/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# AProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty Termination w.r.t. Q of the given QTRS could be proven: (0) QTRS (1) Overlay + Local Confluence [EQUIVALENT, 0 ms] (2) QTRS (3) DependencyPairsProof [EQUIVALENT, 22 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) QDPSizeChangeProof [EQUIVALENT, 0 ms] (20) YES (21) QDP (22) UsableRulesProof [EQUIVALENT, 0 ms] (23) QDP (24) QReductionProof [EQUIVALENT, 0 ms] (25) QDP (26) QDPSizeChangeProof [EQUIVALENT, 0 ms] (27) YES (28) QDP (29) UsableRulesProof [EQUIVALENT, 0 ms] (30) QDP (31) QReductionProof [EQUIVALENT, 0 ms] (32) QDP (33) QDPSizeChangeProof [EQUIVALENT, 0 ms] (34) YES (35) QDP (36) UsableRulesProof [EQUIVALENT, 0 ms] (37) QDP (38) QReductionProof [EQUIVALENT, 0 ms] (39) QDP (40) NonInfProof [EQUIVALENT, 62 ms] (41) QDP (42) DependencyGraphProof [EQUIVALENT, 0 ms] (43) TRUE ---------------------------------------- (0) Obligation: Q restricted rewrite system: The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (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(x, y) TIMES(s(x), y) -> PLUS(y, times(x, y)) TIMES(s(x), y) -> TIMES(x, y) EXP(x, s(y)) -> TIMES(x, exp(x, y)) EXP(x, s(y)) -> EXP(x, y) GE(s(x), s(y)) -> GE(x, y) TOWER(x, y) -> TOWERITER(0, x, y, s(0)) TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) TOWERITER(c, x, y, z) -> GE(c, x) HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) HELP(false, c, x, y, z) -> EXP(y, z) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) 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 5 less nodes. ---------------------------------------- (6) Complex Obligation (AND) ---------------------------------------- (7) Obligation: Q DP problem: The TRS P consists of the following rules: GE(s(x), s(y)) -> GE(x, y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) 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: GE(s(x), s(y)) -> GE(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (11) Obligation: Q DP problem: The TRS P consists of the following rules: GE(s(x), s(y)) -> GE(x, y) 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: *GE(s(x), s(y)) -> GE(x, y) The graph contains the following edges 1 > 1, 2 > 2 ---------------------------------------- (13) YES ---------------------------------------- (14) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(x, y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) 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(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (18) Obligation: Q DP problem: The TRS P consists of the following rules: PLUS(s(x), y) -> PLUS(x, y) R is empty. Q is empty. We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (19) 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: *PLUS(s(x), y) -> PLUS(x, y) The graph contains the following edges 1 > 1, 2 >= 2 ---------------------------------------- (20) YES ---------------------------------------- (21) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(x, y) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (22) 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. ---------------------------------------- (23) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (24) 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (25) Obligation: Q DP problem: The TRS P consists of the following rules: TIMES(s(x), y) -> TIMES(x, y) R is empty. Q is empty. We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (26) 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: *TIMES(s(x), y) -> TIMES(x, y) The graph contains the following edges 1 > 1, 2 >= 2 ---------------------------------------- (27) YES ---------------------------------------- (28) 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(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (29) 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. ---------------------------------------- (30) 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (31) 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (32) 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. ---------------------------------------- (33) 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 ---------------------------------------- (34) YES ---------------------------------------- (35) Obligation: Q DP problem: The TRS P consists of the following rules: HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) The TRS R consists of the following rules: plus(0, x) -> x plus(s(x), y) -> s(plus(x, y)) times(0, y) -> 0 times(s(x), y) -> plus(y, times(x, y)) exp(x, 0) -> s(0) exp(x, s(y)) -> times(x, exp(x, y)) ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) tower(x, y) -> towerIter(0, x, y, s(0)) towerIter(c, x, y, z) -> help(ge(c, x), c, x, y, z) help(true, c, x, y, z) -> z help(false, c, x, y, z) -> towerIter(s(c), 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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (36) 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. ---------------------------------------- (37) Obligation: Q DP problem: The TRS P consists of the following rules: HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) 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(x, y)) plus(0, x) -> x plus(s(x), y) -> s(plus(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) tower(x0, x1) towerIter(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (38) 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(x0, x1, x2, x3) help(true, x0, x1, x2, x3) help(false, x0, x1, x2, x3) ---------------------------------------- (39) Obligation: Q DP problem: The TRS P consists of the following rules: HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) 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(x, y)) plus(0, x) -> x plus(s(x), y) -> s(plus(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (40) NonInfProof (EQUIVALENT) The DP Problem is simplified using the Induction Calculus [NONINF] with the following steps: Note that final constraints are written in bold face. For Pair HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) the following chains were created: *We consider the chain TOWERITER(x4, x5, x6, x7) -> HELP(ge(x4, x5), x4, x5, x6, x7), HELP(false, x8, x9, x10, x11) -> TOWERITER(s(x8), x9, x10, exp(x10, x11)) which results in the following constraint: (1) (HELP(ge(x4, x5), x4, x5, x6, x7)=HELP(false, x8, x9, x10, x11) ==> HELP(false, x8, x9, x10, x11)_>=_TOWERITER(s(x8), x9, x10, exp(x10, x11))) We simplified constraint (1) using rules (I), (II), (III) which results in the following new constraint: (2) (ge(x4, x5)=false ==> HELP(false, x4, x5, x6, x7)_>=_TOWERITER(s(x4), x5, x6, exp(x6, x7))) We simplified constraint (2) using rule (V) (with possible (I) afterwards) using induction on ge(x4, x5)=false which results in the following new constraints: (3) (false=false ==> HELP(false, 0, s(x25), x6, x7)_>=_TOWERITER(s(0), s(x25), x6, exp(x6, x7))) (4) (ge(x27, x26)=false & (\/x28,x29:ge(x27, x26)=false ==> HELP(false, x27, x26, x28, x29)_>=_TOWERITER(s(x27), x26, x28, exp(x28, x29))) ==> HELP(false, s(x27), s(x26), x6, x7)_>=_TOWERITER(s(s(x27)), s(x26), x6, exp(x6, x7))) We simplified constraint (3) using rules (I), (II) which results in the following new constraint: (5) (HELP(false, 0, s(x25), x6, x7)_>=_TOWERITER(s(0), s(x25), x6, exp(x6, x7))) We simplified constraint (4) using rule (VI) where we applied the induction hypothesis (\/x28,x29:ge(x27, x26)=false ==> HELP(false, x27, x26, x28, x29)_>=_TOWERITER(s(x27), x26, x28, exp(x28, x29))) with sigma = [x28 / x6, x29 / x7] which results in the following new constraint: (6) (HELP(false, x27, x26, x6, x7)_>=_TOWERITER(s(x27), x26, x6, exp(x6, x7)) ==> HELP(false, s(x27), s(x26), x6, x7)_>=_TOWERITER(s(s(x27)), s(x26), x6, exp(x6, x7))) For Pair TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) the following chains were created: *We consider the chain HELP(false, x12, x13, x14, x15) -> TOWERITER(s(x12), x13, x14, exp(x14, x15)), TOWERITER(x16, x17, x18, x19) -> HELP(ge(x16, x17), x16, x17, x18, x19) which results in the following constraint: (1) (TOWERITER(s(x12), x13, x14, exp(x14, x15))=TOWERITER(x16, x17, x18, x19) ==> TOWERITER(x16, x17, x18, x19)_>=_HELP(ge(x16, x17), x16, x17, x18, x19)) We simplified constraint (1) using rules (I), (II), (III), (IV) which results in the following new constraint: (2) (TOWERITER(s(x12), x13, x14, x19)_>=_HELP(ge(s(x12), x13), s(x12), x13, x14, x19)) To summarize, we get the following constraints P__>=_ for the following pairs. *HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) *(HELP(false, 0, s(x25), x6, x7)_>=_TOWERITER(s(0), s(x25), x6, exp(x6, x7))) *(HELP(false, x27, x26, x6, x7)_>=_TOWERITER(s(x27), x26, x6, exp(x6, x7)) ==> HELP(false, s(x27), s(x26), x6, x7)_>=_TOWERITER(s(s(x27)), s(x26), x6, exp(x6, x7))) *TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) *(TOWERITER(s(x12), x13, x14, x19)_>=_HELP(ge(s(x12), x13), s(x12), x13, x14, x19)) The constraints for P_> respective P_bound are constructed from P__>=_ where we just replace every occurence of "t _>=_ s" in P__>=_ by "t > s" respective "t _>=_ c". Here c stands for the fresh constant used for P_bound. Using the following integer polynomial ordering the resulting constraints can be solved Polynomial interpretation [NONINF]: POL(0) = 0 POL(HELP(x_1, x_2, x_3, x_4, x_5)) = -x_1 - x_2 + x_3 POL(TOWERITER(x_1, x_2, x_3, x_4)) = -1 - x_1 + x_2 POL(c) = -2 POL(exp(x_1, x_2)) = 1 + x_1 + x_2 POL(false) = 1 POL(ge(x_1, x_2)) = 1 POL(plus(x_1, x_2)) = x_2 POL(s(x_1)) = 1 + x_1 POL(times(x_1, x_2)) = 1 + x_1 + x_2 POL(true) = 1 The following pairs are in P_>: HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) The following pairs are in P_bound: HELP(false, c, x, y, z) -> TOWERITER(s(c), x, y, exp(y, z)) The following rules are usable: true -> ge(x, 0) false -> ge(0, s(x)) ge(x, y) -> ge(s(x), s(y)) ---------------------------------------- (41) Obligation: Q DP problem: The TRS P consists of the following rules: TOWERITER(c, x, y, z) -> HELP(ge(c, x), c, x, y, z) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(x)) -> false ge(s(x), s(y)) -> ge(x, y) 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(x, y)) plus(0, x) -> x plus(s(x), y) -> s(plus(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)) ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (42) DependencyGraphProof (EQUIVALENT) The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 1 less node. ---------------------------------------- (43) TRUE