YES We show the termination of the TRS R: app(D(),t()) -> |1|() app(D(),constant()) -> |0|() app(D(),app(app(+(),x),y)) -> app(app(+(),app(D(),x)),app(D(),y)) app(D(),app(app(*(),x),y)) -> app(app(+(),app(app(*(),y),app(D(),x))),app(app(*(),x),app(D(),y))) app(D(),app(app(-(),x),y)) -> app(app(-(),app(D(),x)),app(D(),y)) 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) Instead we prove termination of the uncurried system: app(*_0(),y) -> *_1(y) app(*_1(x1),y) -> *_2(x1,y) app(+_0(),y) -> +_1(y) app(+_1(x1),y) -> +_2(x1,y) app(-_0(),y) -> -_1(y) app(-_1(x1),y) -> -_2(x1,y) app(D_0(),y) -> D_1(y) app(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,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) D_1(t_0()) -> |1|_0() D_1(constant_0()) -> |0|_0() D_1(+_2(x,y)) -> +_2(D_1(x),D_1(y)) D_1(*_2(x,y)) -> +_2(*_2(y,D_1(x)),*_2(x,D_1(y))) D_1(-_2(x,y)) -> -_2(D_1(x),D_1(y)) map_2(f,nil_0()) -> nil_0() map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) filter_2(f,nil_0()) -> nil_0() filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(D_0(),y) -> D_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: D_1#(+_2(x,y)) -> D_1#(x) p6: D_1#(+_2(x,y)) -> D_1#(y) p7: D_1#(*_2(x,y)) -> D_1#(x) p8: D_1#(*_2(x,y)) -> D_1#(y) p9: D_1#(-_2(x,y)) -> D_1#(x) p10: D_1#(-_2(x,y)) -> D_1#(y) p11: map_2#(f,cons_2(x,xs)) -> app#(f,x) p12: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p13: filter_2#(f,cons_2(x,xs)) -> filter2_4#(app(f,x),f,x,xs) p14: filter_2#(f,cons_2(x,xs)) -> app#(f,x) p15: filter2_4#(true_0(),f,x,xs) -> filter_2#(f,xs) p16: filter2_4#(false_0(),f,x,xs) -> filter_2#(f,xs) and R consists of: r1: app(*_0(),y) -> *_1(y) r2: app(*_1(x1),y) -> *_2(x1,y) r3: app(+_0(),y) -> +_1(y) r4: app(+_1(x1),y) -> +_2(x1,y) r5: app(-_0(),y) -> -_1(y) r6: app(-_1(x1),y) -> -_2(x1,y) r7: app(D_0(),y) -> D_1(y) r8: app(cons_0(),y) -> cons_1(y) r9: app(cons_1(x1),y) -> cons_2(x1,y) r10: app(filter_0(),y) -> filter_1(y) r11: app(filter_1(x1),y) -> filter_2(x1,y) r12: app(filter2_0(),y) -> filter2_1(y) r13: app(filter2_1(x1),y) -> filter2_2(x1,y) r14: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r15: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: D_1(t_0()) -> |1|_0() r19: D_1(constant_0()) -> |0|_0() r20: D_1(+_2(x,y)) -> +_2(D_1(x),D_1(y)) r21: D_1(*_2(x,y)) -> +_2(*_2(y,D_1(x)),*_2(x,D_1(y))) r22: D_1(-_2(x,y)) -> -_2(D_1(x),D_1(y)) r23: map_2(f,nil_0()) -> nil_0() r24: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r25: filter_2(f,nil_0()) -> nil_0() r26: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r27: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r28: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The estimated dependency graph contains the following SCCs: {p2, p3, p4, p11, p12, p13, p14, p15, p16} {p5, p6, p7, p8, p9, p10} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> app#(f,x) p2: app#(map_1(x1),y) -> map_2#(x1,y) p3: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p4: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p5: filter2_4#(false_0(),f,x,xs) -> filter_2#(f,xs) p6: filter_2#(f,cons_2(x,xs)) -> app#(f,x) p7: app#(filter_1(x1),y) -> filter_2#(x1,y) p8: filter_2#(f,cons_2(x,xs)) -> filter2_4#(app(f,x),f,x,xs) p9: filter2_4#(true_0(),f,x,xs) -> filter_2#(f,xs) and R consists of: r1: app(*_0(),y) -> *_1(y) r2: app(*_1(x1),y) -> *_2(x1,y) r3: app(+_0(),y) -> +_1(y) r4: app(+_1(x1),y) -> +_2(x1,y) r5: app(-_0(),y) -> -_1(y) r6: app(-_1(x1),y) -> -_2(x1,y) r7: app(D_0(),y) -> D_1(y) r8: app(cons_0(),y) -> cons_1(y) r9: app(cons_1(x1),y) -> cons_2(x1,y) r10: app(filter_0(),y) -> filter_1(y) r11: app(filter_1(x1),y) -> filter_2(x1,y) r12: app(filter2_0(),y) -> filter2_1(y) r13: app(filter2_1(x1),y) -> filter2_2(x1,y) r14: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r15: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: D_1(t_0()) -> |1|_0() r19: D_1(constant_0()) -> |0|_0() r20: D_1(+_2(x,y)) -> +_2(D_1(x),D_1(y)) r21: D_1(*_2(x,y)) -> +_2(*_2(y,D_1(x)),*_2(x,D_1(y))) r22: D_1(-_2(x,y)) -> -_2(D_1(x),D_1(y)) r23: map_2(f,nil_0()) -> nil_0() r24: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r25: filter_2(f,nil_0()) -> nil_0() r26: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r27: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r28: filter2_4(false_0(),f,x,xs) -> filter_2(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: map_2#_A(x1,x2) = max{2, x1 - 32, x2 - 23} cons_2_A(x1,x2) = max{x1 + 15, x2 + 22} app#_A(x1,x2) = max{2, x1 - 45, x2 - 8} map_1_A(x1) = x1 + 13 filter2_3_A(x1,x2,x3) = max{44, x1 + 10, x2 + 10, x3 + 10} filter2_4#_A(x1,x2,x3,x4) = max{2, x2 - 45, x3 - 35, x4 - 8} false_0_A = 12 filter_2#_A(x1,x2) = max{2, x1 - 45, x2 - 21} filter_1_A(x1) = x1 + 46 app_A(x1,x2) = max{10, x1 - 209, x2 + 2} true_0_A = 3 map_2#!_A(x1,x2) = 39 cons_2!_A(x1,x2) = max{41, x1 + 32, x2 + 4} app#!_A(x1,x2) = max{40, x2 + 21} map_1!_A(x1) = x1 + 36 filter2_3!_A(x1,x2,x3) = max{38, x1 + 32, x2 + 29, x3 + 34} filter2_4#!_A(x1,x2,x3,x4) = max{39, x4 + 1} false_0!_A = 1 filter_2#!_A(x1,x2) = max{0, x2 - 22} filter_1!_A(x1) = max{38, x1 - 14} app!_A(x1,x2) = max{37, x1 - 12} true_0!_A = 32 2. 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) = 0 cons_2_A(x1,x2) = 10 app#_A(x1,x2) = 0 map_1_A(x1) = x1 + 3 filter2_3_A(x1,x2,x3) = x1 + x2 + x3 + 7 filter2_4#_A(x1,x2,x3,x4) = 0 false_0_A() = 1 filter_2#_A(x1,x2) = 0 filter_1_A(x1) = x1 + 3 app_A(x1,x2) = x1 + x2 + 1 true_0_A() = 1 map_2#!_A(x1,x2) = 5 cons_2!_A(x1,x2) = 7 app#!_A(x1,x2) = 6 map_1!_A(x1) = 4 filter2_3!_A(x1,x2,x3) = 4 filter2_4#!_A(x1,x2,x3,x4) = 1 false_0!_A() = 3 filter_2#!_A(x1,x2) = 0 filter_1!_A(x1) = 1 app!_A(x1,x2) = 3 true_0!_A() = 1 partial status: pi(map_2#) = [2] pi(cons_2) = [1, 2] pi(app#) = [2] pi(map_1) = [] pi(filter2_3) = [2, 3] pi(filter2_4#) = [4] pi(false_0) = [] pi(filter_2#) = [2] pi(filter_1) = [1] pi(app) = [2] pi(true_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: D_1#(+_2(x,y)) -> D_1#(x) p2: D_1#(-_2(x,y)) -> D_1#(y) p3: D_1#(-_2(x,y)) -> D_1#(x) p4: D_1#(*_2(x,y)) -> D_1#(y) p5: D_1#(*_2(x,y)) -> D_1#(x) p6: D_1#(+_2(x,y)) -> D_1#(y) and R consists of: r1: app(*_0(),y) -> *_1(y) r2: app(*_1(x1),y) -> *_2(x1,y) r3: app(+_0(),y) -> +_1(y) r4: app(+_1(x1),y) -> +_2(x1,y) r5: app(-_0(),y) -> -_1(y) r6: app(-_1(x1),y) -> -_2(x1,y) r7: app(D_0(),y) -> D_1(y) r8: app(cons_0(),y) -> cons_1(y) r9: app(cons_1(x1),y) -> cons_2(x1,y) r10: app(filter_0(),y) -> filter_1(y) r11: app(filter_1(x1),y) -> filter_2(x1,y) r12: app(filter2_0(),y) -> filter2_1(y) r13: app(filter2_1(x1),y) -> filter2_2(x1,y) r14: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r15: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: D_1(t_0()) -> |1|_0() r19: D_1(constant_0()) -> |0|_0() r20: D_1(+_2(x,y)) -> +_2(D_1(x),D_1(y)) r21: D_1(*_2(x,y)) -> +_2(*_2(y,D_1(x)),*_2(x,D_1(y))) r22: D_1(-_2(x,y)) -> -_2(D_1(x),D_1(y)) r23: map_2(f,nil_0()) -> nil_0() r24: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r25: filter_2(f,nil_0()) -> nil_0() r26: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r27: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r28: filter2_4(false_0(),f,x,xs) -> filter_2(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: D_1#_A(x1) = 0 +_2_A(x1,x2) = max{2, x1 - 23, x2 - 23} -_2_A(x1,x2) = max{2, x1 - 31, x2 - 31} *_2_A(x1,x2) = max{8, x1 - 12, x2 - 34} D_1#!_A(x1) = 11 +_2!_A(x1,x2) = x1 + 11 -_2!_A(x1,x2) = max{2, x1 - 26, x2 - 49} *_2!_A(x1,x2) = max{0, x1 - 39, x2 - 27} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: D_1#_A(x1) = x1 +_2_A(x1,x2) = x1 + x2 + 5 -_2_A(x1,x2) = x1 + x2 + 5 *_2_A(x1,x2) = x1 + x2 + 5 D_1#!_A(x1) = x1 +_2!_A(x1,x2) = 5 -_2!_A(x1,x2) = 2 *_2!_A(x1,x2) = 3 partial status: pi(D_1#) = [] pi(+_2) = [1] pi(-_2) = [] pi(*_2) = [] The following rules are removed: p1, p2, p3, p4, p5, p6 Then no dependency pair remains.