(0) Obligation:
Clauses:
less(0, Y) :- ','(!, =(Y, s(X2))).
less(X, Y) :- ','(p(X, X1), ','(p(Y, Y1), less(X1, Y1))).
p(0, 0).
p(s(X), X).
=(X, X).
Queries:
less(g,a).
(1) PrologToPrologProblemTransformerProof (SOUND transformation)
Built Prolog problem from termination graph.
(2) Obligation:
Clauses:
less18(s(T12)) :- less18(T12).
less1(0, s(T6)).
less1(s(s(T12)), 0) :- less18(T12).
less1(s(T10), s(T14)) :- less1(T10, T14).
less1(s(T10), s(T16)) :- less1(T10, T16).
Queries:
less1(g,a).
(3) PrologToPiTRSProof (SOUND transformation)
We use the technique of [LOPSTR]. With regard to the inferred argument filtering the predicates were used in the following modes:
less1_in: (b,f)
less18_in: (b)
Transforming
Prolog into the following
Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
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:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
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:
LESS1_IN_GA(s(s(T12)), 0) → U2_GA(T12, less18_in_g(T12))
LESS1_IN_GA(s(s(T12)), 0) → LESS18_IN_G(T12)
LESS18_IN_G(s(T12)) → U1_G(T12, less18_in_g(T12))
LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
LESS1_IN_GA(s(T10), s(T14)) → U3_GA(T10, T14, less1_in_ga(T10, T14))
LESS1_IN_GA(s(T10), s(T14)) → LESS1_IN_GA(T10, T14)
LESS1_IN_GA(s(T10), s(T16)) → U4_GA(T10, T16, less1_in_ga(T10, T16))
The TRS R consists of the following rules:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
x3)
LESS1_IN_GA(
x1,
x2) =
LESS1_IN_GA(
x1)
U2_GA(
x1,
x2) =
U2_GA(
x2)
LESS18_IN_G(
x1) =
LESS18_IN_G(
x1)
U1_G(
x1,
x2) =
U1_G(
x2)
U3_GA(
x1,
x2,
x3) =
U3_GA(
x3)
U4_GA(
x1,
x2,
x3) =
U4_GA(
x3)
We have to consider all (P,R,Pi)-chains
(6) Obligation:
Pi DP problem:
The TRS P consists of the following rules:
LESS1_IN_GA(s(s(T12)), 0) → U2_GA(T12, less18_in_g(T12))
LESS1_IN_GA(s(s(T12)), 0) → LESS18_IN_G(T12)
LESS18_IN_G(s(T12)) → U1_G(T12, less18_in_g(T12))
LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
LESS1_IN_GA(s(T10), s(T14)) → U3_GA(T10, T14, less1_in_ga(T10, T14))
LESS1_IN_GA(s(T10), s(T14)) → LESS1_IN_GA(T10, T14)
LESS1_IN_GA(s(T10), s(T16)) → U4_GA(T10, T16, less1_in_ga(T10, T16))
The TRS R consists of the following rules:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
x3)
LESS1_IN_GA(
x1,
x2) =
LESS1_IN_GA(
x1)
U2_GA(
x1,
x2) =
U2_GA(
x2)
LESS18_IN_G(
x1) =
LESS18_IN_G(
x1)
U1_G(
x1,
x2) =
U1_G(
x2)
U3_GA(
x1,
x2,
x3) =
U3_GA(
x3)
U4_GA(
x1,
x2,
x3) =
U4_GA(
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 5 less nodes.
(8) Complex Obligation (AND)
(9) Obligation:
Pi DP problem:
The TRS P consists of the following rules:
LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
The TRS R consists of the following rules:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
x3)
LESS18_IN_G(
x1) =
LESS18_IN_G(
x1)
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:
LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
R is empty.
Pi is empty.
We have to consider all (P,R,Pi)-chains
(12) PiDPToQDPProof (EQUIVALENT 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:
LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
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:
- LESS18_IN_G(s(T12)) → LESS18_IN_G(T12)
The graph contains the following edges 1 > 1
(15) TRUE
(16) Obligation:
Pi DP problem:
The TRS P consists of the following rules:
LESS1_IN_GA(s(T10), s(T14)) → LESS1_IN_GA(T10, T14)
The TRS R consists of the following rules:
less1_in_ga(0, s(T6)) → less1_out_ga(0, s(T6))
less1_in_ga(s(s(T12)), 0) → U2_ga(T12, less18_in_g(T12))
less18_in_g(s(T12)) → U1_g(T12, less18_in_g(T12))
U1_g(T12, less18_out_g(T12)) → less18_out_g(s(T12))
U2_ga(T12, less18_out_g(T12)) → less1_out_ga(s(s(T12)), 0)
less1_in_ga(s(T10), s(T14)) → U3_ga(T10, T14, less1_in_ga(T10, T14))
less1_in_ga(s(T10), s(T16)) → U4_ga(T10, T16, less1_in_ga(T10, T16))
U4_ga(T10, T16, less1_out_ga(T10, T16)) → less1_out_ga(s(T10), s(T16))
U3_ga(T10, T14, less1_out_ga(T10, T14)) → less1_out_ga(s(T10), s(T14))
The argument filtering Pi contains the following mapping:
less1_in_ga(
x1,
x2) =
less1_in_ga(
x1)
0 =
0
less1_out_ga(
x1,
x2) =
less1_out_ga
s(
x1) =
s(
x1)
U2_ga(
x1,
x2) =
U2_ga(
x2)
less18_in_g(
x1) =
less18_in_g(
x1)
U1_g(
x1,
x2) =
U1_g(
x2)
less18_out_g(
x1) =
less18_out_g
U3_ga(
x1,
x2,
x3) =
U3_ga(
x3)
U4_ga(
x1,
x2,
x3) =
U4_ga(
x3)
LESS1_IN_GA(
x1,
x2) =
LESS1_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:
LESS1_IN_GA(s(T10), s(T14)) → LESS1_IN_GA(T10, T14)
R is empty.
The argument filtering Pi contains the following mapping:
s(
x1) =
s(
x1)
LESS1_IN_GA(
x1,
x2) =
LESS1_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:
LESS1_IN_GA(s(T10)) → LESS1_IN_GA(T10)
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:
- LESS1_IN_GA(s(T10)) → LESS1_IN_GA(T10)
The graph contains the following edges 1 > 1
(22) TRUE