/export/starexec/sandbox/solver/bin/starexec_run_standard /export/starexec/sandbox/benchmark/theBenchmark.xml /export/starexec/sandbox/output/output_files -------------------------------------------------------------------------------- YES proof of /export/starexec/sandbox/benchmark/theBenchmark.xml # AProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty Termination w.r.t. Q of the given QTRS could be proven: (0) QTRS (1) Overlay + Local Confluence [EQUIVALENT, 15 ms] (2) QTRS (3) DependencyPairsProof [EQUIVALENT, 0 ms] (4) QDP (5) DependencyGraphProof [EQUIVALENT, 0 ms] (6) AND (7) QDP (8) UsableRulesProof [EQUIVALENT, 0 ms] (9) QDP (10) QReductionProof [EQUIVALENT, 0 ms] (11) QDP (12) QDPSizeChangeProof [EQUIVALENT, 0 ms] (13) YES (14) QDP (15) UsableRulesProof [EQUIVALENT, 0 ms] (16) QDP (17) QReductionProof [EQUIVALENT, 0 ms] (18) QDP (19) MRRProof [EQUIVALENT, 14 ms] (20) QDP (21) QDPOrderProof [EQUIVALENT, 0 ms] (22) QDP (23) PisEmptyProof [EQUIVALENT, 0 ms] (24) YES (25) QDP (26) UsableRulesProof [EQUIVALENT, 0 ms] (27) QDP (28) QReductionProof [EQUIVALENT, 0 ms] (29) QDP (30) MRRProof [EQUIVALENT, 9 ms] (31) QDP (32) QDPOrderProof [EQUIVALENT, 11 ms] (33) QDP (34) PisEmptyProof [EQUIVALENT, 0 ms] (35) YES (36) QDP (37) UsableRulesProof [EQUIVALENT, 0 ms] (38) QDP (39) QReductionProof [EQUIVALENT, 0 ms] (40) QDP (41) QDPSizeChangeProof [EQUIVALENT, 0 ms] (42) YES (43) QDP (44) UsableRulesProof [EQUIVALENT, 0 ms] (45) QDP (46) QReductionProof [EQUIVALENT, 0 ms] (47) QDP (48) QDPOrderProof [EQUIVALENT, 0 ms] (49) QDP (50) PisEmptyProof [EQUIVALENT, 0 ms] (51) YES ---------------------------------------- (0) Obligation: Q restricted rewrite system: The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) Q is empty. ---------------------------------------- (1) Overlay + Local Confluence (EQUIVALENT) The TRS is overlay and locally confluent. By [NOC] we can switch to innermost. ---------------------------------------- (2) Obligation: Q restricted rewrite system: The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (3) DependencyPairsProof (EQUIVALENT) Using Dependency Pairs [AG00,LPAR04] we result in the following initial DP problem. ---------------------------------------- (4) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(p(s(x)), y) PLUS(s(x), y) -> P(s(x)) TIMES(s(x), y) -> PLUS(y, times(p(s(x)), y)) TIMES(s(x), y) -> TIMES(p(s(x)), y) TIMES(s(x), y) -> P(s(x)) EXP(x, s(y)) -> TIMES(x, exp(x, y)) EXP(x, s(y)) -> EXP(x, y) P(s(s(x))) -> P(s(x)) TOWER(x, y) -> TOWERITER(x, y, s(0)) TOWERITER(s(x), y, z) -> TOWERITER(p(s(x)), y, exp(y, z)) TOWERITER(s(x), y, z) -> P(s(x)) TOWERITER(s(x), y, z) -> EXP(y, z) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (5) DependencyGraphProof (EQUIVALENT) The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 5 SCCs with 7 less nodes. ---------------------------------------- (6) Complex Obligation (AND) ---------------------------------------- (7) Obligation: Q DP problem: The TRS P consists of the following rules: P(s(s(x))) -> P(s(x)) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (8) UsableRulesProof (EQUIVALENT) As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R. ---------------------------------------- (9) Obligation: Q DP problem: The TRS P consists of the following rules: P(s(s(x))) -> P(s(x)) R is empty. The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (10) QReductionProof (EQUIVALENT) We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN]. plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (11) Obligation: Q DP problem: The TRS P consists of the following rules: P(s(s(x))) -> P(s(x)) R is empty. Q is empty. We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (12) 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: *P(s(s(x))) -> P(s(x)) The graph contains the following edges 1 > 1 ---------------------------------------- (13) YES ---------------------------------------- (14) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(p(s(x)), y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (15) UsableRulesProof (EQUIVALENT) As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R. ---------------------------------------- (16) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(p(s(x)), y) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (17) QReductionProof (EQUIVALENT) We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN]. plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (18) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(p(s(x)), y) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (19) MRRProof (EQUIVALENT) By using the rule removal processor [LPAR04] with the following ordering, at least one Dependency Pair or term rewrite system rule of this QDP problem can be strictly oriented. Strictly oriented rules of the TRS R: p(s(0)) -> 0 Used ordering: Polynomial interpretation [POLO]: POL(0) = 2 POL(PLUS(x_1, x_2)) = x_1 + x_2 POL(p(x_1)) = x_1 POL(s(x_1)) = 2*x_1 ---------------------------------------- (20) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(p(s(x)), y) The TRS R consists of the following rules: p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (21) QDPOrderProof (EQUIVALENT) We use the reduction pair processor [LPAR04,JAR06]. The following pairs can be oriented strictly and are deleted. PLUS(s(x), y) -> PLUS(p(s(x)), y) The remaining pairs can at least be oriented weakly. Used ordering: Polynomial Order [NEGPOLO,POLO] with Interpretation: POL( PLUS_2(x_1, x_2) ) = 2x_1 + 2 POL( p_1(x_1) ) = max{0, x_1 - 1} POL( s_1(x_1) ) = 2x_1 + 2 The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented: p(s(s(x))) -> s(p(s(x))) ---------------------------------------- (22) Obligation: Q DP problem: P is empty. The TRS R consists of the following rules: p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (23) PisEmptyProof (EQUIVALENT) The TRS P is empty. Hence, there is no (P,Q,R) chain. ---------------------------------------- (24) YES ---------------------------------------- (25) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(p(s(x)), y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (26) UsableRulesProof (EQUIVALENT) As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R. ---------------------------------------- (27) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(p(s(x)), y) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (28) QReductionProof (EQUIVALENT) We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN]. plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (29) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(p(s(x)), y) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (30) MRRProof (EQUIVALENT) By using the rule removal processor [LPAR04] with the following ordering, at least one Dependency Pair or term rewrite system rule of this QDP problem can be strictly oriented. Strictly oriented rules of the TRS R: p(s(0)) -> 0 Used ordering: Polynomial interpretation [POLO]: POL(0) = 2 POL(TIMES(x_1, x_2)) = x_1 + x_2 POL(p(x_1)) = x_1 POL(s(x_1)) = 2*x_1 ---------------------------------------- (31) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(p(s(x)), y) The TRS R consists of the following rules: p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (32) QDPOrderProof (EQUIVALENT) We use the reduction pair processor [LPAR04,JAR06]. The following pairs can be oriented strictly and are deleted. TIMES(s(x), y) -> TIMES(p(s(x)), y) The remaining pairs can at least be oriented weakly. Used ordering: Polynomial Order [NEGPOLO,POLO] with Interpretation: POL( TIMES_2(x_1, x_2) ) = 2x_1 + 2 POL( p_1(x_1) ) = max{0, x_1 - 1} POL( s_1(x_1) ) = 2x_1 + 2 The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented: p(s(s(x))) -> s(p(s(x))) ---------------------------------------- (33) Obligation: Q DP problem: P is empty. The TRS R consists of the following rules: p(s(s(x))) -> s(p(s(x))) The set Q consists of the following terms: p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (34) PisEmptyProof (EQUIVALENT) The TRS P is empty. Hence, there is no (P,Q,R) chain. ---------------------------------------- (35) YES ---------------------------------------- (36) Obligation: Q DP problem: The TRS P consists of the following rules: EXP(x, s(y)) -> EXP(x, y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (37) UsableRulesProof (EQUIVALENT) As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R. ---------------------------------------- (38) Obligation: Q DP problem: The TRS P consists of the following rules: EXP(x, s(y)) -> EXP(x, y) R is empty. The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (39) QReductionProof (EQUIVALENT) We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN]. plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (40) Obligation: Q DP problem: The TRS P consists of the following rules: EXP(x, s(y)) -> EXP(x, y) R is empty. Q is empty. We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (41) 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: *EXP(x, s(y)) -> EXP(x, y) The graph contains the following edges 1 >= 1, 2 > 2 ---------------------------------------- (42) YES ---------------------------------------- (43) Obligation: Q DP problem: The TRS P consists of the following rules: TOWERITER(s(x), y, z) -> TOWERITER(p(s(x)), y, exp(y, z)) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) tower(x, y) -> towerIter(x, y, s(0)) towerIter(0, y, z) -> z towerIter(s(x), y, z) -> towerIter(p(s(x)), y, exp(y, z)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (44) UsableRulesProof (EQUIVALENT) As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [LPAR04] we can delete all non-usable rules [FROCOS05] from R. ---------------------------------------- (45) Obligation: Q DP problem: The TRS P consists of the following rules: TOWERITER(s(x), y, z) -> TOWERITER(p(s(x)), y, exp(y, z)) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (46) QReductionProof (EQUIVALENT) We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.[THIEMANN]. tower(x0, x1) towerIter(0, x0, x1) towerIter(s(x0), x1, x2) ---------------------------------------- (47) Obligation: Q DP problem: The TRS P consists of the following rules: TOWERITER(s(x), y, z) -> TOWERITER(p(s(x)), y, exp(y, z)) The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (48) QDPOrderProof (EQUIVALENT) We use the reduction pair processor [LPAR04,JAR06]. The following pairs can be oriented strictly and are deleted. TOWERITER(s(x), y, z) -> TOWERITER(p(s(x)), y, exp(y, z)) The remaining pairs can at least be oriented weakly. Used ordering: Polynomial Order [NEGPOLO,POLO] with Interpretation: POL( TOWERITER_3(x_1, ..., x_3) ) = x_1 + 1 POL( plus_2(x_1, x_2) ) = max{0, 2x_2 - 2} POL( s_1(x_1) ) = x_1 + 1 POL( times_2(x_1, x_2) ) = x_2 + 2 POL( p_1(x_1) ) = max{0, x_1 - 1} POL( 0 ) = 0 POL( exp_2(x_1, x_2) ) = 2 The following usable rules [FROCOS05] with respect to the argument filtering of the ordering [JAR06] were oriented: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) ---------------------------------------- (49) Obligation: Q DP problem: P is empty. The TRS R consists of the following rules: p(s(0)) -> 0 p(s(s(x))) -> s(p(s(x))) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(p(s(x)), y)) plus(0, x) -> x plus(s(x), y) -> s(plus(p(s(x)), y)) The set Q consists of the following terms: plus(0, x0) plus(s(x0), x1) times(0, x0) times(s(x0), x1) exp(x0, 0) exp(x0, s(x1)) p(s(0)) p(s(s(x0))) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (50) PisEmptyProof (EQUIVALENT) The TRS P is empty. Hence, there is no (P,Q,R) chain. ---------------------------------------- (51) YES