YES We show the termination of the TRS R: app(f(),app(g(),x)) -> app(g(),app(f(),app(f(),x))) app(f(),app(h(),x)) -> app(h(),app(g(),x)) 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(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(g_0(),y) -> g_1(y) app(h_0(),y) -> h_1(y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) f_1(g_1(x)) -> g_1(f_1(f_1(x))) f_1(h_1(x)) -> h_1(g_1(x)) 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#(f_0(),y) -> f_1#(y) p2: app#(filter_1(x1),y) -> filter_2#(x1,y) p3: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p4: app#(map_1(x1),y) -> map_2#(x1,y) p5: f_1#(g_1(x)) -> f_1#(f_1(x)) p6: f_1#(g_1(x)) -> f_1#(x) p7: map_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p8: map_2#(|fun|,cons_2(x,xs)) -> map_2#(|fun|,xs) p9: filter_2#(|fun|,cons_2(x,xs)) -> filter2_4#(app(|fun|,x),|fun|,x,xs) p10: filter_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p11: filter2_4#(true_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) p12: 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(f_0(),y) -> f_1(y) r4: app(filter_0(),y) -> filter_1(y) r5: app(filter_1(x1),y) -> filter_2(x1,y) r6: app(filter2_0(),y) -> filter2_1(y) r7: app(filter2_1(x1),y) -> filter2_2(x1,y) r8: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r9: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r10: app(g_0(),y) -> g_1(y) r11: app(h_0(),y) -> h_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: f_1(g_1(x)) -> g_1(f_1(f_1(x))) r15: f_1(h_1(x)) -> h_1(g_1(x)) r16: map_2(|fun|,nil_0()) -> nil_0() r17: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r18: filter_2(|fun|,nil_0()) -> nil_0() r19: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r20: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r21: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The estimated dependency graph contains the following SCCs: {p2, p3, p4, p7, p8, p9, p10, p11, p12} {p5, p6} -- 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(f_0(),y) -> f_1(y) r4: app(filter_0(),y) -> filter_1(y) r5: app(filter_1(x1),y) -> filter_2(x1,y) r6: app(filter2_0(),y) -> filter2_1(y) r7: app(filter2_1(x1),y) -> filter2_2(x1,y) r8: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r9: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r10: app(g_0(),y) -> g_1(y) r11: app(h_0(),y) -> h_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: f_1(g_1(x)) -> g_1(f_1(f_1(x))) r15: f_1(h_1(x)) -> h_1(g_1(x)) r16: map_2(|fun|,nil_0()) -> nil_0() r17: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r18: filter_2(|fun|,nil_0()) -> nil_0() r19: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r20: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r21: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r1, r4, r6, r10, r11, r12, r16, r18 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!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{1, x1 - 47, x2 - 28} cons_2_A(x1,x2) = max{27, x1 + 23, x2 + 23} app#_A(x1,x2) = max{1, x1 - 47, x2 - 5} map_1_A(x1) = x1 + 11 filter2_3_A(x1,x2,x3) = max{x1 - 13, x2 + 4, x3 + 39} filter2_4#_A(x1,x2,x3,x4) = max{1, x2 - 47, x3 - 8, x4 - 5} false_0_A = 1 filter_2#_A(x1,x2) = max{1, x1 - 47, x2 - 28} filter_1_A(x1) = max{2, x1 + 1} app_A(x1,x2) = max{x1 - 16, x2 + 54} true_0_A = 21 cons_0_A = 0 cons_1_A(x1) = x1 + 39 filter_0_A = 13 filter2_0_A = 0 filter2_1_A(x1) = max{15, x1 - 13} g_0_A = 15 g_1_A(x1) = max{26, x1 - 57} h_0_A = 0 h_1_A(x1) = max{54, x1 - 27} map_0_A = 0 map_2_A(x1,x2) = max{48, x1 - 22, x2 - 22} nil_0_A = 27 filter_2_A(x1,x2) = max{26, x2} map_2#!_A(x1,x2) = max{2, x2 - 1} cons_2!_A(x1,x2) = max{x1 + 16, x2 + 22} app#!_A(x1,x2) = max{21, x2 + 3} map_1!_A(x1) = 1 filter2_3!_A(x1,x2,x3) = max{x1 + 18, x2 + 25, x3 + 18} filter2_4#!_A(x1,x2,x3,x4) = max{19, x4 - 1} false_0!_A = 5 filter_2#!_A(x1,x2) = max{4, x2 - 5} filter_1!_A(x1) = 24 app!_A(x1,x2) = max{25, x1 + 12, x2 + 23} true_0!_A = 0 cons_0!_A = 1 cons_1!_A(x1) = max{19, x1 - 1} filter_0!_A = 25 filter2_0!_A = 1 filter2_1!_A(x1) = 0 g_0!_A = 27 g_1!_A(x1) = max{26, x1 - 115} h_0!_A = 1 h_1!_A(x1) = 24 map_0!_A = 1 map_2!_A(x1,x2) = max{22, x2 - 28} nil_0!_A = 0 filter_2!_A(x1,x2) = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{1, x1 - 50, x2 - 16} cons_2_A(x1,x2) = max{x1 + 15, x2 + 7} app#_A(x1,x2) = max{1, x1 - 50, x2 - 1} map_1_A(x1) = max{16, x1 + 15} filter2_3_A(x1,x2,x3) = max{x1 + 15, x2 + 1, x3 + 49} filter2_4#_A(x1,x2,x3,x4) = max{1, x2 - 49, x3 - 1, x4 - 9} false_0_A = 49 filter_2#_A(x1,x2) = max{1, x1 - 49, x2 - 16} filter_1_A(x1) = x1 + 16 app_A(x1,x2) = max{64, x1 - 34, x2 + 49} true_0_A = 49 cons_0_A = 16 cons_1_A(x1) = x1 + 35 filter_0_A = 16 filter2_0_A = 0 filter2_1_A(x1) = x1 + 31 g_0_A = 0 g_1_A(x1) = max{50, x1 - 54} h_0_A = 32 h_1_A(x1) = max{50, x1 - 51} map_0_A = 16 map_2_A(x1,x2) = max{x1 - 19, x2 + 64} nil_0_A = 65 filter_2_A(x1,x2) = max{50, x1 - 40, x2 + 42} map_2#!_A(x1,x2) = max{1, x2 - 9} cons_2!_A(x1,x2) = max{x1 + 9, x2 - 64} app#!_A(x1,x2) = x2 + 5 map_1!_A(x1) = max{14, x1 - 17} filter2_3!_A(x1,x2,x3) = max{15, x1 - 50, x2 + 8} filter2_4#!_A(x1,x2,x3,x4) = max{7, x2 - 1, x3 - 1, x4 + 6} false_0!_A = 3 filter_2#!_A(x1,x2) = max{4, x2 - 9} filter_1!_A(x1) = 1 app!_A(x1,x2) = max{13, x1 - 17, x2 + 11} true_0!_A = 9 cons_0!_A = 1 cons_1!_A(x1) = max{14, x1 - 1} filter_0!_A = 2 filter2_0!_A = 16 filter2_1!_A(x1) = 15 g_0!_A = 2 g_1!_A(x1) = max{1, x1 - 162} h_0!_A = 1 h_1!_A(x1) = max{14, x1 - 52} map_0!_A = 1 map_2!_A(x1,x2) = max{15, x2 - 66} nil_0!_A = 1 filter_2!_A(x1,x2) = max{2, x1 - 86, x2 - 3} partial status: pi(map_2#) = [] pi(cons_2) = [] pi(app#) = [] pi(map_1) = [1] pi(filter2_3) = [] pi(filter2_4#) = [] pi(false_0) = [] pi(filter_2#) = [] pi(filter_1) = [1] pi(app) = [1, 2] pi(true_0) = [] pi(cons_0) = [] pi(cons_1) = [1] pi(filter_0) = [] pi(filter2_0) = [] pi(filter2_1) = [1] pi(g_0) = [] pi(g_1) = [] pi(h_0) = [] pi(h_1) = [] pi(map_0) = [] pi(map_2) = [2] pi(nil_0) = [] pi(filter_2) = [] 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: f_1#(g_1(x)) -> f_1#(f_1(x)) p2: f_1#(g_1(x)) -> f_1#(x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(f_0(),y) -> f_1(y) r4: app(filter_0(),y) -> filter_1(y) r5: app(filter_1(x1),y) -> filter_2(x1,y) r6: app(filter2_0(),y) -> filter2_1(y) r7: app(filter2_1(x1),y) -> filter2_2(x1,y) r8: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r9: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r10: app(g_0(),y) -> g_1(y) r11: app(h_0(),y) -> h_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: f_1(g_1(x)) -> g_1(f_1(f_1(x))) r15: f_1(h_1(x)) -> h_1(g_1(x)) r16: map_2(|fun|,nil_0()) -> nil_0() r17: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r18: filter_2(|fun|,nil_0()) -> nil_0() r19: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r20: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r21: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r14, r15 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!): max/plus interpretation on natural numbers: f_1#_A(x1) = max{0, x1 - 33} g_1_A(x1) = x1 + 32 f_1_A(x1) = x1 h_1_A(x1) = 2 f_1#!_A(x1) = 0 g_1!_A(x1) = max{2, x1 - 28} f_1!_A(x1) = max{0, x1 - 29} h_1!_A(x1) = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f_1#_A(x1) = max{0, x1 - 4} g_1_A(x1) = max{2, x1} f_1_A(x1) = max{3, x1} h_1_A(x1) = max{4, x1 - 3} f_1#!_A(x1) = 1 g_1!_A(x1) = 6 f_1!_A(x1) = 2 h_1!_A(x1) = 1 partial status: pi(f_1#) = [1] pi(g_1) = [1] pi(f_1) = [] pi(h_1) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f_1#(g_1(x)) -> f_1#(f_1(x)) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(f_0(),y) -> f_1(y) r4: app(filter_0(),y) -> filter_1(y) r5: app(filter_1(x1),y) -> filter_2(x1,y) r6: app(filter2_0(),y) -> filter2_1(y) r7: app(filter2_1(x1),y) -> filter2_2(x1,y) r8: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r9: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r10: app(g_0(),y) -> g_1(y) r11: app(h_0(),y) -> h_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: f_1(g_1(x)) -> g_1(f_1(f_1(x))) r15: f_1(h_1(x)) -> h_1(g_1(x)) r16: map_2(|fun|,nil_0()) -> nil_0() r17: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r18: filter_2(|fun|,nil_0()) -> nil_0() r19: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r20: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r21: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f_1#(g_1(x)) -> f_1#(f_1(x)) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(f_0(),y) -> f_1(y) r4: app(filter_0(),y) -> filter_1(y) r5: app(filter_1(x1),y) -> filter_2(x1,y) r6: app(filter2_0(),y) -> filter2_1(y) r7: app(filter2_1(x1),y) -> filter2_2(x1,y) r8: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r9: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r10: app(g_0(),y) -> g_1(y) r11: app(h_0(),y) -> h_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: f_1(g_1(x)) -> g_1(f_1(f_1(x))) r15: f_1(h_1(x)) -> h_1(g_1(x)) r16: map_2(|fun|,nil_0()) -> nil_0() r17: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r18: filter_2(|fun|,nil_0()) -> nil_0() r19: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r20: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r21: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r14, r15 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!): max/plus interpretation on natural numbers: f_1#_A(x1) = max{28, x1 + 15} g_1_A(x1) = max{8, x1 - 14} f_1_A(x1) = max{13, x1 - 14} h_1_A(x1) = max{2, x1 - 9} f_1#!_A(x1) = 1 g_1!_A(x1) = 4 f_1!_A(x1) = max{3, x1 - 3} h_1!_A(x1) = 2 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f_1#_A(x1) = max{0, x1 - 13} g_1_A(x1) = max{15, x1 + 1} f_1_A(x1) = max{14, x1} h_1_A(x1) = 4 f_1#!_A(x1) = max{9, x1 - 4} g_1!_A(x1) = 8 f_1!_A(x1) = 12 h_1!_A(x1) = max{7, x1 - 2} partial status: pi(f_1#) = [] pi(g_1) = [] pi(f_1) = [] pi(h_1) = [] The following rules are removed: p1 Then no dependency pair remains.