/export/starexec/sandbox2/solver/bin/starexec_run_standard /export/starexec/sandbox2/benchmark/theBenchmark.xml /export/starexec/sandbox2/output/output_files -------------------------------------------------------------------------------- YES proof of /export/starexec/sandbox2/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# AProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty Termination w.r.t. Q of the given QTRS could be proven: (0) QTRS (1) Overlay + Local Confluence [EQUIVALENT, 0 ms] (2) QTRS (3) DependencyPairsProof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, 0 ms] (4) QDP (5) DependencyGraphProof [EQUIVALENT, 0 ms] (6) AND (7) QDP (8) UsableRulesProof [EQUIVALENT, 0 ms] (9) QDP (10) QReductionProof [EQUIVALENT, 1 ms] (11) QDP (12) QDPSizeChangeProof [EQUIVALENT, 0 ms] (13) YES (14) QDP (15) UsableRulesProof [EQUIVALENT, 1 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, 1 ms] (32) QDP (33) NonInfProof [EQUIVALENT, 52 ms] (34) QDP (35) DependencyGraphProof [EQUIVALENT, 0 ms] (36) TRUE ---------------------------------------- (0) Obligation: Q restricted rewrite system: The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) 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: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) ---------------------------------------- (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: GE(s(x), s(y)) -> GE(x, y) REV(x) -> IF(x, eq(0, length(x)), nil, 0, length(x)) REV(x) -> LENGTH(x) IF(x, false, z, c, l) -> HELP(s(c), l, x, z) HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) HELP(c, l, cons(x, y), z) -> APPEND(y, cons(x, nil)) HELP(c, l, cons(x, y), z) -> GE(c, l) APPEND(cons(x, y), z) -> APPEND(y, z) LENGTH(cons(x, y)) -> LENGTH(y) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (5) DependencyGraphProof (EQUIVALENT) The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 4 SCCs with 4 less nodes. ---------------------------------------- (6) Complex Obligation (AND) ---------------------------------------- (7) Obligation: Q DP problem: The TRS P consists of the following rules: LENGTH(cons(x, y)) -> LENGTH(y) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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: LENGTH(cons(x, y)) -> LENGTH(y) R is empty. The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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]. ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) ---------------------------------------- (11) Obligation: Q DP problem: The TRS P consists of the following rules: LENGTH(cons(x, y)) -> LENGTH(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: *LENGTH(cons(x, y)) -> LENGTH(y) The graph contains the following edges 1 > 1 ---------------------------------------- (13) YES ---------------------------------------- (14) Obligation: Q DP problem: The TRS P consists of the following rules: APPEND(cons(x, y), z) -> APPEND(y, z) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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: APPEND(cons(x, y), z) -> APPEND(y, z) R is empty. The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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]. ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) ---------------------------------------- (18) Obligation: Q DP problem: The TRS P consists of the following rules: APPEND(cons(x, y), z) -> APPEND(y, z) 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: *APPEND(cons(x, y), z) -> APPEND(y, z) 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: GE(s(x), s(y)) -> GE(x, y) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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: GE(s(x), s(y)) -> GE(x, y) R is empty. The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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]. ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) ---------------------------------------- (25) 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. ---------------------------------------- (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: *GE(s(x), s(y)) -> GE(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: HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) IF(x, false, z, c, l) -> HELP(s(c), l, x, z) The TRS R consists of the following rules: ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) rev(x) -> if(x, eq(0, length(x)), nil, 0, length(x)) if(x, true, z, c, l) -> z if(x, false, z, c, l) -> help(s(c), l, x, z) help(c, l, cons(x, y), z) -> if(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) length(nil) -> 0 length(cons(x, y)) -> s(length(y)) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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: HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) IF(x, false, z, c, l) -> HELP(s(c), l, x, z) The TRS R consists of the following rules: append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) append(nil, x0) append(cons(x0, x1), x2) length(nil) length(cons(x0, x1)) 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]. rev(x0) if(x0, true, x1, x2, x3) if(x0, false, x1, x2, x3) help(x0, x1, cons(x2, x3), x4) length(nil) length(cons(x0, x1)) ---------------------------------------- (32) Obligation: Q DP problem: The TRS P consists of the following rules: HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) IF(x, false, z, c, l) -> HELP(s(c), l, x, z) The TRS R consists of the following rules: append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) append(nil, x0) append(cons(x0, x1), x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (33) 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(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) the following chains were created: *We consider the chain IF(x5, false, x6, x7, x8) -> HELP(s(x7), x8, x5, x6), HELP(x9, x10, cons(x11, x12), x13) -> IF(append(x12, cons(x11, nil)), ge(x9, x10), cons(x11, x13), x9, x10) which results in the following constraint: (1) (HELP(s(x7), x8, x5, x6)=HELP(x9, x10, cons(x11, x12), x13) ==> HELP(x9, x10, cons(x11, x12), x13)_>=_IF(append(x12, cons(x11, nil)), ge(x9, x10), cons(x11, x13), x9, x10)) We simplified constraint (1) using rules (I), (II), (III) which results in the following new constraint: (2) (HELP(s(x7), x8, cons(x11, x12), x6)_>=_IF(append(x12, cons(x11, nil)), ge(s(x7), x8), cons(x11, x6), s(x7), x8)) For Pair IF(x, false, z, c, l) -> HELP(s(c), l, x, z) the following chains were created: *We consider the chain HELP(x14, x15, cons(x16, x17), x18) -> IF(append(x17, cons(x16, nil)), ge(x14, x15), cons(x16, x18), x14, x15), IF(x19, false, x20, x21, x22) -> HELP(s(x21), x22, x19, x20) which results in the following constraint: (1) (IF(append(x17, cons(x16, nil)), ge(x14, x15), cons(x16, x18), x14, x15)=IF(x19, false, x20, x21, x22) ==> IF(x19, false, x20, x21, x22)_>=_HELP(s(x21), x22, x19, x20)) We simplified constraint (1) using rules (I), (II), (III), (VII) which results in the following new constraint: (2) (cons(x16, nil)=x27 & append(x17, x27)=x19 & ge(x14, x15)=false ==> IF(x19, false, cons(x16, x18), x14, x15)_>=_HELP(s(x14), x15, x19, cons(x16, x18))) We simplified constraint (2) using rule (V) (with possible (I) afterwards) using induction on ge(x14, x15)=false which results in the following new constraints: (3) (false=false & cons(x16, nil)=x27 & append(x17, x27)=x19 ==> IF(x19, false, cons(x16, x18), 0, s(x29))_>=_HELP(s(0), s(x29), x19, cons(x16, x18))) (4) (ge(x31, x30)=false & cons(x16, nil)=x27 & append(x17, x27)=x19 & (\/x32,x33,x34,x35,x36:ge(x31, x30)=false & cons(x32, nil)=x33 & append(x34, x33)=x35 ==> IF(x35, false, cons(x32, x36), x31, x30)_>=_HELP(s(x31), x30, x35, cons(x32, x36))) ==> IF(x19, false, cons(x16, x18), s(x31), s(x30))_>=_HELP(s(s(x31)), s(x30), x19, cons(x16, x18))) We simplified constraint (3) using rules (I), (II), (III), (IV) which results in the following new constraint: (5) (IF(x19, false, cons(x16, x18), 0, s(x29))_>=_HELP(s(0), s(x29), x19, cons(x16, x18))) We simplified constraint (4) using rule (VI) where we applied the induction hypothesis (\/x32,x33,x34,x35,x36:ge(x31, x30)=false & cons(x32, nil)=x33 & append(x34, x33)=x35 ==> IF(x35, false, cons(x32, x36), x31, x30)_>=_HELP(s(x31), x30, x35, cons(x32, x36))) with sigma = [x32 / x16, x33 / x27, x34 / x17, x35 / x19, x36 / x18] which results in the following new constraint: (6) (IF(x19, false, cons(x16, x18), x31, x30)_>=_HELP(s(x31), x30, x19, cons(x16, x18)) ==> IF(x19, false, cons(x16, x18), s(x31), s(x30))_>=_HELP(s(s(x31)), s(x30), x19, cons(x16, x18))) To summarize, we get the following constraints P__>=_ for the following pairs. *HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) *(HELP(s(x7), x8, cons(x11, x12), x6)_>=_IF(append(x12, cons(x11, nil)), ge(s(x7), x8), cons(x11, x6), s(x7), x8)) *IF(x, false, z, c, l) -> HELP(s(c), l, x, z) *(IF(x19, false, cons(x16, x18), x31, x30)_>=_HELP(s(x31), x30, x19, cons(x16, x18)) ==> IF(x19, false, cons(x16, x18), s(x31), s(x30))_>=_HELP(s(s(x31)), s(x30), x19, cons(x16, x18))) *(IF(x19, false, cons(x16, x18), 0, s(x29))_>=_HELP(s(0), s(x29), x19, cons(x16, x18))) 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)) = -1 - x_1 + x_2 - x_3 POL(IF(x_1, x_2, x_3, x_4, x_5)) = -1 + x_1 - x_2 - x_3 - x_4 + x_5 POL(append(x_1, x_2)) = x_2 POL(c) = -2 POL(cons(x_1, x_2)) = 0 POL(false) = 0 POL(ge(x_1, x_2)) = 0 POL(nil) = 0 POL(s(x_1)) = 1 + x_1 POL(true) = 0 The following pairs are in P_>: IF(x, false, z, c, l) -> HELP(s(c), l, x, z) The following pairs are in P_bound: IF(x, false, z, c, l) -> HELP(s(c), l, x, z) The following rules are usable: append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) true -> ge(x, 0) false -> ge(0, s(y)) ge(x, y) -> ge(s(x), s(y)) ---------------------------------------- (34) Obligation: Q DP problem: The TRS P consists of the following rules: HELP(c, l, cons(x, y), z) -> IF(append(y, cons(x, nil)), ge(c, l), cons(x, z), c, l) The TRS R consists of the following rules: append(nil, y) -> y append(cons(x, y), z) -> cons(x, append(y, z)) ge(x, 0) -> true ge(0, s(y)) -> false ge(s(x), s(y)) -> ge(x, y) The set Q consists of the following terms: ge(x0, 0) ge(0, s(x0)) ge(s(x0), s(x1)) append(nil, x0) append(cons(x0, x1), x2) We have to consider all minimal (P,Q,R)-chains. ---------------------------------------- (35) DependencyGraphProof (EQUIVALENT) The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 1 less node. ---------------------------------------- (36) TRUE