out_ag(x1)
U2_ag(x1, x2, x3)  =  U2_ag(x3)
U5_aga(x1, x2, x3)  =  U5_aga(x3)
LESSA_IN_GA(x1, x2)  =  LESSA_IN_GA(x1)

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

(17) UsableRulesProof (EQUIVALENT transformation)

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

(18) Obligation:

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

LESSA_IN_GA(s(T36), s(T38)) → LESSA_IN_GA(T36, T38)

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

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

(19) PiDPToQDPProof (SOUND transformation)

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

(20) Obligation:

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

LESSA_IN_GA(s(T36)) → LESSA_IN_GA(T36)

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

(21) 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:

  • LESSA_IN_GA(s(T36)) → LESSA_IN_GA(T36)
    The graph contains the following edges 1 > 1

(22) YES