YES We show the termination of the TRS R: app(p(),app(s(),x)) -> x app(fact(),|0|()) -> app(s(),|0|()) app(fact(),app(s(),x)) -> app(app(*(),app(s(),x)),app(fact(),app(p(),app(s(),x)))) app(app(*(),|0|()),y) -> |0|() app(app(*(),app(s(),x)),y) -> app(app(+(),app(app(*(),x),y)),y) app(app(+(),x),|0|()) -> x app(app(+(),x),app(s(),y)) -> app(s(),app(app(+(),x),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(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,y) app(fact_0(),y) -> fact_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(p_0(),y) -> p_1(y) app(s_0(),y) -> s_1(y) p_1(s_1(x)) -> x fact_1(|0|_0()) -> s_1(|0|_0()) fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) *_2(|0|_0(),y) -> |0|_0() *_2(s_1(x),y) -> +_2(*_2(x,y),y) +_2(x,|0|_0()) -> x +_2(x,s_1(y)) -> s_1(+_2(x,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#(*_1(x1),y) -> *_2#(x1,y) p2: app#(+_1(x1),y) -> +_2#(x1,y) p3: app#(fact_0(),y) -> fact_1#(y) p4: app#(filter_1(x1),y) -> filter_2#(x1,y) p5: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p6: app#(map_1(x1),y) -> map_2#(x1,y) p7: app#(p_0(),y) -> p_1#(y) p8: fact_1#(s_1(x)) -> *_2#(s_1(x),fact_1(p_1(s_1(x)))) p9: fact_1#(s_1(x)) -> fact_1#(p_1(s_1(x))) p10: fact_1#(s_1(x)) -> p_1#(s_1(x)) p11: *_2#(s_1(x),y) -> +_2#(*_2(x,y),y) p12: *_2#(s_1(x),y) -> *_2#(x,y) p13: +_2#(x,s_1(y)) -> +_2#(x,y) p14: map_2#(f,cons_2(x,xs)) -> app#(f,x) p15: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p16: filter_2#(f,cons_2(x,xs)) -> filter2_4#(app(f,x),f,x,xs) p17: filter_2#(f,cons_2(x,xs)) -> app#(f,x) p18: filter2_4#(true_0(),f,x,xs) -> filter_2#(f,xs) p19: 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(cons_0(),y) -> cons_1(y) r6: app(cons_1(x1),y) -> cons_2(x1,y) r7: app(fact_0(),y) -> fact_1(y) r8: app(filter_0(),y) -> filter_1(y) r9: app(filter_1(x1),y) -> filter_2(x1,y) r10: app(filter2_0(),y) -> filter2_1(y) r11: app(filter2_1(x1),y) -> filter2_2(x1,y) r12: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r13: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r14: app(map_0(),y) -> map_1(y) r15: app(map_1(x1),y) -> map_2(x1,y) r16: app(p_0(),y) -> p_1(y) r17: app(s_0(),y) -> s_1(y) r18: p_1(s_1(x)) -> x r19: fact_1(|0|_0()) -> s_1(|0|_0()) r20: fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) r21: *_2(|0|_0(),y) -> |0|_0() r22: *_2(s_1(x),y) -> +_2(*_2(x,y),y) r23: +_2(x,|0|_0()) -> x r24: +_2(x,s_1(y)) -> s_1(+_2(x,y)) r25: map_2(f,nil_0()) -> nil_0() r26: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r27: filter_2(f,nil_0()) -> nil_0() r28: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r29: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r30: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The estimated dependency graph contains the following SCCs: {p4, p5, p6, p14, p15, p16, p17, p18, p19} {p9} {p12} {p13} -- 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(cons_0(),y) -> cons_1(y) r6: app(cons_1(x1),y) -> cons_2(x1,y) r7: app(fact_0(),y) -> fact_1(y) r8: app(filter_0(),y) -> filter_1(y) r9: app(filter_1(x1),y) -> filter_2(x1,y) r10: app(filter2_0(),y) -> filter2_1(y) r11: app(filter2_1(x1),y) -> filter2_2(x1,y) r12: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r13: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r14: app(map_0(),y) -> map_1(y) r15: app(map_1(x1),y) -> map_2(x1,y) r16: app(p_0(),y) -> p_1(y) r17: app(s_0(),y) -> s_1(y) r18: p_1(s_1(x)) -> x r19: fact_1(|0|_0()) -> s_1(|0|_0()) r20: fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) r21: *_2(|0|_0(),y) -> |0|_0() r22: *_2(s_1(x),y) -> +_2(*_2(x,y),y) r23: +_2(x,|0|_0()) -> x r24: +_2(x,s_1(y)) -> s_1(+_2(x,y)) r25: map_2(f,nil_0()) -> nil_0() r26: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r27: filter_2(f,nil_0()) -> nil_0() r28: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r29: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r30: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The set of usable rules consists of r16, r18 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: map_2#_A(x1,x2) = x1 + x2 + 3 cons_2_A(x1,x2) = x1 + x2 + 4 app#_A(x1,x2) = x1 + x2 + 2 map_1_A(x1) = x1 + 2 filter2_3_A(x1,x2,x3) = x1 + x2 + x3 + 6 filter2_4#_A(x1,x2,x3,x4) = x2 + x4 + 3 false_0_A() = 1 filter_2#_A(x1,x2) = x1 + x2 + 2 filter_1_A(x1) = x1 + 1 app_A(x1,x2) = x1 + x2 + 5 true_0_A() = 5 p_0_A() = 1 p_1_A(x1) = x1 s_1_A(x1) = x1 + 4 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = 1 cons_2_A(x1,x2) = max{15, x1 + 8} app#_A(x1,x2) = 1 map_1_A(x1) = x1 + 4 filter2_3_A(x1,x2,x3) = max{x1 - 7, x2 - 6, x3 + 4} filter2_4#_A(x1,x2,x3,x4) = 1 false_0_A = 4 filter_2#_A(x1,x2) = 1 filter_1_A(x1) = max{4, x1 - 2} app_A(x1,x2) = x2 + 3 true_0_A = 6 p_0_A = 4 p_1_A(x1) = max{3, x1 + 2} s_1_A(x1) = max{29, x1 + 18} map_2#!_A(x1,x2) = max{35, x1 + 12} cons_2!_A(x1,x2) = max{34, x1 - 7, x2 + 26} app#!_A(x1,x2) = max{32, x1 + 8} map_1!_A(x1) = max{36, x1 + 23} filter2_3!_A(x1,x2,x3) = 3 filter2_4#!_A(x1,x2,x3,x4) = max{33, x2 + 6, x4 + 27} false_0!_A = 1 filter_2#!_A(x1,x2) = max{33, x1 + 6, x2 - 15} filter_1!_A(x1) = x1 app!_A(x1,x2) = max{0, x1 - 5, x2 - 7} true_0!_A = 32 p_0!_A = 0 p_1!_A(x1) = 0 s_1!_A(x1) = x1 + 4 partial status: pi(map_2#) = [] pi(cons_2) = [] pi(app#) = [1, 2] pi(map_1) = [1] pi(filter2_3) = [1] pi(filter2_4#) = [] pi(false_0) = [] pi(filter_2#) = [1, 2] pi(filter_1) = [1] pi(app) = [1, 2] pi(true_0) = [] pi(p_0) = [] pi(p_1) = [] pi(s_1) = [1] 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: fact_1#(s_1(x)) -> fact_1#(p_1(s_1(x))) 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(cons_0(),y) -> cons_1(y) r6: app(cons_1(x1),y) -> cons_2(x1,y) r7: app(fact_0(),y) -> fact_1(y) r8: app(filter_0(),y) -> filter_1(y) r9: app(filter_1(x1),y) -> filter_2(x1,y) r10: app(filter2_0(),y) -> filter2_1(y) r11: app(filter2_1(x1),y) -> filter2_2(x1,y) r12: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r13: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r14: app(map_0(),y) -> map_1(y) r15: app(map_1(x1),y) -> map_2(x1,y) r16: app(p_0(),y) -> p_1(y) r17: app(s_0(),y) -> s_1(y) r18: p_1(s_1(x)) -> x r19: fact_1(|0|_0()) -> s_1(|0|_0()) r20: fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) r21: *_2(|0|_0(),y) -> |0|_0() r22: *_2(s_1(x),y) -> +_2(*_2(x,y),y) r23: +_2(x,|0|_0()) -> x r24: +_2(x,s_1(y)) -> s_1(+_2(x,y)) r25: map_2(f,nil_0()) -> nil_0() r26: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r27: filter_2(f,nil_0()) -> nil_0() r28: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r29: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r30: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The set of usable rules consists of r18 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: fact_1#_A(x1) = 1 s_1_A(x1) = x1 + 2 p_1_A(x1) = x1 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: fact_1#_A(x1) = max{1, x1 - 18} s_1_A(x1) = max{34, x1 + 17} p_1_A(x1) = max{2, x1 - 15} fact_1#!_A(x1) = max{1, x1 - 15} s_1!_A(x1) = max{24, x1 - 12} p_1!_A(x1) = max{25, x1 - 123} partial status: pi(fact_1#) = [] pi(s_1) = [1] pi(p_1) = [] 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: *_2#(s_1(x),y) -> *_2#(x,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(cons_0(),y) -> cons_1(y) r6: app(cons_1(x1),y) -> cons_2(x1,y) r7: app(fact_0(),y) -> fact_1(y) r8: app(filter_0(),y) -> filter_1(y) r9: app(filter_1(x1),y) -> filter_2(x1,y) r10: app(filter2_0(),y) -> filter2_1(y) r11: app(filter2_1(x1),y) -> filter2_2(x1,y) r12: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r13: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r14: app(map_0(),y) -> map_1(y) r15: app(map_1(x1),y) -> map_2(x1,y) r16: app(p_0(),y) -> p_1(y) r17: app(s_0(),y) -> s_1(y) r18: p_1(s_1(x)) -> x r19: fact_1(|0|_0()) -> s_1(|0|_0()) r20: fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) r21: *_2(|0|_0(),y) -> |0|_0() r22: *_2(s_1(x),y) -> +_2(*_2(x,y),y) r23: +_2(x,|0|_0()) -> x r24: +_2(x,s_1(y)) -> s_1(+_2(x,y)) r25: map_2(f,nil_0()) -> nil_0() r26: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r27: filter_2(f,nil_0()) -> nil_0() r28: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r29: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r30: 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: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: *_2#_A(x1,x2) = x1 s_1_A(x1) = x1 + 1 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: *_2#_A(x1,x2) = 0 s_1_A(x1) = max{5, x1 - 6} *_2#!_A(x1,x2) = 0 s_1!_A(x1) = max{5, x1 - 23} partial status: pi(*_2#) = [1] pi(s_1) = [1] 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: +_2#(x,s_1(y)) -> +_2#(x,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(cons_0(),y) -> cons_1(y) r6: app(cons_1(x1),y) -> cons_2(x1,y) r7: app(fact_0(),y) -> fact_1(y) r8: app(filter_0(),y) -> filter_1(y) r9: app(filter_1(x1),y) -> filter_2(x1,y) r10: app(filter2_0(),y) -> filter2_1(y) r11: app(filter2_1(x1),y) -> filter2_2(x1,y) r12: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r13: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r14: app(map_0(),y) -> map_1(y) r15: app(map_1(x1),y) -> map_2(x1,y) r16: app(p_0(),y) -> p_1(y) r17: app(s_0(),y) -> s_1(y) r18: p_1(s_1(x)) -> x r19: fact_1(|0|_0()) -> s_1(|0|_0()) r20: fact_1(s_1(x)) -> *_2(s_1(x),fact_1(p_1(s_1(x)))) r21: *_2(|0|_0(),y) -> |0|_0() r22: *_2(s_1(x),y) -> +_2(*_2(x,y),y) r23: +_2(x,|0|_0()) -> x r24: +_2(x,s_1(y)) -> s_1(+_2(x,y)) r25: map_2(f,nil_0()) -> nil_0() r26: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r27: filter_2(f,nil_0()) -> nil_0() r28: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r29: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r30: 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: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: +_2#_A(x1,x2) = x2 s_1_A(x1) = x1 + 4 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: +_2#_A(x1,x2) = 0 s_1_A(x1) = max{12, x1 - 5} +_2#!_A(x1,x2) = max{1, x2 - 41} s_1!_A(x1) = max{5, x1 - 40} partial status: pi(+_2#) = [] pi(s_1) = [1] The following rules are removed: p1 Then no dependency pair remains.