YES We show the termination of the TRS R: app(app(.(),|1|()),x) -> x app(app(.(),x),|1|()) -> x app(app(.(),app(i(),x)),x) -> |1|() app(app(.(),x),app(i(),x)) -> |1|() app(app(.(),app(i(),y)),app(app(.(),y),z)) -> z app(app(.(),y),app(app(.(),app(i(),y)),z)) -> z app(app(.(),app(app(.(),x),y)),z) -> app(app(.(),x),app(app(.(),y),z)) app(i(),|1|()) -> |1|() app(i(),app(i(),x)) -> x app(i(),app(app(.(),x),y)) -> app(app(.(),app(i(),y)),app(i(),x)) 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(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(i_0(),y) -> i_1(y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) ._2(|1|_0(),x) -> x ._2(x,|1|_0()) -> x ._2(i_1(x),x) -> |1|_0() ._2(x,i_1(x)) -> |1|_0() ._2(i_1(y),._2(y,z)) -> z ._2(y,._2(i_1(y),z)) -> z ._2(._2(x,y),z) -> ._2(x,._2(y,z)) i_1(|1|_0()) -> |1|_0() i_1(i_1(x)) -> x i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) 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#(filter_1(x1),y) -> filter_2#(x1,y) p3: app#(filter2_3(x1,x2,x3),y) -> filter2_4#(x1,x2,x3,y) p4: app#(i_0(),y) -> i_1#(y) p5: app#(map_1(x1),y) -> map_2#(x1,y) p6: ._2#(._2(x,y),z) -> ._2#(x,._2(y,z)) p7: ._2#(._2(x,y),z) -> ._2#(y,z) p8: i_1#(._2(x,y)) -> ._2#(i_1(y),i_1(x)) p9: i_1#(._2(x,y)) -> i_1#(y) p10: i_1#(._2(x,y)) -> i_1#(x) 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(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The estimated dependency graph contains the following SCCs: {p2, p3, p5, p11, p12, p13, p14, p15, p16} {p9, p10} {p6, p7} -- 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(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The set of usable rules consists of r14, r15, r18, r19, r21, r26 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) = 4 cons_2_A(x1,x2) = 5 app#_A(x1,x2) = 4 map_1_A(x1) = x1 + 5 filter2_3_A(x1,x2,x3) = x2 + x3 + 7 filter2_4#_A(x1,x2,x3,x4) = 4 false_0_A() = 5 filter_2#_A(x1,x2) = 4 filter_1_A(x1) = x1 + 5 app_A(x1,x2) = x1 + x2 + 3 true_0_A() = 6 ._2_A(x1,x2) = x1 + x2 + 3 |1|_0_A() = 1 i_1_A(x1) = 2 filter_2_A(x1,x2) = 2 nil_0_A() = 1 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{1, x1 - 25, x2 - 98} cons_2_A(x1,x2) = max{97, x1 + 64, x2 + 88} app#_A(x1,x2) = max{1, x1 - 26, x2 - 98} map_1_A(x1) = max{17, x1 + 1} filter2_3_A(x1,x2,x3) = max{x1 + 1, x2 + 1, x3 + 25} filter2_4#_A(x1,x2,x3,x4) = max{1, x2 - 26, x3 - 34, x4 - 98} false_0_A = 21 filter_2#_A(x1,x2) = max{1, x1 - 26, x2 - 98} filter_1_A(x1) = max{17, x1 + 1} app_A(x1,x2) = max{16, x1 - 24} true_0_A = 1 ._2_A(x1,x2) = max{17, x1, x2} |1|_0_A = 20 i_1_A(x1) = max{19, x1 + 1} filter_2_A(x1,x2) = max{22, x1 - 47, x2 + 1} nil_0_A = 87 map_2#!_A(x1,x2) = max{18, x2 - 44} cons_2!_A(x1,x2) = max{15, x1, x2 - 43} app#!_A(x1,x2) = x2 + 19 map_1!_A(x1) = max{2, x1 - 26} filter2_3!_A(x1,x2,x3) = max{2, x1 - 24} filter2_4#!_A(x1,x2,x3,x4) = max{16, x4 + 11} false_0!_A = 11 filter_2#!_A(x1,x2) = max{10, x2 - 39} filter_1!_A(x1) = max{9, x1 - 19} app!_A(x1,x2) = max{x1 - 18, x2 + 9} true_0!_A = 1 ._2!_A(x1,x2) = max{4, x1 - 21} |1|_0!_A = 1 i_1!_A(x1) = max{4, x1 - 21} filter_2!_A(x1,x2) = max{12, x1 - 19, x2 - 88} nil_0!_A = 13 partial status: pi(map_2#) = [] pi(cons_2) = [] pi(app#) = [] pi(map_1) = [1] pi(filter2_3) = [3] pi(filter2_4#) = [] pi(false_0) = [] pi(filter_2#) = [] pi(filter_1) = [] pi(app) = [2] pi(true_0) = [] pi(._2) = [] pi(|1|_0) = [] pi(i_1) = [] pi(filter_2) = [] 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: i_1#(._2(x,y)) -> i_1#(x) p2: i_1#(._2(x,y)) -> i_1#(y) and R consists of: r1: app(._0(),y) -> ._1(y) r2: app(._1(x1),y) -> ._2(x1,y) r3: app(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: 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: i_1#_A(x1) = x1 ._2_A(x1,x2) = x1 + x2 + 3 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: i_1#_A(x1) = 0 ._2_A(x1,x2) = max{6, x1 - 7, x2 - 8} i_1#!_A(x1) = max{6, x1 - 27} ._2!_A(x1,x2) = max{5, x1 - 26, x2 - 15} partial status: pi(i_1#) = [1] pi(._2) = [] The following rules are removed: p1, p2 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: ._2#(._2(x,y),z) -> ._2#(x,._2(y,z)) p2: ._2#(._2(x,y),z) -> ._2#(y,z) and R consists of: r1: app(._0(),y) -> ._1(y) r2: app(._1(x1),y) -> ._2(x1,y) r3: app(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The set of usable rules consists of r14, r15, r16, r17, r18, r19, r20 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 + x2 + 1 ._2_A(x1,x2) = x1 + x2 + 4 |1|_0_A() = 1 i_1_A(x1) = 2 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: ._2#_A(x1,x2) = max{0, x1 - 11, x2 - 21} ._2_A(x1,x2) = max{x1 + 10, x2} |1|_0_A = 10 i_1_A(x1) = max{2, x1 - 11} ._2#!_A(x1,x2) = max{5, x1 - 5, x2 - 15} ._2!_A(x1,x2) = max{4, x1 - 11, x2 - 23} |1|_0!_A = 0 i_1!_A(x1) = max{4, x1 - 11} partial status: pi(._2#) = [1] pi(._2) = [] pi(|1|_0) = [] pi(i_1) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: ._2#(._2(x,y),z) -> ._2#(x,._2(y,z)) and R consists of: r1: app(._0(),y) -> ._1(y) r2: app(._1(x1),y) -> ._2(x1,y) r3: app(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: ._2#(._2(x,y),z) -> ._2#(x,._2(y,z)) and R consists of: r1: app(._0(),y) -> ._1(y) r2: app(._1(x1),y) -> ._2(x1,y) r3: app(cons_0(),y) -> cons_1(y) r4: app(cons_1(x1),y) -> cons_2(x1,y) r5: app(filter_0(),y) -> filter_1(y) r6: app(filter_1(x1),y) -> filter_2(x1,y) r7: app(filter2_0(),y) -> filter2_1(y) r8: app(filter2_1(x1),y) -> filter2_2(x1,y) r9: app(filter2_2(x1,x2),y) -> filter2_3(x1,x2,y) r10: app(filter2_3(x1,x2,x3),y) -> filter2_4(x1,x2,x3,y) r11: app(i_0(),y) -> i_1(y) r12: app(map_0(),y) -> map_1(y) r13: app(map_1(x1),y) -> map_2(x1,y) r14: ._2(|1|_0(),x) -> x r15: ._2(x,|1|_0()) -> x r16: ._2(i_1(x),x) -> |1|_0() r17: ._2(x,i_1(x)) -> |1|_0() r18: ._2(i_1(y),._2(y,z)) -> z r19: ._2(y,._2(i_1(y),z)) -> z r20: ._2(._2(x,y),z) -> ._2(x,._2(y,z)) r21: i_1(|1|_0()) -> |1|_0() r22: i_1(i_1(x)) -> x r23: i_1(._2(x,y)) -> ._2(i_1(y),i_1(x)) r24: map_2(f,nil_0()) -> nil_0() r25: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r26: filter_2(f,nil_0()) -> nil_0() r27: filter_2(f,cons_2(x,xs)) -> filter2_4(app(f,x),f,x,xs) r28: filter2_4(true_0(),f,x,xs) -> cons_2(x,filter_2(f,xs)) r29: filter2_4(false_0(),f,x,xs) -> filter_2(f,xs) The set of usable rules consists of r14, r15, r16, r17, r18, r19, r20 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 + x2 + 1 ._2_A(x1,x2) = x1 + x2 + 4 |1|_0_A() = 1 i_1_A(x1) = 2 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: ._2#_A(x1,x2) = max{0, x1 - 5, x2 - 6} ._2_A(x1,x2) = max{4, x1 + 1, x2} |1|_0_A = 4 i_1_A(x1) = max{2, x1 - 59} ._2#!_A(x1,x2) = max{5, x1 - 84, x2 - 85} ._2!_A(x1,x2) = max{4, x1 - 83, x2 - 88} |1|_0!_A = 0 i_1!_A(x1) = max{2, x1 - 91} partial status: pi(._2#) = [1] pi(._2) = [1] pi(|1|_0) = [] pi(i_1) = [] The following rules are removed: p1 Then no dependency pair remains.