/export/starexec/sandbox2/solver/bin/starexec_run_FirstOrder /export/starexec/sandbox2/benchmark/theBenchmark.xml /export/starexec/sandbox2/output/output_files -------------------------------------------------------------------------------- YES We consider the system theBenchmark. We are asked to determine termination of the following first-order TRS. a : [] --> o b : [o * o] --> o f!62200 : [o] --> o f!62201 : [o] --> o f!622010 : [o] --> o f!62202 : [o] --> o f!62203 : [o] --> o f!62204 : [o] --> o f!62205 : [o] --> o f!62206 : [o] --> o f!62207 : [o] --> o f!62208 : [o] --> o f!62209 : [o] --> o g!62201 : [o * o] --> o g!622010 : [o * o] --> o g!62202 : [o * o] --> o g!62203 : [o * o] --> o g!62204 : [o * o] --> o g!62205 : [o * o] --> o g!62206 : [o * o] --> o g!62207 : [o * o] --> o g!62208 : [o * o] --> o g!62209 : [o * o] --> o s : [o] --> o f!62200(X) => a f!62201(X) => g!62201(X, X) g!62201(s(X), Y) => b(f!62200(Y), g!62201(X, Y)) f!62202(X) => g!62202(X, X) g!62202(s(X), Y) => b(f!62201(Y), g!62202(X, Y)) f!62203(X) => g!62203(X, X) g!62203(s(X), Y) => b(f!62202(Y), g!62203(X, Y)) f!62204(X) => g!62204(X, X) g!62204(s(X), Y) => b(f!62203(Y), g!62204(X, Y)) f!62205(X) => g!62205(X, X) g!62205(s(X), Y) => b(f!62204(Y), g!62205(X, Y)) f!62206(X) => g!62206(X, X) g!62206(s(X), Y) => b(f!62205(Y), g!62206(X, Y)) f!62207(X) => g!62207(X, X) g!62207(s(X), Y) => b(f!62206(Y), g!62207(X, Y)) f!62208(X) => g!62208(X, X) g!62208(s(X), Y) => b(f!62207(Y), g!62208(X, Y)) f!62209(X) => g!62209(X, X) g!62209(s(X), Y) => b(f!62208(Y), g!62209(X, Y)) f!622010(X) => g!622010(X, X) g!622010(s(X), Y) => b(f!62209(Y), g!622010(X, Y)) As the system is orthogonal, it is terminating if it is innermost terminating by [Gra95]. Then, by [FuhGieParSchSwi11], it suffices to prove (innermost) termination of the typed system, with sort annotations chosen to respect the rules, as follows: a : [] --> lh b : [lh * lh] --> lh f!62200 : [dh] --> lh f!62201 : [dh] --> lh f!622010 : [dh] --> lh f!62202 : [dh] --> lh f!62203 : [dh] --> lh f!62204 : [dh] --> lh f!62205 : [dh] --> lh f!62206 : [dh] --> lh f!62207 : [dh] --> lh f!62208 : [dh] --> lh f!62209 : [dh] --> lh g!62201 : [dh * dh] --> lh g!622010 : [dh * dh] --> lh g!62202 : [dh * dh] --> lh g!62203 : [dh * dh] --> lh g!62204 : [dh * dh] --> lh g!62205 : [dh * dh] --> lh g!62206 : [dh * dh] --> lh g!62207 : [dh * dh] --> lh g!62208 : [dh * dh] --> lh g!62209 : [dh * dh] --> lh s : [dh] --> dh We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a f!62201(X) >? g!62201(X, X) g!62201(s(X), Y) >? b(f!62200(Y), g!62201(X, Y)) f!62202(X) >? g!62202(X, X) g!62202(s(X), Y) >? b(f!62201(Y), g!62202(X, Y)) f!62203(X) >? g!62203(X, X) g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) f!62204(X) >? g!62204(X, X) g!62204(s(X), Y) >? b(f!62203(Y), g!62204(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62206(X) >? g!62206(X, X) g!62206(s(X), Y) >? b(f!62205(Y), g!62206(X, Y)) f!62207(X) >? g!62207(X, X) g!62207(s(X), Y) >? b(f!62206(Y), g!62207(X, Y)) f!62208(X) >? g!62208(X, X) g!62208(s(X), Y) >? b(f!62207(Y), g!62208(X, Y)) f!62209(X) >? g!62209(X, X) g!62209(s(X), Y) >? b(f!62208(Y), g!62209(X, Y)) f!622010(X) >? g!622010(X, X) g!622010(s(X), Y) >? b(f!62209(Y), g!622010(X, Y)) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[g!62201(x_1, x_2)]] = g!62201(x_2, x_1) We choose Lex = {g!62201} and Mul = {b, f!62201, f!622010, f!62202, f!62203, f!62204, f!62205, f!62206, f!62207, f!62208, f!62209, g!622010, g!62202, g!62203, g!62204, g!62205, g!62206, g!62207, g!62208, g!62209, s}, and the following precedence: f!622010 > g!622010 > f!62209 > g!62209 > f!62208 > f!62207 = g!62208 > g!62207 > f!62206 > g!62206 > f!62205 > g!62205 > f!62204 > g!62204 > f!62203 > f!62202 = g!62203 > s > f!62201 = g!62202 > g!62201 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ f!62201(X) > g!62201(X, X) g!62201(s(X), Y) >= b(Y, g!62201(X, Y)) f!62202(X) > g!62202(X, X) g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) f!62203(X) > g!62203(X, X) g!62203(s(X), Y) >= b(f!62202(Y), g!62203(X, Y)) f!62204(X) > g!62204(X, X) g!62204(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) f!62206(X) >= g!62206(X, X) g!62206(s(X), Y) > b(f!62205(Y), g!62206(X, Y)) f!62207(X) > g!62207(X, X) g!62207(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) f!62208(X) >= g!62208(X, X) g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) f!62209(X) > g!62209(X, X) g!62209(s(X), Y) > b(f!62208(Y), g!62209(X, Y)) f!622010(X) >= g!622010(X, X) g!622010(s(X), Y) > b(f!62209(Y), g!622010(X, Y)) With these choices, we have: 1] X >= _|_ by (Bot) 2] f!62201(X) > g!62201(X, X) because [3], by definition 3] f!62201*(X) >= g!62201(X, X) because f!62201 > g!62201, [4] and [4], by (Copy) 4] f!62201*(X) >= X because [5], by (Select) 5] X >= X by (Meta) 6] g!62201(s(X), Y) >= b(Y, g!62201(X, Y)) because [7], by (Star) 7] g!62201*(s(X), Y) >= b(Y, g!62201(X, Y)) because g!62201 > b, [8] and [10], by (Copy) 8] g!62201*(s(X), Y) >= Y because [9], by (Select) 9] Y >= Y by (Meta) 10] g!62201*(s(X), Y) >= g!62201(X, Y) because [11], [13], [14] and [8], by (Stat) 11] s(X) > X because [12], by definition 12] s*(X) >= X because [5], by (Select) 13] Y >= Y by (Meta) 14] g!62201*(s(X), Y) >= X because [15], by (Select) 15] s(X) >= X because [12], by (Star) 16] f!62202(X) > g!62202(X, X) because [17], by definition 17] f!62202*(X) >= g!62202(X, X) because f!62202 > g!62202, [18] and [18], by (Copy) 18] f!62202*(X) >= X because [5], by (Select) 19] g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because [20], by (Star) 20] g!62202*(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because g!62202 > b, [21] and [22], by (Copy) 21] g!62202*(s(X), Y) >= f!62201(Y) because g!62202 = f!62201, g!62202 in Mul and [13], by (Stat) 22] g!62202*(s(X), Y) >= g!62202(X, Y) because g!62202 in Mul, [11] and [13], by (Stat) 23] f!62203(X) > g!62203(X, X) because [24], by definition 24] f!62203*(X) >= g!62203(X, X) because f!62203 > g!62203, [25] and [25], by (Copy) 25] f!62203*(X) >= X because [5], by (Select) 26] g!62203(s(X), Y) >= b(f!62202(Y), g!62203(X, Y)) because [27], by (Star) 27] g!62203*(s(X), Y) >= b(f!62202(Y), g!62203(X, Y)) because g!62203 > b, [28] and [29], by (Copy) 28] g!62203*(s(X), Y) >= f!62202(Y) because g!62203 = f!62202, g!62203 in Mul and [13], by (Stat) 29] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [11] and [13], by (Stat) 30] f!62204(X) > g!62204(X, X) because [31], by definition 31] f!62204*(X) >= g!62204(X, X) because f!62204 > g!62204, [32] and [32], by (Copy) 32] f!62204*(X) >= X because [5], by (Select) 33] g!62204(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) because [34], by (Star) 34] g!62204*(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) because g!62204 > b, [35] and [37], by (Copy) 35] g!62204*(s(X), Y) >= f!62203(Y) because g!62204 > f!62203 and [36], by (Copy) 36] g!62204*(s(X), Y) >= Y because [13], by (Select) 37] g!62204*(s(X), Y) >= g!62204(X, Y) because g!62204 in Mul, [11] and [13], by (Stat) 38] f!62205(X) >= g!62205(X, X) because [39], by (Star) 39] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [40] and [40], by (Copy) 40] f!62205*(X) >= X because [5], by (Select) 41] g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because [42], by (Star) 42] g!62205*(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because g!62205 > b, [43] and [45], by (Copy) 43] g!62205*(s(X), Y) >= f!62204(Y) because g!62205 > f!62204 and [44], by (Copy) 44] g!62205*(s(X), Y) >= Y because [13], by (Select) 45] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [11] and [13], by (Stat) 46] f!62206(X) >= g!62206(X, X) because [47], by (Star) 47] f!62206*(X) >= g!62206(X, X) because f!62206 > g!62206, [48] and [48], by (Copy) 48] f!62206*(X) >= X because [5], by (Select) 49] g!62206(s(X), Y) > b(f!62205(Y), g!62206(X, Y)) because [50], by definition 50] g!62206*(s(X), Y) >= b(f!62205(Y), g!62206(X, Y)) because g!62206 > b, [51] and [53], by (Copy) 51] g!62206*(s(X), Y) >= f!62205(Y) because g!62206 > f!62205 and [52], by (Copy) 52] g!62206*(s(X), Y) >= Y because [13], by (Select) 53] g!62206*(s(X), Y) >= g!62206(X, Y) because g!62206 in Mul, [11] and [13], by (Stat) 54] f!62207(X) > g!62207(X, X) because [55], by definition 55] f!62207*(X) >= g!62207(X, X) because f!62207 > g!62207, [56] and [56], by (Copy) 56] f!62207*(X) >= X because [5], by (Select) 57] g!62207(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) because [58], by (Star) 58] g!62207*(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) because g!62207 > b, [59] and [61], by (Copy) 59] g!62207*(s(X), Y) >= f!62206(Y) because g!62207 > f!62206 and [60], by (Copy) 60] g!62207*(s(X), Y) >= Y because [13], by (Select) 61] g!62207*(s(X), Y) >= g!62207(X, Y) because g!62207 in Mul, [11] and [13], by (Stat) 62] f!62208(X) >= g!62208(X, X) because [63], by (Star) 63] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [64] and [64], by (Copy) 64] f!62208*(X) >= X because [5], by (Select) 65] g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because [66], by (Star) 66] g!62208*(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because g!62208 > b, [67] and [68], by (Copy) 67] g!62208*(s(X), Y) >= f!62207(Y) because g!62208 = f!62207, g!62208 in Mul and [13], by (Stat) 68] g!62208*(s(X), Y) >= g!62208(X, Y) because g!62208 in Mul, [11] and [13], by (Stat) 69] f!62209(X) > g!62209(X, X) because [70], by definition 70] f!62209*(X) >= g!62209(X, X) because f!62209 > g!62209, [71] and [71], by (Copy) 71] f!62209*(X) >= X because [5], by (Select) 72] g!62209(s(X), Y) > b(f!62208(Y), g!62209(X, Y)) because [73], by definition 73] g!62209*(s(X), Y) >= b(f!62208(Y), g!62209(X, Y)) because g!62209 > b, [74] and [76], by (Copy) 74] g!62209*(s(X), Y) >= f!62208(Y) because g!62209 > f!62208 and [75], by (Copy) 75] g!62209*(s(X), Y) >= Y because [13], by (Select) 76] g!62209*(s(X), Y) >= g!62209(X, Y) because g!62209 in Mul, [11] and [13], by (Stat) 77] f!622010(X) >= g!622010(X, X) because [78], by (Star) 78] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [79] and [79], by (Copy) 79] f!622010*(X) >= X because [5], by (Select) 80] g!622010(s(X), Y) > b(f!62209(Y), g!622010(X, Y)) because [81], by definition 81] g!622010*(s(X), Y) >= b(f!62209(Y), g!622010(X, Y)) because g!622010 > b, [82] and [84], by (Copy) 82] g!622010*(s(X), Y) >= f!62209(Y) because g!622010 > f!62209 and [83], by (Copy) 83] g!622010*(s(X), Y) >= Y because [13], by (Select) 84] g!622010*(s(X), Y) >= g!622010(X, Y) because g!622010 in Mul, [11] and [13], by (Stat) We can thus remove the following rules: f!62201(X) => g!62201(X, X) f!62202(X) => g!62202(X, X) f!62203(X) => g!62203(X, X) f!62204(X) => g!62204(X, X) g!62206(s(X), Y) => b(f!62205(Y), g!62206(X, Y)) f!62207(X) => g!62207(X, X) f!62209(X) => g!62209(X, X) g!62209(s(X), Y) => b(f!62208(Y), g!62209(X, Y)) g!622010(s(X), Y) => b(f!62209(Y), g!622010(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62201(s(X), Y) >? b(f!62200(Y), g!62201(X, Y)) g!62202(s(X), Y) >? b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) g!62204(s(X), Y) >? b(f!62203(Y), g!62204(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62206(X) >? g!62206(X, X) g!62207(s(X), Y) >? b(f!62206(Y), g!62207(X, Y)) f!62208(X) >? g!62208(X, X) g!62208(s(X), Y) >? b(f!62207(Y), g!62208(X, Y)) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[f!62202(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!62201, f!622010, f!62203, f!62204, f!62205, f!62206, f!62207, f!62208, g!62201, g!622010, g!62202, g!62203, g!62204, g!62205, g!62206, g!62207, g!62208, s}, and the following precedence: g!62204 > g!62202 > f!622010 > g!62207 > f!62205 > f!62203 > g!62205 > f!62201 > f!62204 > f!62206 > f!62208 > g!62206 > f!62207 = g!62208 > g!622010 > g!62201 > g!62203 > s > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62201(s(X), Y) > b(Y, g!62201(X, Y)) g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) g!62204(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) f!62206(X) > g!62206(X, X) g!62207(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) f!62208(X) >= g!62208(X, X) g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62201(s(X), Y) > b(Y, g!62201(X, Y)) because [3], by definition 3] g!62201*(s(X), Y) >= b(Y, g!62201(X, Y)) because g!62201 > b, [4] and [6], by (Copy) 4] g!62201*(s(X), Y) >= Y because [5], by (Select) 5] Y >= Y by (Meta) 6] g!62201*(s(X), Y) >= g!62201(X, Y) because g!62201 in Mul, [7] and [10], by (Stat) 7] s(X) > X because [8], by definition 8] s*(X) >= X because [9], by (Select) 9] X >= X by (Meta) 10] Y >= Y by (Meta) 11] g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because [12], by (Star) 12] g!62202*(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because g!62202 > b, [13] and [15], by (Copy) 13] g!62202*(s(X), Y) >= f!62201(Y) because g!62202 > f!62201 and [14], by (Copy) 14] g!62202*(s(X), Y) >= Y because [10], by (Select) 15] g!62202*(s(X), Y) >= g!62202(X, Y) because g!62202 in Mul, [7] and [10], by (Stat) 16] g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) because [17], by (Star) 17] g!62203*(s(X), Y) >= b(Y, g!62203(X, Y)) because g!62203 > b, [18] and [19], by (Copy) 18] g!62203*(s(X), Y) >= Y because [10], by (Select) 19] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [7] and [10], by (Stat) 20] g!62204(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) because [21], by (Star) 21] g!62204*(s(X), Y) >= b(f!62203(Y), g!62204(X, Y)) because g!62204 > b, [22] and [24], by (Copy) 22] g!62204*(s(X), Y) >= f!62203(Y) because g!62204 > f!62203 and [23], by (Copy) 23] g!62204*(s(X), Y) >= Y because [10], by (Select) 24] g!62204*(s(X), Y) >= g!62204(X, Y) because g!62204 in Mul, [7] and [10], by (Stat) 25] f!62205(X) >= g!62205(X, X) because [26], by (Star) 26] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [27] and [27], by (Copy) 27] f!62205*(X) >= X because [9], by (Select) 28] g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because [29], by (Star) 29] g!62205*(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because g!62205 > b, [30] and [32], by (Copy) 30] g!62205*(s(X), Y) >= f!62204(Y) because g!62205 > f!62204 and [31], by (Copy) 31] g!62205*(s(X), Y) >= Y because [10], by (Select) 32] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [7] and [10], by (Stat) 33] f!62206(X) > g!62206(X, X) because [34], by definition 34] f!62206*(X) >= g!62206(X, X) because f!62206 > g!62206, [35] and [35], by (Copy) 35] f!62206*(X) >= X because [9], by (Select) 36] g!62207(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) because [37], by (Star) 37] g!62207*(s(X), Y) >= b(f!62206(Y), g!62207(X, Y)) because g!62207 > b, [38] and [40], by (Copy) 38] g!62207*(s(X), Y) >= f!62206(Y) because g!62207 > f!62206 and [39], by (Copy) 39] g!62207*(s(X), Y) >= Y because [10], by (Select) 40] g!62207*(s(X), Y) >= g!62207(X, Y) because g!62207 in Mul, [7] and [10], by (Stat) 41] f!62208(X) >= g!62208(X, X) because [42], by (Star) 42] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [43] and [43], by (Copy) 43] f!62208*(X) >= X because [9], by (Select) 44] g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because [45], by (Star) 45] g!62208*(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because g!62208 > b, [46] and [47], by (Copy) 46] g!62208*(s(X), Y) >= f!62207(Y) because g!62208 = f!62207, g!62208 in Mul and [10], by (Stat) 47] g!62208*(s(X), Y) >= g!62208(X, Y) because g!62208 in Mul, [7] and [10], by (Stat) 48] f!622010(X) >= g!622010(X, X) because [49], by (Star) 49] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [50] and [50], by (Copy) 50] f!622010*(X) >= X because [9], by (Select) We can thus remove the following rules: g!62201(s(X), Y) => b(f!62200(Y), g!62201(X, Y)) f!62206(X) => g!62206(X, X) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62202(s(X), Y) >? b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) g!62204(s(X), Y) >? b(f!62203(Y), g!62204(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) g!62207(s(X), Y) >? b(f!62206(Y), g!62207(X, Y)) f!62208(X) >? g!62208(X, X) g!62208(s(X), Y) >? b(f!62207(Y), g!62208(X, Y)) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[f!62202(x_1)]] = x_1 [[f!62203(x_1)]] = x_1 [[f!62204(x_1)]] = x_1 [[f!62206(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!62201, f!622010, f!62205, f!62207, f!62208, g!622010, g!62202, g!62203, g!62204, g!62205, g!62207, g!62208, s}, and the following precedence: f!622010 > s > g!62207 > f!62208 > g!62208 > f!62201 = g!62202 > g!62204 > g!62203 > g!622010 > f!62205 > g!62205 > f!62207 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) g!62204(s(X), Y) > b(Y, g!62204(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) g!62207(s(X), Y) > b(Y, g!62207(X, Y)) f!62208(X) >= g!62208(X, X) g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62202(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because [3], by (Star) 3] g!62202*(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because g!62202 > b, [4] and [6], by (Copy) 4] g!62202*(s(X), Y) >= f!62201(Y) because g!62202 = f!62201, g!62202 in Mul and [5], by (Stat) 5] Y >= Y by (Meta) 6] g!62202*(s(X), Y) >= g!62202(X, Y) because g!62202 in Mul, [7] and [5], by (Stat) 7] s(X) > X because [8], by definition 8] s*(X) >= X because [9], by (Select) 9] X >= X by (Meta) 10] g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) because [11], by (Star) 11] g!62203*(s(X), Y) >= b(Y, g!62203(X, Y)) because g!62203 > b, [12] and [13], by (Copy) 12] g!62203*(s(X), Y) >= Y because [5], by (Select) 13] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [7] and [5], by (Stat) 14] g!62204(s(X), Y) > b(Y, g!62204(X, Y)) because [15], by definition 15] g!62204*(s(X), Y) >= b(Y, g!62204(X, Y)) because g!62204 > b, [16] and [17], by (Copy) 16] g!62204*(s(X), Y) >= Y because [5], by (Select) 17] g!62204*(s(X), Y) >= g!62204(X, Y) because g!62204 in Mul, [7] and [5], by (Stat) 18] f!62205(X) >= g!62205(X, X) because [19], by (Star) 19] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [20] and [20], by (Copy) 20] f!62205*(X) >= X because [9], by (Select) 21] g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) because [22], by (Star) 22] g!62205*(s(X), Y) >= b(Y, g!62205(X, Y)) because g!62205 > b, [23] and [24], by (Copy) 23] g!62205*(s(X), Y) >= Y because [5], by (Select) 24] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [7] and [5], by (Stat) 25] g!62207(s(X), Y) > b(Y, g!62207(X, Y)) because [26], by definition 26] g!62207*(s(X), Y) >= b(Y, g!62207(X, Y)) because g!62207 > b, [27] and [28], by (Copy) 27] g!62207*(s(X), Y) >= Y because [5], by (Select) 28] g!62207*(s(X), Y) >= g!62207(X, Y) because g!62207 in Mul, [7] and [5], by (Stat) 29] f!62208(X) >= g!62208(X, X) because [30], by (Star) 30] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [31] and [31], by (Copy) 31] f!62208*(X) >= X because [9], by (Select) 32] g!62208(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because [33], by (Star) 33] g!62208*(s(X), Y) >= b(f!62207(Y), g!62208(X, Y)) because g!62208 > b, [34] and [36], by (Copy) 34] g!62208*(s(X), Y) >= f!62207(Y) because g!62208 > f!62207 and [35], by (Copy) 35] g!62208*(s(X), Y) >= Y because [5], by (Select) 36] g!62208*(s(X), Y) >= g!62208(X, Y) because g!62208 in Mul, [7] and [5], by (Stat) 37] f!622010(X) >= g!622010(X, X) because [38], by (Star) 38] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [39] and [39], by (Copy) 39] f!622010*(X) >= X because [9], by (Select) We can thus remove the following rules: g!62204(s(X), Y) => b(f!62203(Y), g!62204(X, Y)) g!62207(s(X), Y) => b(f!62206(Y), g!62207(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62202(s(X), Y) >? b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62208(X) >? g!62208(X, X) g!62208(s(X), Y) >? b(f!62207(Y), g!62208(X, Y)) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[f!62202(x_1)]] = x_1 [[f!62204(x_1)]] = x_1 [[f!62207(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!62201, f!622010, f!62205, f!62208, g!622010, g!62202, g!62203, g!62205, g!62208, s}, and the following precedence: f!62208 > s > f!62201 = g!62202 > f!622010 > g!622010 > f!62205 > g!62205 > g!62208 > g!62203 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62202(s(X), Y) > b(f!62201(Y), g!62202(X, Y)) g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) f!62208(X) >= g!62208(X, X) g!62208(s(X), Y) >= b(Y, g!62208(X, Y)) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62202(s(X), Y) > b(f!62201(Y), g!62202(X, Y)) because [3], by definition 3] g!62202*(s(X), Y) >= b(f!62201(Y), g!62202(X, Y)) because g!62202 > b, [4] and [6], by (Copy) 4] g!62202*(s(X), Y) >= f!62201(Y) because g!62202 = f!62201, g!62202 in Mul and [5], by (Stat) 5] Y >= Y by (Meta) 6] g!62202*(s(X), Y) >= g!62202(X, Y) because g!62202 in Mul, [7] and [5], by (Stat) 7] s(X) > X because [8], by definition 8] s*(X) >= X because [9], by (Select) 9] X >= X by (Meta) 10] g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) because [11], by (Star) 11] g!62203*(s(X), Y) >= b(Y, g!62203(X, Y)) because g!62203 > b, [12] and [13], by (Copy) 12] g!62203*(s(X), Y) >= Y because [5], by (Select) 13] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [7] and [5], by (Stat) 14] f!62205(X) >= g!62205(X, X) because [15], by (Star) 15] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [16] and [16], by (Copy) 16] f!62205*(X) >= X because [9], by (Select) 17] g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) because [18], by (Star) 18] g!62205*(s(X), Y) >= b(Y, g!62205(X, Y)) because g!62205 > b, [19] and [20], by (Copy) 19] g!62205*(s(X), Y) >= Y because [5], by (Select) 20] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [7] and [5], by (Stat) 21] f!62208(X) >= g!62208(X, X) because [22], by (Star) 22] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [23] and [23], by (Copy) 23] f!62208*(X) >= X because [9], by (Select) 24] g!62208(s(X), Y) >= b(Y, g!62208(X, Y)) because [25], by (Star) 25] g!62208*(s(X), Y) >= b(Y, g!62208(X, Y)) because g!62208 > b, [26] and [27], by (Copy) 26] g!62208*(s(X), Y) >= Y because [5], by (Select) 27] g!62208*(s(X), Y) >= g!62208(X, Y) because g!62208 in Mul, [7] and [5], by (Stat) 28] f!622010(X) >= g!622010(X, X) because [29], by (Star) 29] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [30] and [30], by (Copy) 30] f!622010*(X) >= X because [9], by (Select) We can thus remove the following rules: g!62202(s(X), Y) => b(f!62201(Y), g!62202(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62208(X) >? g!62208(X, X) g!62208(s(X), Y) >? b(f!62207(Y), g!62208(X, Y)) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[f!62202(x_1)]] = x_1 [[f!62204(x_1)]] = x_1 [[f!62207(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!622010, f!62205, f!62208, g!622010, g!62203, g!62205, g!62208, s}, and the following precedence: f!62208 > g!62208 > s > g!62203 > f!622010 > g!622010 > f!62205 > g!62205 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) f!62208(X) >= g!62208(X, X) g!62208(s(X), Y) > b(Y, g!62208(X, Y)) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62203(s(X), Y) >= b(Y, g!62203(X, Y)) because [3], by (Star) 3] g!62203*(s(X), Y) >= b(Y, g!62203(X, Y)) because g!62203 > b, [4] and [6], by (Copy) 4] g!62203*(s(X), Y) >= Y because [5], by (Select) 5] Y >= Y by (Meta) 6] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [7] and [10], by (Stat) 7] s(X) > X because [8], by definition 8] s*(X) >= X because [9], by (Select) 9] X >= X by (Meta) 10] Y >= Y by (Meta) 11] f!62205(X) >= g!62205(X, X) because [12], by (Star) 12] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [13] and [13], by (Copy) 13] f!62205*(X) >= X because [9], by (Select) 14] g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) because [15], by (Star) 15] g!62205*(s(X), Y) >= b(Y, g!62205(X, Y)) because g!62205 > b, [16] and [17], by (Copy) 16] g!62205*(s(X), Y) >= Y because [10], by (Select) 17] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [7] and [10], by (Stat) 18] f!62208(X) >= g!62208(X, X) because [19], by (Star) 19] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [20] and [20], by (Copy) 20] f!62208*(X) >= X because [9], by (Select) 21] g!62208(s(X), Y) > b(Y, g!62208(X, Y)) because [22], by definition 22] g!62208*(s(X), Y) >= b(Y, g!62208(X, Y)) because g!62208 > b, [23] and [24], by (Copy) 23] g!62208*(s(X), Y) >= Y because [10], by (Select) 24] g!62208*(s(X), Y) >= g!62208(X, Y) because g!62208 in Mul, [7] and [10], by (Stat) 25] f!622010(X) >= g!622010(X, X) because [26], by (Star) 26] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [27] and [27], by (Copy) 27] f!622010*(X) >= X because [9], by (Select) We can thus remove the following rules: g!62208(s(X), Y) => b(f!62207(Y), g!62208(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62203(s(X), Y) >? b(f!62202(Y), g!62203(X, Y)) f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62208(X) >? g!62208(X, X) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 [[f!62202(x_1)]] = x_1 [[f!62204(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!622010, f!62205, f!62208, g!622010, g!62203, g!62205, g!62208, s}, and the following precedence: g!62203 > f!622010 > g!622010 > s > f!62208 > g!62208 > f!62205 > g!62205 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62203(s(X), Y) > b(Y, g!62203(X, Y)) f!62205(X) >= g!62205(X, X) g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) f!62208(X) >= g!62208(X, X) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62203(s(X), Y) > b(Y, g!62203(X, Y)) because [3], by definition 3] g!62203*(s(X), Y) >= b(Y, g!62203(X, Y)) because g!62203 > b, [4] and [6], by (Copy) 4] g!62203*(s(X), Y) >= Y because [5], by (Select) 5] Y >= Y by (Meta) 6] g!62203*(s(X), Y) >= g!62203(X, Y) because g!62203 in Mul, [7] and [10], by (Stat) 7] s(X) > X because [8], by definition 8] s*(X) >= X because [9], by (Select) 9] X >= X by (Meta) 10] Y >= Y by (Meta) 11] f!62205(X) >= g!62205(X, X) because [12], by (Star) 12] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [13] and [13], by (Copy) 13] f!62205*(X) >= X because [9], by (Select) 14] g!62205(s(X), Y) >= b(Y, g!62205(X, Y)) because [15], by (Star) 15] g!62205*(s(X), Y) >= b(Y, g!62205(X, Y)) because g!62205 > b, [16] and [17], by (Copy) 16] g!62205*(s(X), Y) >= Y because [10], by (Select) 17] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [7] and [10], by (Stat) 18] f!62208(X) >= g!62208(X, X) because [19], by (Star) 19] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [20] and [20], by (Copy) 20] f!62208*(X) >= X because [9], by (Select) 21] f!622010(X) >= g!622010(X, X) because [22], by (Star) 22] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [23] and [23], by (Copy) 23] f!622010*(X) >= X because [9], by (Select) We can thus remove the following rules: g!62203(s(X), Y) => b(f!62202(Y), g!62203(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a f!62205(X) >? g!62205(X, X) g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62208(X) >? g!62208(X, X) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!622010, f!62204, f!62205, f!62208, g!622010, g!62205, g!62208, s}, and the following precedence: f!622010 > f!62208 > g!622010 > g!62208 > s > f!62205 > g!62205 > f!62204 > b Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ f!62205(X) > g!62205(X, X) g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) f!62208(X) >= g!62208(X, X) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] f!62205(X) > g!62205(X, X) because [3], by definition 3] f!62205*(X) >= g!62205(X, X) because f!62205 > g!62205, [4] and [4], by (Copy) 4] f!62205*(X) >= X because [5], by (Select) 5] X >= X by (Meta) 6] g!62205(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because [7], by (Star) 7] g!62205*(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because g!62205 > b, [8] and [11], by (Copy) 8] g!62205*(s(X), Y) >= f!62204(Y) because g!62205 > f!62204 and [9], by (Copy) 9] g!62205*(s(X), Y) >= Y because [10], by (Select) 10] Y >= Y by (Meta) 11] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [12] and [14], by (Stat) 12] s(X) > X because [13], by definition 13] s*(X) >= X because [5], by (Select) 14] Y >= Y by (Meta) 15] f!62208(X) >= g!62208(X, X) because [16], by (Star) 16] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [17] and [17], by (Copy) 17] f!62208*(X) >= X because [5], by (Select) 18] f!622010(X) >= g!622010(X, X) because [19], by (Star) 19] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [20] and [20], by (Copy) 20] f!622010*(X) >= X because [5], by (Select) We can thus remove the following rules: f!62205(X) => g!62205(X, X) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a g!62205(s(X), Y) >? b(f!62204(Y), g!62205(X, Y)) f!62208(X) >? g!62208(X, X) f!622010(X) >? g!622010(X, X) about to try horpo We use a recursive path ordering as defined in [Kop12, Chapter 5]. Argument functions: [[a]] = _|_ [[f!62200(x_1)]] = x_1 We choose Lex = {} and Mul = {b, f!622010, f!62204, f!62208, g!622010, g!62205, g!62208, s}, and the following precedence: g!62205 > s > f!62208 > f!62204 > g!62208 > b > f!622010 > g!622010 Taking the argument function into account, and fixing the greater / greater equal choices, the constraints can be denoted as follows: X >= _|_ g!62205(s(X), Y) > b(f!62204(Y), g!62205(X, Y)) f!62208(X) >= g!62208(X, X) f!622010(X) >= g!622010(X, X) With these choices, we have: 1] X >= _|_ by (Bot) 2] g!62205(s(X), Y) > b(f!62204(Y), g!62205(X, Y)) because [3], by definition 3] g!62205*(s(X), Y) >= b(f!62204(Y), g!62205(X, Y)) because g!62205 > b, [4] and [7], by (Copy) 4] g!62205*(s(X), Y) >= f!62204(Y) because g!62205 > f!62204 and [5], by (Copy) 5] g!62205*(s(X), Y) >= Y because [6], by (Select) 6] Y >= Y by (Meta) 7] g!62205*(s(X), Y) >= g!62205(X, Y) because g!62205 in Mul, [8] and [11], by (Stat) 8] s(X) > X because [9], by definition 9] s*(X) >= X because [10], by (Select) 10] X >= X by (Meta) 11] Y >= Y by (Meta) 12] f!62208(X) >= g!62208(X, X) because [13], by (Star) 13] f!62208*(X) >= g!62208(X, X) because f!62208 > g!62208, [14] and [14], by (Copy) 14] f!62208*(X) >= X because [10], by (Select) 15] f!622010(X) >= g!622010(X, X) because [16], by (Star) 16] f!622010*(X) >= g!622010(X, X) because f!622010 > g!622010, [17] and [17], by (Copy) 17] f!622010*(X) >= X because [10], by (Select) We can thus remove the following rules: g!62205(s(X), Y) => b(f!62204(Y), g!62205(X, Y)) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): f!62200(X) >? a f!62208(X) >? g!62208(X, X) f!622010(X) >? g!622010(X, X) We orient these requirements with a polynomial interpretation in the natural numbers. The following interpretation satisfies the requirements: a = 0 f!62200 = \y0.3 + y0 f!622010 = \y0.3 + 3y0 f!62208 = \y0.3 + 3y0 g!622010 = \y0y1.y0 + y1 g!62208 = \y0y1.y0 + y1 Using this interpretation, the requirements translate to: [[f!62200(_x0)]] = 3 + x0 > 0 = [[a]] [[f!62208(_x0)]] = 3 + 3x0 > 2x0 = [[g!62208(_x0, _x0)]] [[f!622010(_x0)]] = 3 + 3x0 > 2x0 = [[g!622010(_x0, _x0)]] We can thus remove the following rules: f!62200(X) => a f!62208(X) => g!62208(X, X) f!622010(X) => g!622010(X, X) All rules were succesfully removed. Thus, termination of the original system has been reduced to termination of the beta-rule, which is well-known to hold. +++ Citations +++ [FuhGieParSchSwi11] C. Fuhs, J. Giesl, M. Parting, P. Schneider-Kamp, and S. Swiderski. Proving Termination by Dependency Pairs and Inductive Theorem Proving. In volume 47(2) of Journal of Automated Reasoning. 133--160, 2011. [Gra95] B. Gramlich. Abstract Relations Between Restricted Termination and Confluence Properties of Rewrite Systems. In volume 24(1-2) of Fundamentae Informaticae. 3--23, 1995. [Kop12] C. Kop. Higher Order Termination. PhD Thesis, 2012.