3.62/2.14 YES 3.62/2.15 We consider the system theBenchmark. 3.62/2.15 3.62/2.15 Alphabet: 3.62/2.15 3.62/2.15 0 : [] --> nat 3.62/2.15 app : [natlist * natlist] --> natlist 3.62/2.15 apply2 : [pair -> nat -> pair * pair * nat] --> pair 3.62/2.15 cons : [nat * natlist] --> natlist 3.62/2.15 fst : [pair] --> natlist 3.62/2.15 nil : [] --> natlist 3.62/2.15 p : [natlist * natlist] --> pair 3.62/2.15 pcons : [pair * plist] --> plist 3.62/2.15 pnil : [] --> plist 3.62/2.15 pps : [natlist] --> plist 3.62/2.15 prefixshuffle : [pair * natlist] --> plist 3.62/2.15 pshuffle : [natlist] --> pair 3.62/2.15 reverse : [natlist] --> natlist 3.62/2.15 s : [nat] --> nat 3.62/2.15 shuffle : [natlist] --> natlist 3.62/2.15 3.62/2.15 Rules: 3.62/2.15 3.62/2.15 app(nil, x) => x 3.62/2.15 app(cons(x, y), z) => cons(x, app(y, z)) 3.62/2.15 reverse(nil) => nil 3.62/2.15 reverse(cons(x, y)) => app(reverse(y), cons(x, nil)) 3.62/2.15 shuffle(nil) => nil 3.62/2.15 shuffle(cons(x, y)) => cons(x, shuffle(reverse(y))) 3.62/2.15 fst(p(x, y)) => x 3.62/2.15 pshuffle(x) => p(x, shuffle(x)) 3.62/2.15 prefixshuffle(x, nil) => pcons(x, pnil) 3.62/2.15 prefixshuffle(x, cons(y, z)) => pcons(x, prefixshuffle(apply2(/\u./\v.pshuffle(app(fst(u), cons(v, nil))), x, y), reverse(z))) 3.62/2.16 apply2(f, x, 0) => x 3.62/2.16 apply2(f, x, s(y)) => f x s(y) 3.62/2.16 pps(x) => prefixshuffle(p(nil, nil), x) 3.62/2.16 3.62/2.16 This AFS is converted to an AFSM simply by replacing all free variables by meta-variables (with arity 0). 3.62/2.16 3.62/2.16 We observe that the rules contain a first-order subset: 3.62/2.16 3.62/2.16 app(nil, X) => X 3.62/2.16 app(cons(X, Y), Z) => cons(X, app(Y, Z)) 3.62/2.16 reverse(nil) => nil 3.62/2.16 reverse(cons(X, Y)) => app(reverse(Y), cons(X, nil)) 3.62/2.16 shuffle(nil) => nil 3.62/2.16 shuffle(cons(X, Y)) => cons(X, shuffle(reverse(Y))) 3.62/2.16 fst(p(X, Y)) => X 3.62/2.16 pshuffle(X) => p(X, shuffle(X)) 3.62/2.16 3.62/2.16 Moreover, the system is orthogonal. Thus, by [Kop12, Thm. 7.55], we may omit all first-order dependency pairs from the dependency pair problem (DP(R), R) if this first-order part is terminating when seen as a many-sorted first-order TRS. 3.62/2.16 3.62/2.16 According to the external first-order termination prover, this system is indeed terminating: 3.62/2.16 3.62/2.16 || proof of resources/system.trs 3.62/2.16 || # AProVE Commit ID: d84c10301d352dfd14de2104819581f4682260f5 fuhs 20130616 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || Termination w.r.t. Q of the given QTRS could be proven: 3.62/2.16 || 3.62/2.16 || (0) QTRS 3.62/2.16 || (1) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (2) QTRS 3.62/2.16 || (3) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (4) QTRS 3.62/2.16 || (5) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (6) QTRS 3.62/2.16 || (7) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (8) QTRS 3.62/2.16 || (9) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (10) QTRS 3.62/2.16 || (11) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (12) QTRS 3.62/2.16 || (13) QTRSRRRProof [EQUIVALENT] 3.62/2.16 || (14) QTRS 3.62/2.16 || (15) RisEmptyProof [EQUIVALENT] 3.62/2.16 || (16) YES 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (0) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || shuffle(nil) -> nil 3.62/2.16 || shuffle(cons(%X, %Y)) -> cons(%X, shuffle(reverse(%Y))) 3.62/2.16 || fst(p(%X, %Y)) -> %X 3.62/2.16 || pshuffle(%X) -> p(%X, shuffle(%X)) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (1) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(cons(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(fst(x_1)) = 2 + x_1 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(p(x_1, x_2)) = 2 + x_1 + x_2 3.62/2.16 || POL(pshuffle(x_1)) = 2 + 2*x_1 3.62/2.16 || POL(reverse(x_1)) = x_1 3.62/2.16 || POL(shuffle(x_1)) = x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || fst(p(%X, %Y)) -> %X 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (2) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || shuffle(nil) -> nil 3.62/2.16 || shuffle(cons(%X, %Y)) -> cons(%X, shuffle(reverse(%Y))) 3.62/2.16 || pshuffle(%X) -> p(%X, shuffle(%X)) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (3) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(cons(x_1, x_2)) = 2*x_1 + x_2 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(p(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(pshuffle(x_1)) = 1 + 2*x_1 3.62/2.16 || POL(reverse(x_1)) = x_1 3.62/2.16 || POL(shuffle(x_1)) = x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || pshuffle(%X) -> p(%X, shuffle(%X)) 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (4) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || shuffle(nil) -> nil 3.62/2.16 || shuffle(cons(%X, %Y)) -> cons(%X, shuffle(reverse(%Y))) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (5) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(cons(x_1, x_2)) = 2 + 2*x_1 + x_2 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(reverse(x_1)) = x_1 3.62/2.16 || POL(shuffle(x_1)) = 2*x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || shuffle(cons(%X, %Y)) -> cons(%X, shuffle(reverse(%Y))) 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (6) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || shuffle(nil) -> nil 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (7) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + 2*x_2 3.62/2.16 || POL(cons(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(reverse(x_1)) = 2*x_1 3.62/2.16 || POL(shuffle(x_1)) = 1 + 2*x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || shuffle(nil) -> nil 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (8) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (9) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(cons(x_1, x_2)) = 1 + 2*x_1 + x_2 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(reverse(x_1)) = 1 + x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || reverse(nil) -> nil 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (10) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (11) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Polynomial interpretation [POLO]: 3.62/2.16 || 3.62/2.16 || POL(app(x_1, x_2)) = x_1 + x_2 3.62/2.16 || POL(cons(x_1, x_2)) = 1 + 2*x_1 + x_2 3.62/2.16 || POL(nil) = 0 3.62/2.16 || POL(reverse(x_1)) = 2*x_1 3.62/2.16 || With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || reverse(cons(%X, %Y)) -> app(reverse(%Y), cons(%X, nil)) 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (12) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || The TRS R consists of the following rules: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (13) QTRSRRRProof (EQUIVALENT) 3.62/2.16 || Used ordering: 3.62/2.16 || Knuth-Bendix order [KBO] with precedence:app_2 > cons_2 > nil 3.62/2.16 || 3.62/2.16 || and weight map: 3.62/2.16 || 3.62/2.16 || nil=1 3.62/2.16 || app_2=0 3.62/2.16 || cons_2=0 3.62/2.16 || 3.62/2.16 || The variable weight is 1With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly: 3.62/2.16 || 3.62/2.16 || app(nil, %X) -> %X 3.62/2.16 || app(cons(%X, %Y), %Z) -> cons(%X, app(%Y, %Z)) 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (14) 3.62/2.16 || Obligation: 3.62/2.16 || Q restricted rewrite system: 3.62/2.16 || R is empty. 3.62/2.16 || Q is empty. 3.62/2.16 || 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (15) RisEmptyProof (EQUIVALENT) 3.62/2.16 || The TRS R is empty. Hence, termination is trivially proven. 3.62/2.16 || ---------------------------------------- 3.62/2.16 || 3.62/2.16 || (16) 3.62/2.16 || YES 3.62/2.16 || 3.62/2.16 We use the dependency pair framework as described in [Kop12, Ch. 6/7], with static dependency pairs (see [KusIsoSakBla09] and the adaptation for AFSMs and accessible arguments in [Kop13]). 3.62/2.16 3.62/2.16 We thus obtain the following dependency pair problem (P_0, R_0, static, formative): 3.62/2.16 3.62/2.16 Dependency Pairs P_0: 3.62/2.16 3.62/2.16 0] prefixshuffle#(X, cons(Y, Z)) =#> prefixshuffle#(apply2(/\x./\y.pshuffle(app(fst(x), cons(y, nil))), X, Y), reverse(Z)) 3.62/2.16 1] prefixshuffle#(X, cons(Y, Z)) =#> apply2#(/\x./\y.pshuffle(app(fst(x), cons(y, nil))), X, Y) 3.62/2.16 2] prefixshuffle#(X, cons(Y, Z)) =#> pshuffle#(app(fst(U), cons(V, nil))) 3.62/2.16 3] prefixshuffle#(X, cons(Y, Z)) =#> app#(fst(U), cons(V, nil)) 3.62/2.16 4] prefixshuffle#(X, cons(Y, Z)) =#> fst#(U) 3.62/2.16 5] prefixshuffle#(X, cons(Y, Z)) =#> reverse#(Z) 3.62/2.16 6] pps#(X) =#> prefixshuffle#(p(nil, nil), X) 3.62/2.16 3.62/2.16 Rules R_0: 3.62/2.16 3.62/2.16 app(nil, X) => X 3.62/2.16 app(cons(X, Y), Z) => cons(X, app(Y, Z)) 3.62/2.16 reverse(nil) => nil 3.62/2.16 reverse(cons(X, Y)) => app(reverse(Y), cons(X, nil)) 3.62/2.16 shuffle(nil) => nil 3.62/2.16 shuffle(cons(X, Y)) => cons(X, shuffle(reverse(Y))) 3.62/2.16 fst(p(X, Y)) => X 3.62/2.16 pshuffle(X) => p(X, shuffle(X)) 3.62/2.16 prefixshuffle(X, nil) => pcons(X, pnil) 3.62/2.16 prefixshuffle(X, cons(Y, Z)) => pcons(X, prefixshuffle(apply2(/\x./\y.pshuffle(app(fst(x), cons(y, nil))), X, Y), reverse(Z))) 3.62/2.16 apply2(F, X, 0) => X 3.62/2.16 apply2(F, X, s(Y)) => F X s(Y) 3.62/2.16 pps(X) => prefixshuffle(p(nil, nil), X) 3.62/2.16 3.62/2.16 Thus, the original system is terminating if (P_0, R_0, static, formative) is finite. 3.62/2.16 3.62/2.16 We consider the dependency pair problem (P_0, R_0, static, formative). 3.62/2.16 3.62/2.16 We place the elements of P in a dependency graph approximation G (see e.g. [Kop12, Thm. 7.27, 7.29], as follows: 3.62/2.16 3.62/2.16 * 0 : 0, 1, 2, 3, 4, 5 3.62/2.16 * 1 : 3.62/2.16 * 2 : 3.62/2.16 * 3 : 3.62/2.16 * 4 : 3.62/2.16 * 5 : 3.62/2.16 * 6 : 0, 1, 2, 3, 4, 5 3.62/2.16 3.62/2.16 This graph has the following strongly connected components: 3.62/2.16 3.62/2.16 P_1: 3.62/2.16 3.62/2.16 prefixshuffle#(X, cons(Y, Z)) =#> prefixshuffle#(apply2(/\x./\y.pshuffle(app(fst(x), cons(y, nil))), X, Y), reverse(Z)) 3.62/2.16 3.62/2.16 By [Kop12, Thm. 7.31], we may replace any dependency pair problem (P_0, R_0, m, f) by (P_1, R_0, m, f). 3.62/2.16 3.62/2.16 Thus, the original system is terminating if (P_1, R_0, static, formative) is finite. 3.62/2.16 3.62/2.16 We consider the dependency pair problem (P_1, R_0, static, formative). 3.62/2.16 3.62/2.16 The formative rules of (P_1, R_0) are R_1 ::= 3.62/2.16 3.62/2.16 app(nil, X) => X 3.62/2.16 app(cons(X, Y), Z) => cons(X, app(Y, Z)) 3.62/2.16 reverse(nil) => nil 3.62/2.16 reverse(cons(X, Y)) => app(reverse(Y), cons(X, nil)) 3.62/2.16 shuffle(nil) => nil 3.62/2.16 shuffle(cons(X, Y)) => cons(X, shuffle(reverse(Y))) 3.62/2.16 fst(p(X, Y)) => X 3.62/2.16 pshuffle(X) => p(X, shuffle(X)) 3.62/2.16 apply2(F, X, 0) => X 3.62/2.16 apply2(F, X, s(Y)) => F X s(Y) 3.62/2.16 3.62/2.16 By [Kop12, Thm. 7.17], we may replace the dependency pair problem (P_1, R_0, static, formative) by (P_1, R_1, static, formative). 3.62/2.16 3.62/2.16 Thus, the original system is terminating if (P_1, R_1, static, formative) is finite. 3.62/2.16 3.62/2.16 We consider the dependency pair problem (P_1, R_1, static, formative). 3.62/2.16 3.62/2.16 We will use the reduction pair processor [Kop12, Thm. 7.16]. It suffices to find a standard reduction pair [Kop12, Def. 6.69]. Thus, we must orient: 3.62/2.16 3.62/2.16 prefixshuffle#(X, cons(Y, Z)) >? prefixshuffle#(apply2(/\x./\y.pshuffle(app(fst(x), cons(y, nil))), X, Y), reverse(Z)) 3.62/2.16 app(nil, X) >= X 3.62/2.16 app(cons(X, Y), Z) >= cons(X, app(Y, Z)) 3.62/2.16 reverse(nil) >= nil 3.62/2.16 reverse(cons(X, Y)) >= app(reverse(Y), cons(X, nil)) 3.62/2.16 shuffle(nil) >= nil 3.62/2.16 shuffle(cons(X, Y)) >= cons(X, shuffle(reverse(Y))) 3.62/2.16 fst(p(X, Y)) >= X 3.62/2.16 pshuffle(X) >= p(X, shuffle(X)) 3.62/2.16 apply2(F, X, 0) >= X 3.62/2.16 apply2(F, X, s(Y)) >= F X s(Y) 3.62/2.16 3.62/2.16 We apply [Kop12, Thm. 6.75] and use the following argument functions: 3.62/2.16 3.62/2.16 pi( pshuffle(X) ) = #argfun-pshuffle#(p(X, shuffle(X))) 3.62/2.16 3.62/2.16 We orient these requirements with a polynomial interpretation in the natural numbers. 3.62/2.16 3.62/2.16 The following interpretation satisfies the requirements: 3.62/2.16 3.62/2.16 #argfun-pshuffle# = \y0.y0 3.62/2.16 0 = 0 3.62/2.16 app = \y0y1.y0 + y1 3.62/2.16 apply2 = \G0y1y2.y1 + G0(y1,y1) 3.62/2.16 cons = \y0y1.1 + y1 3.62/2.16 fst = \y0.y0 3.62/2.16 nil = 0 3.62/2.16 p = \y0y1.y0 3.62/2.16 prefixshuffle# = \y0y1.2y1 3.62/2.16 pshuffle = \y0.0 3.62/2.16 reverse = \y0.y0 3.62/2.16 s = \y0.0 3.62/2.16 shuffle = \y0.2y0 3.62/2.16 3.62/2.16 Using this interpretation, the requirements translate to: 3.62/2.16 3.62/2.16 [[prefixshuffle#(_x0, cons(_x1, _x2))]] = 2 + 2x2 > 2x2 = [[prefixshuffle#(apply2(/\x./\y.#argfun-pshuffle#(p(app(fst(x), cons(y, nil)), shuffle(app(fst(x), cons(y, nil))))), _x0, _x1), reverse(_x2))]] 3.62/2.16 [[app(nil, _x0)]] = x0 >= x0 = [[_x0]] 3.62/2.16 [[app(cons(_x0, _x1), _x2)]] = 1 + x1 + x2 >= 1 + x1 + x2 = [[cons(_x0, app(_x1, _x2))]] 3.62/2.16 [[reverse(nil)]] = 0 >= 0 = [[nil]] 3.62/2.16 [[reverse(cons(_x0, _x1))]] = 1 + x1 >= 1 + x1 = [[app(reverse(_x1), cons(_x0, nil))]] 3.62/2.16 [[shuffle(nil)]] = 0 >= 0 = [[nil]] 3.62/2.16 [[shuffle(cons(_x0, _x1))]] = 2 + 2x1 >= 1 + 2x1 = [[cons(_x0, shuffle(reverse(_x1)))]] 3.62/2.16 [[fst(p(_x0, _x1))]] = x0 >= x0 = [[_x0]] 3.62/2.16 [[#argfun-pshuffle#(p(_x0, shuffle(_x0)))]] = x0 >= x0 = [[p(_x0, shuffle(_x0))]] 3.62/2.16 [[apply2(_F0, _x1, 0)]] = x1 + F0(x1,x1) >= x1 = [[_x1]] 3.62/2.16 [[apply2(_F0, _x1, s(_x2))]] = x1 + F0(x1,x1) >= F0(x1,0) = [[_F0 _x1 s(_x2)]] 3.62/2.16 3.62/2.16 By the observations in [Kop12, Sec. 6.6], this reduction pair suffices; we may thus replace a dependency pair problem (P_1, R_1) by ({}, R_1). By the empty set processor [Kop12, Thm. 7.15] this problem may be immediately removed. 3.62/2.16 3.62/2.16 As all dependency pair problems were succesfully simplified with sound (and complete) processors until nothing remained, we conclude termination. 3.62/2.16 3.62/2.16 3.62/2.16 +++ Citations +++ 3.62/2.16 3.62/2.16 [Kop12] C. Kop. Higher Order Termination. PhD Thesis, 2012. 3.62/2.16 [Kop13] C. Kop. Static Dependency Pairs with Accessibility. Unpublished manuscript, http://cl-informatik.uibk.ac.at/users/kop/static.pdf, 2013. 3.62/2.16 [KusIsoSakBla09] K. Kusakari, Y. Isogai, M. Sakai, and F. Blanqui. Static Dependency Pair Method Based On Strong Computability for Higher-Order Rewrite Systems. In volume 92(10) of IEICE Transactions on Information and Systems. 2007--2015, 2009. 3.62/2.16 EOF