YES We show the termination of the TRS R: app(f(),app(app(cons(),nil()),y)) -> y app(f(),app(app(cons(),app(f(),app(app(cons(),nil()),y))),z)) -> app(app(app(copy(),n()),y),z) app(app(app(copy(),|0|()),y),z) -> app(f(),z) app(app(app(copy(),app(s(),x)),y),z) -> app(app(app(copy(),x),y),app(app(cons(),app(f(),y)),z)) app(app(map(),|fun|),nil()) -> nil() app(app(map(),|fun|),app(app(cons(),x),xs)) -> app(app(cons(),app(|fun|,x)),app(app(map(),|fun|),xs)) app(app(filter(),|fun|),nil()) -> nil() app(app(filter(),|fun|),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(|fun|,x)),|fun|),x),xs) app(app(app(app(filter2(),true()),|fun|),x),xs) -> app(app(cons(),x),app(app(filter(),|fun|),xs)) app(app(app(app(filter2(),false()),|fun|),x),xs) -> app(app(filter(),|fun|),xs) Instead we prove termination of the uncurried system: app(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,y) app(copy_0(),y) -> copy_1(y) app(copy_1(x1),y) -> copy_2(x1,y) app(copy_2(x1,x2),y) -> copy_3(x1,x2,y) app(f_0(),y) -> f_1(y) app(filter_0(),y) -> filter_1(y) app(filter_1(x1),y) -> filter_2(x1,y) app(filter2_0(),y) -> filter2_1(y) app(filter2_1(x1),y) -> filter2_2(x1,y) app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) app(s_0(),y) -> s_1(y) f_1(cons_2(nil_0(),y)) -> y f_1(cons_2(f_1(cons_2(nil_0(),y)),z)) -> copy_3(n_0(),y,z) copy_3(|0|_0(),y,z) -> f_1(z) copy_3(s_1(x),y,z) -> copy_3(x,y,cons_2(f_1(y),z)) map_2(|fun|,nil_0()) -> nil_0() map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) filter_2(|fun|,nil_0()) -> nil_0() filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(copy_2(x1,x2),y) -> copy_3#(x1,x2,y) p2: app#(f_0(),y) -> f_1#(y) p3: app#(filter_1(x1),y) -> filter_2#(x1,y) p4: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p5: app#(map_1(x1),y) -> map_2#(x1,y) p6: f_1#(cons_2(f_1(cons_2(nil_0(),y)),z)) -> copy_3#(n_0(),y,z) p7: copy_3#(|0|_0(),y,z) -> f_1#(z) p8: copy_3#(s_1(x),y,z) -> copy_3#(x,y,cons_2(f_1(y),z)) p9: copy_3#(s_1(x),y,z) -> f_1#(y) p10: map_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p11: map_2#(|fun|,cons_2(x,xs)) -> map_2#(|fun|,xs) p12: filter_2#(|fun|,cons_2(x,xs)) -> filter2_4#(app(|fun|,x),|fun|,x,xs) p13: filter_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p14: filter2_4#(true_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) p15: filter2_4#(false_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(copy_0(),y) -> copy_1(y) r4: app(copy_1(x1),y) -> copy_2(x1,y) r5: app(copy_2(x1,x2),y) -> copy_3(x1,x2,y) r6: app(f_0(),y) -> f_1(y) r7: app(filter_0(),y) -> filter_1(y) r8: app(filter_1(x1),y) -> filter_2(x1,y) r9: app(filter2_0(),y) -> filter2_1(y) r10: app(filter2_1(x1),y) -> filter2_2(x1,y) r11: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r12: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r13: app(map_0(),y) -> map_1(y) r14: app(map_1(x1),y) -> map_2(x1,y) r15: app(s_0(),y) -> s_1(y) r16: f_1(cons_2(nil_0(),y)) -> y r17: f_1(cons_2(f_1(cons_2(nil_0(),y)),z)) -> copy_3(n_0(),y,z) r18: copy_3(|0|_0(),y,z) -> f_1(z) r19: copy_3(s_1(x),y,z) -> copy_3(x,y,cons_2(f_1(y),z)) r20: map_2(|fun|,nil_0()) -> nil_0() r21: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r22: filter_2(|fun|,nil_0()) -> nil_0() r23: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r24: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r25: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The estimated dependency graph contains the following SCCs: {p3, p4, p5, p10, p11, p12, p13, p14, p15} {p8} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p2: app#(map_1(x1),y) -> map_2#(x1,y) p3: map_2#(|fun|,cons_2(x,xs)) -> map_2#(|fun|,xs) p4: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p5: filter2_4#(false_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) p6: filter_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p7: app#(filter_1(x1),y) -> filter_2#(x1,y) p8: filter_2#(|fun|,cons_2(x,xs)) -> filter2_4#(app(|fun|,x),|fun|,x,xs) p9: filter2_4#(true_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(copy_0(),y) -> copy_1(y) r4: app(copy_1(x1),y) -> copy_2(x1,y) r5: app(copy_2(x1,x2),y) -> copy_3(x1,x2,y) r6: app(f_0(),y) -> f_1(y) r7: app(filter_0(),y) -> filter_1(y) r8: app(filter_1(x1),y) -> filter_2(x1,y) r9: app(filter2_0(),y) -> filter2_1(y) r10: app(filter2_1(x1),y) -> filter2_2(x1,y) r11: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r12: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r13: app(map_0(),y) -> map_1(y) r14: app(map_1(x1),y) -> map_2(x1,y) r15: app(s_0(),y) -> s_1(y) r16: f_1(cons_2(nil_0(),y)) -> y r17: f_1(cons_2(f_1(cons_2(nil_0(),y)),z)) -> copy_3(n_0(),y,z) r18: copy_3(|0|_0(),y,z) -> f_1(z) r19: copy_3(s_1(x),y,z) -> copy_3(x,y,cons_2(f_1(y),z)) r20: map_2(|fun|,nil_0()) -> nil_0() r21: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r22: filter_2(|fun|,nil_0()) -> nil_0() r23: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r24: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r25: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r16 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: map_2#_A(x1,x2) = x1 cons_2_A(x1,x2) = x1 + x2 + 11 app#_A(x1,x2) = x1 map_1_A(x1) = x1 + 5 filter2_3_A(x1,x2,x3) = x1 + x2 + 7 filter2_4#_A(x1,x2,x3,x4) = x2 + 7 false_0_A() = 1 filter_2#_A(x1,x2) = x1 + 7 filter_1_A(x1) = x1 + 7 app_A(x1,x2) = x1 + x2 + 1 true_0_A() = 1 f_1_A(x1) = x1 + 9 nil_0_A() = 1 map_2#!_A(x1,x2) = x1 + x2 + 43 cons_2!_A(x1,x2) = 39 app#!_A(x1,x2) = x1 + x2 + 47 map_1!_A(x1) = 42 filter2_3!_A(x1,x2,x3) = 46 filter2_4#!_A(x1,x2,x3,x4) = x2 + x4 + 47 false_0!_A() = 34 filter_2#!_A(x1,x2) = x1 + x2 + 37 filter_1!_A(x1) = 36 app!_A(x1,x2) = x1 + 40 true_0!_A() = 38 f_1!_A(x1) = 39 nil_0!_A() = 37 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{1, x2 - 75} cons_2_A(x1,x2) = max{74, x1 + 12, x2} app#_A(x1,x2) = max{1, x2 - 63} map_1_A(x1) = max{15, x1 - 7} filter2_3_A(x1,x2,x3) = max{46, x1 - 6, x2 - 7, x3 + 5} filter2_4#_A(x1,x2,x3,x4) = max{1, x4 - 75} false_0_A = 0 filter_2#_A(x1,x2) = max{1, x2 - 75} filter_1_A(x1) = max{3, x1 - 4} app_A(x1,x2) = max{x1 + 2, x2 + 2} true_0_A = 1 f_1_A(x1) = x1 + 13 nil_0_A = 10 map_2#!_A(x1,x2) = max{31, x2 - 75} cons_2!_A(x1,x2) = max{29, x1 - 11} app#!_A(x1,x2) = max{30, x1 - 14, x2 - 76} map_1!_A(x1) = 24 filter2_3!_A(x1,x2,x3) = max{0, x2 - 2} filter2_4#!_A(x1,x2,x3,x4) = max{31, x3 - 10} false_0!_A = 33 filter_2#!_A(x1,x2) = max{32, x1 - 13, x2 - 21} filter_1!_A(x1) = max{0, x1 - 12} app!_A(x1,x2) = max{33, x1 + 13, x2 - 11} true_0!_A = 33 f_1!_A(x1) = max{19, x1 - 48} nil_0!_A = 1 partial status: pi(map_2#) = [2] pi(cons_2) = [1, 2] pi(app#) = [2] pi(map_1) = [] pi(filter2_3) = [] pi(filter2_4#) = [4] pi(false_0) = [] pi(filter_2#) = [2] pi(filter_1) = [1] pi(app) = [1, 2] pi(true_0) = [] pi(f_1) = [1] pi(nil_0) = [] The following rules are removed: p1, p2, p3, p4, p5, p6, p7, p8, p9 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: copy_3#(s_1(x),y,z) -> copy_3#(x,y,cons_2(f_1(y),z)) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(copy_0(),y) -> copy_1(y) r4: app(copy_1(x1),y) -> copy_2(x1,y) r5: app(copy_2(x1,x2),y) -> copy_3(x1,x2,y) r6: app(f_0(),y) -> f_1(y) r7: app(filter_0(),y) -> filter_1(y) r8: app(filter_1(x1),y) -> filter_2(x1,y) r9: app(filter2_0(),y) -> filter2_1(y) r10: app(filter2_1(x1),y) -> filter2_2(x1,y) r11: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r12: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r13: app(map_0(),y) -> map_1(y) r14: app(map_1(x1),y) -> map_2(x1,y) r15: app(s_0(),y) -> s_1(y) r16: f_1(cons_2(nil_0(),y)) -> y r17: f_1(cons_2(f_1(cons_2(nil_0(),y)),z)) -> copy_3(n_0(),y,z) r18: copy_3(|0|_0(),y,z) -> f_1(z) r19: copy_3(s_1(x),y,z) -> copy_3(x,y,cons_2(f_1(y),z)) r20: map_2(|fun|,nil_0()) -> nil_0() r21: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r22: filter_2(|fun|,nil_0()) -> nil_0() r23: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r24: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r25: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r16, r17 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: copy_3#_A(x1,x2,x3) = x1 + x3 s_1_A(x1) = x1 + 3 cons_2_A(x1,x2) = x2 + 2 f_1_A(x1) = x1 + 4 nil_0_A() = 3 copy_3_A(x1,x2,x3) = x1 + x3 + 2 n_0_A() = 1 copy_3#!_A(x1,x2,x3) = x1 + x3 + 3 s_1!_A(x1) = 0 cons_2!_A(x1,x2) = x2 + 5 f_1!_A(x1) = 5 nil_0!_A() = 0 copy_3!_A(x1,x2,x3) = x1 + 1 n_0!_A() = 4 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: copy_3#_A(x1,x2,x3) = max{0, x1 - 3, x2 - 1} s_1_A(x1) = max{2, x1} cons_2_A(x1,x2) = max{x1 - 8, x2 + 40} f_1_A(x1) = max{68, x1 + 24} nil_0_A = 55 copy_3_A(x1,x2,x3) = max{65, x1 - 26, x2 - 46, x3 - 61} n_0_A = 12 copy_3#!_A(x1,x2,x3) = max{20, x1 - 22, x2 - 2, x3 - 17} s_1!_A(x1) = max{2, x1 - 23} cons_2!_A(x1,x2) = max{19, x1 - 65, x2 + 14} f_1!_A(x1) = max{14, x1 - 48} nil_0!_A = 0 copy_3!_A(x1,x2,x3) = max{13, x1 - 21, x3 - 60} n_0!_A = 15 partial status: pi(copy_3#) = [2, 3] pi(s_1) = [] pi(cons_2) = [1, 2] pi(f_1) = [1] pi(nil_0) = [] pi(copy_3) = [] pi(n_0) = [] The following rules are removed: p1 Then no dependency pair remains.