YES We show the termination of the TRS R: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) app(app(map(),f),nil()) -> nil() app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) app(app(filter(),f),nil()) -> nil() app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(|:|(),app(app(|:|(),x),y)),z) -> app#(app(|:|(),x),app(app(|:|(),y),z)) p2: app#(app(|:|(),app(app(|:|(),x),y)),z) -> app#(app(|:|(),y),z) p3: app#(app(|:|(),app(app(|:|(),x),y)),z) -> app#(|:|(),y) p4: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) p5: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(+(),app(app(|:|(),x),z)) p6: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(app(|:|(),x),z) p7: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(|:|(),x) p8: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(app(|:|(),y),z) p9: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(|:|(),y) p10: app#(app(|:|(),z),app(app(+(),x),app(f,y))) -> app#(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) p11: app#(app(|:|(),z),app(app(+(),x),app(f,y))) -> app#(|:|(),app(app(g(),z),y)) p12: app#(app(|:|(),z),app(app(+(),x),app(f,y))) -> app#(app(g(),z),y) p13: app#(app(|:|(),z),app(app(+(),x),app(f,y))) -> app#(g(),z) p14: app#(app(|:|(),z),app(app(+(),x),app(f,y))) -> app#(app(+(),x),a()) p15: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(cons(),app(f,x)),app(app(map(),f),xs)) p16: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(cons(),app(f,x)) p17: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(f,x) p18: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) p19: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(app(app(filter2(),app(f,x)),f),x),xs) p20: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(app(filter2(),app(f,x)),f),x) p21: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(filter2(),app(f,x)),f) p22: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(filter2(),app(f,x)) p23: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(f,x) p24: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(cons(),x),app(app(filter(),f),xs)) p25: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(cons(),x) p26: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(filter(),f),xs) p27: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(filter(),f) p28: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(app(filter(),f),xs) p29: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(filter(),f) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The estimated dependency graph contains the following SCCs: {p17, p18, p19, p23, p26, p28} {p1, p2, p6, p8} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(f,x) p2: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(app(filter(),f),xs) p3: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(app(app(filter2(),app(f,x)),f),x),xs) p4: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(filter(),f),xs) p5: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) p6: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(f,x) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The set of usable rules consists of r4, r6 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: app#_A(x1,x2) = max{0, x2 - 7} app_A(x1,x2) = max{6, x1, x2} filter_A = 3 cons_A = 3 filter2_A = 5 false_A = 5 true_A = 2 map_A = 7 nil_A = 8 app#!_A(x1,x2) = 0 app!_A(x1,x2) = 3 filter!_A = 5 cons!_A = 5 filter2!_A = 4 false!_A = 0 true!_A = 0 map!_A = 6 nil!_A = 1 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{0, x2 - 4} app_A(x1,x2) = max{24, x1 + 4, x2} filter_A = 8 cons_A = 12 filter2_A = 7 false_A = 3 true_A = 3 map_A = 22 nil_A = 31 app#!_A(x1,x2) = x2 + 6 app!_A(x1,x2) = 3 filter!_A = 36 cons!_A = 36 filter2!_A = 35 false!_A = 4 true!_A = 4 map!_A = 3 nil!_A = 3 partial status: pi(app#) = [] pi(app) = [1] pi(filter) = [] pi(cons) = [] pi(filter2) = [] pi(false) = [] pi(true) = [] pi(map) = [] pi(nil) = [] The following rules are removed: p1, p6 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(app(filter(),f),xs) p2: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(app(app(filter2(),app(f,x)),f),x),xs) p3: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(filter(),f),xs) p4: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The estimated dependency graph contains the following SCCs: {p1, p2, p3} {p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(app(filter(),f),xs) p2: app#(app(filter(),f),app(app(cons(),x),xs)) -> app#(app(app(app(filter2(),app(f,x)),f),x),xs) p3: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(filter(),f),xs) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The set of usable rules consists of (no rules) 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: app#_A(x1,x2) = 0 app_A(x1,x2) = 26 filter2_A = 3 false_A = 1 filter_A = 35 cons_A = 13 true_A = 26 app#!_A(x1,x2) = 0 app!_A(x1,x2) = max{x1 + 5, x2 + 5} filter2!_A = 6 false!_A = 0 filter!_A = 7 cons!_A = 0 true!_A = 17 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = 0 app_A(x1,x2) = max{20, x1 + 5, x2 - 5} filter2_A = 15 false_A = 17 filter_A = 18 cons_A = 29 true_A = 21 app#!_A(x1,x2) = max{65, x2 + 7} app!_A(x1,x2) = x1 + 30 filter2!_A = 44 false!_A = 44 filter!_A = 45 cons!_A = 60 true!_A = 49 partial status: pi(app#) = [2] pi(app) = [2] pi(filter2) = [] pi(false) = [] pi(filter) = [] pi(cons) = [] pi(true) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(app(filter2(),false()),f),x),xs) -> app#(app(filter(),f),xs) p2: app#(app(app(app(filter2(),true()),f),x),xs) -> app#(app(filter(),f),xs) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The estimated dependency graph contains the following SCCs: (no SCCs) -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The set of usable rules consists of r4, r6 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: app#_A(x1,x2) = max{0, x2 - 4} app_A(x1,x2) = max{17, x1 - 29, x2 + 3} map_A = 0 cons_A = 13 nil_A = 18 filter_A = 19 app#!_A(x1,x2) = max{3, x1 - 35, x2 - 18} app!_A(x1,x2) = max{3, x1 - 22, x2 - 112} map!_A = 2 cons!_A = 1 nil!_A = 0 filter!_A = 4 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{0, x2 - 5} app_A(x1,x2) = max{11, x1 - 18, x2 + 4} map_A = 27 cons_A = 6 nil_A = 12 filter_A = 31 app#!_A(x1,x2) = max{3, x1 - 110, x2 - 91} app!_A(x1,x2) = max{4, x1 - 106, x2 - 163} map!_A = 2 cons!_A = 1 nil!_A = 0 filter!_A = 1 partial status: pi(app#) = [2] pi(app) = [2] pi(map) = [] pi(cons) = [] pi(nil) = [] pi(filter) = [] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(|:|(),app(app(|:|(),x),y)),z) -> app#(app(|:|(),x),app(app(|:|(),y),z)) p2: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(app(|:|(),y),z) p3: app#(app(|:|(),app(app(+(),x),y)),z) -> app#(app(|:|(),x),z) p4: app#(app(|:|(),app(app(|:|(),x),y)),z) -> app#(app(|:|(),y),z) and R consists of: r1: app(app(|:|(),app(app(|:|(),x),y)),z) -> app(app(|:|(),x),app(app(|:|(),y),z)) r2: app(app(|:|(),app(app(+(),x),y)),z) -> app(app(+(),app(app(|:|(),x),z)),app(app(|:|(),y),z)) r3: app(app(|:|(),z),app(app(+(),x),app(f,y))) -> app(app(|:|(),app(app(g(),z),y)),app(app(+(),x),a())) r4: app(app(map(),f),nil()) -> nil() r5: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r6: app(app(filter(),f),nil()) -> nil() r7: app(app(filter(),f),app(app(cons(),x),xs)) -> app(app(app(app(filter2(),app(f,x)),f),x),xs) r8: app(app(app(app(filter2(),true()),f),x),xs) -> app(app(cons(),x),app(app(filter(),f),xs)) r9: app(app(app(app(filter2(),false()),f),x),xs) -> app(app(filter(),f),xs) The set of usable rules consists of r4, r6 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: app#_A(x1,x2) = max{0, x1 - 6} app_A(x1,x2) = max{x1, x2} |:|_A = 0 +_A = 5 map_A = 1 nil_A = 6 filter_A = 5 app#!_A(x1,x2) = max{4, x1 - 14} app!_A(x1,x2) = max{5, x1 - 10, x2 - 13} |:|!_A = 3 +!_A = 6 map!_A = 1 nil!_A = 0 filter!_A = 1 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = 0 app_A(x1,x2) = max{49, x1 + 45, x2 - 17} |:|_A = 4 +_A = 1 map_A = 22 nil_A = 16 filter_A = 22 app#!_A(x1,x2) = max{55, x1 - 78} app!_A(x1,x2) = max{22, x1 - 72, x2 - 38} |:|!_A = 54 +!_A = 52 map!_A = 54 nil!_A = 0 filter!_A = 66 partial status: pi(app#) = [1] pi(app) = [1, 2] pi(|:|) = [] pi(+) = [] pi(map) = [] pi(nil) = [] pi(filter) = [] The following rules are removed: p1, p2, p3, p4 Then no dependency pair remains.