YES We show the termination of the TRS R: app(f(),|0|()) -> true() app(f(),|1|()) -> false() app(f(),app(s(),x)) -> app(f(),x) app(app(app(if(),true()),app(s(),x)),app(s(),y)) -> app(s(),x) app(app(app(if(),false()),app(s(),x)),app(s(),y)) -> app(s(),y) app(app(g(),x),app(c(),y)) -> app(c(),app(app(g(),x),y)) app(app(g(),x),app(c(),y)) -> app(app(g(),x),app(app(app(if(),app(f(),x)),app(c(),app(app(g(),app(s(),x)),y))),app(c(),y))) 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(c_0(),y) -> c_1(y) 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(g_1(x1),y) -> g_2(x1,y) app(if_0(),y) -> if_1(y) app(if_1(x1),y) -> if_2(x1,y) app(if_2(x1,x2),y) -> if_3(x1,x2,y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) app(s_0(),y) -> s_1(y) f_1(|0|_0()) -> true_0() f_1(|1|_0()) -> false_0() f_1(s_1(x)) -> f_1(x) if_3(true_0(),s_1(x),s_1(y)) -> s_1(x) if_3(false_0(),s_1(x),s_1(y)) -> s_1(y) g_2(x,c_1(y)) -> c_1(g_2(x,y)) g_2(x,c_1(y)) -> g_2(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) 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#(g_1(x1),y) -> g_2#(x1,y) p5: app#(if_2(x1,x2),y) -> if_3#(x1,x2,y) p6: app#(map_1(x1),y) -> map_2#(x1,y) p7: f_1#(s_1(x)) -> f_1#(x) p8: g_2#(x,c_1(y)) -> g_2#(x,y) p9: g_2#(x,c_1(y)) -> g_2#(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) p10: g_2#(x,c_1(y)) -> if_3#(f_1(x),c_1(g_2(s_1(x),y)),c_1(y)) p11: g_2#(x,c_1(y)) -> f_1#(x) p12: g_2#(x,c_1(y)) -> g_2#(s_1(x),y) p13: map_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p14: map_2#(|fun|,cons_2(x,xs)) -> map_2#(|fun|,xs) p15: filter_2#(|fun|,cons_2(x,xs)) -> filter2_4#(app(|fun|,x),|fun|,x,xs) p16: filter_2#(|fun|,cons_2(x,xs)) -> app#(|fun|,x) p17: filter2_4#(true_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) p18: filter2_4#(false_0(),|fun|,x,xs) -> filter_2#(|fun|,xs) and R consists of: r1: app(c_0(),y) -> c_1(y) r2: app(cons_0(),y) -> cons_1(y) r3: app(cons_1(x1),y) -> cons_2(x1,y) r4: app(f_0(),y) -> f_1(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(g_0(),y) -> g_1(y) r12: app(g_1(x1),y) -> g_2(x1,y) r13: app(if_0(),y) -> if_1(y) r14: app(if_1(x1),y) -> if_2(x1,y) r15: app(if_2(x1,x2),y) -> if_3(x1,x2,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: app(s_0(),y) -> s_1(y) r19: f_1(|0|_0()) -> true_0() r20: f_1(|1|_0()) -> false_0() r21: f_1(s_1(x)) -> f_1(x) r22: if_3(true_0(),s_1(x),s_1(y)) -> s_1(x) r23: if_3(false_0(),s_1(x),s_1(y)) -> s_1(y) r24: g_2(x,c_1(y)) -> c_1(g_2(x,y)) r25: g_2(x,c_1(y)) -> g_2(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) r26: map_2(|fun|,nil_0()) -> nil_0() r27: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r28: filter_2(|fun|,nil_0()) -> nil_0() r29: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r30: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r31: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The estimated dependency graph contains the following SCCs: {p2, p3, p6, p13, p14, p15, p16, p17, p18} {p8, p12} {p7} -- 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(c_0(),y) -> c_1(y) r2: app(cons_0(),y) -> cons_1(y) r3: app(cons_1(x1),y) -> cons_2(x1,y) r4: app(f_0(),y) -> f_1(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(g_0(),y) -> g_1(y) r12: app(g_1(x1),y) -> g_2(x1,y) r13: app(if_0(),y) -> if_1(y) r14: app(if_1(x1),y) -> if_2(x1,y) r15: app(if_2(x1,x2),y) -> if_3(x1,x2,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: app(s_0(),y) -> s_1(y) r19: f_1(|0|_0()) -> true_0() r20: f_1(|1|_0()) -> false_0() r21: f_1(s_1(x)) -> f_1(x) r22: if_3(true_0(),s_1(x),s_1(y)) -> s_1(x) r23: if_3(false_0(),s_1(x),s_1(y)) -> s_1(y) r24: g_2(x,c_1(y)) -> c_1(g_2(x,y)) r25: g_2(x,c_1(y)) -> g_2(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) r26: map_2(|fun|,nil_0()) -> nil_0() r27: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r28: filter_2(|fun|,nil_0()) -> nil_0() r29: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r30: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r31: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r1, r13, r18, r22, r23, r26 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{3, x1 - 4, x2 - 3} cons_2_A(x1,x2) = max{x1 + 4, x2 + 5} app#_A(x1,x2) = max{3, x1 - 16, x2 - 1} map_1_A(x1) = x1 + 12 filter2_3_A(x1,x2,x3) = max{17, x2 + 12, x3 + 12} filter2_4#_A(x1,x2,x3,x4) = max{3, x2 - 11, x3 - 4, x4 - 1} false_0_A = 12 filter_2#_A(x1,x2) = max{3, x1 - 11, x2 - 3} filter_1_A(x1) = x1 + 5 app_A(x1,x2) = 12 true_0_A = 12 c_0_A = 12 c_1_A(x1) = 0 if_0_A = 37 if_1_A(x1) = 12 s_0_A = 12 s_1_A(x1) = 1 if_3_A(x1,x2,x3) = 3 map_2_A(x1,x2) = 3 nil_0_A = 2 map_2#!_A(x1,x2) = max{x1 + 12, x2 - 6} cons_2!_A(x1,x2) = max{3, x2 + 1} app#!_A(x1,x2) = max{2, x1, x2 - 3} map_1!_A(x1) = max{1, x1 - 18} filter2_3!_A(x1,x2,x3) = max{3, x1 + 1} filter2_4#!_A(x1,x2,x3,x4) = max{x2 + 5, x3 - 1, x4 - 4} false_0!_A = 15 filter_2#!_A(x1,x2) = max{x1 + 5, x2 - 5} filter_1!_A(x1) = max{6, x1 - 1} app!_A(x1,x2) = max{18, x1 - 16, x2 + 16} true_0!_A = 8 c_0!_A = 2 c_1!_A(x1) = x1 + 14 if_0!_A = 21 if_1!_A(x1) = 20 s_0!_A = 13 s_1!_A(x1) = 14 if_3!_A(x1,x2,x3) = max{20, x1 - 13, x3 - 2} map_2!_A(x1,x2) = max{9, x1 - 17, x2 - 5} nil_0!_A = 8 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{1, x1 - 15, x2 - 19} cons_2_A(x1,x2) = max{x1 + 18, x2 + 5} app#_A(x1,x2) = max{1, x1 - 16, x2 - 18} map_1_A(x1) = max{11, x1 + 1} filter2_3_A(x1,x2,x3) = max{11, x1 - 39, x2 + 1, x3 + 1} filter2_4#_A(x1,x2,x3,x4) = max{1, x2 - 15, x3 - 15, x4 - 18} false_0_A = 11 filter_2#_A(x1,x2) = max{1, x1 - 15, x2 - 18} filter_1_A(x1) = max{15, x1 + 1} app_A(x1,x2) = max{45, x1 - 19, x2 + 11} true_0_A = 11 c_0_A = 13 c_1_A(x1) = max{0, x1 - 1} if_0_A = 13 if_1_A(x1) = max{15, x1 - 1} s_0_A = 13 s_1_A(x1) = x1 + 8 if_3_A(x1,x2,x3) = max{x1 - 39, x2 + 6, x3 + 7} map_2_A(x1,x2) = max{16, x1 + 6, x2 + 11} nil_0_A = 20 map_2#!_A(x1,x2) = x2 + 1 cons_2!_A(x1,x2) = 0 app#!_A(x1,x2) = x2 + 3 map_1!_A(x1) = max{0, x1 - 16} filter2_3!_A(x1,x2,x3) = 0 filter2_4#!_A(x1,x2,x3,x4) = max{2, x4 - 1} false_0!_A = 4 filter_2#!_A(x1,x2) = max{1, x2 - 2} filter_1!_A(x1) = max{0, x1 - 1} app!_A(x1,x2) = max{24, x1 - 14, x2 + 21} true_0!_A = 2 c_0!_A = 1 c_1!_A(x1) = max{0, x1 - 13} if_0!_A = 2 if_1!_A(x1) = 1 s_0!_A = 23 s_1!_A(x1) = max{22, x1 - 10} if_3!_A(x1,x2,x3) = max{26, x1 - 46, x2 - 9, x3 - 11} map_2!_A(x1,x2) = max{0, x1 - 15, x2 - 21} nil_0!_A = 0 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(c_0) = [] pi(c_1) = [] pi(if_0) = [] pi(if_1) = [1] pi(s_0) = [] pi(s_1) = [] pi(if_3) = [1, 3] pi(map_2) = [1, 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: g_2#(x,c_1(y)) -> g_2#(s_1(x),y) p2: g_2#(x,c_1(y)) -> g_2#(x,y) and R consists of: r1: app(c_0(),y) -> c_1(y) r2: app(cons_0(),y) -> cons_1(y) r3: app(cons_1(x1),y) -> cons_2(x1,y) r4: app(f_0(),y) -> f_1(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(g_0(),y) -> g_1(y) r12: app(g_1(x1),y) -> g_2(x1,y) r13: app(if_0(),y) -> if_1(y) r14: app(if_1(x1),y) -> if_2(x1,y) r15: app(if_2(x1,x2),y) -> if_3(x1,x2,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: app(s_0(),y) -> s_1(y) r19: f_1(|0|_0()) -> true_0() r20: f_1(|1|_0()) -> false_0() r21: f_1(s_1(x)) -> f_1(x) r22: if_3(true_0(),s_1(x),s_1(y)) -> s_1(x) r23: if_3(false_0(),s_1(x),s_1(y)) -> s_1(y) r24: g_2(x,c_1(y)) -> c_1(g_2(x,y)) r25: g_2(x,c_1(y)) -> g_2(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) r26: map_2(|fun|,nil_0()) -> nil_0() r27: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r28: filter_2(|fun|,nil_0()) -> nil_0() r29: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r30: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r31: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r19, r20 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: g_2#_A(x1,x2) = max{0, x1 - 6, x2 - 17} c_1_A(x1) = max{15, x1 + 8} s_1_A(x1) = max{5, x1 - 1} f_1_A(x1) = max{21, x1 - 1} |0|_0_A = 0 true_0_A = 0 |1|_0_A = 0 false_0_A = 0 g_2#!_A(x1,x2) = max{8, x1 - 6, x2 - 80} c_1!_A(x1) = max{7, x1 - 81} s_1!_A(x1) = max{4, x1 - 89} f_1!_A(x1) = max{2, x1 - 89} |0|_0!_A = 0 true_0!_A = 1 |1|_0!_A = 0 false_0!_A = 1 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: g_2#_A(x1,x2) = max{0, x1 - 4, x2 - 20} c_1_A(x1) = max{18, x1 + 13} s_1_A(x1) = max{3, x1 - 1} f_1_A(x1) = max{20, x1 - 2} |0|_0_A = 0 true_0_A = 0 |1|_0_A = 0 false_0_A = 0 g_2#!_A(x1,x2) = max{8, x1 - 4, x2 - 51} c_1!_A(x1) = max{0, x1 - 50} s_1!_A(x1) = max{7, x1 - 81} f_1!_A(x1) = max{7, x1 - 81} |0|_0!_A = 0 true_0!_A = 6 |1|_0!_A = 7 false_0!_A = 6 partial status: pi(g_2#) = [2] pi(c_1) = [1] pi(s_1) = [] pi(f_1) = [] pi(|0|_0) = [] pi(true_0) = [] pi(|1|_0) = [] pi(false_0) = [] 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: f_1#(s_1(x)) -> f_1#(x) and R consists of: r1: app(c_0(),y) -> c_1(y) r2: app(cons_0(),y) -> cons_1(y) r3: app(cons_1(x1),y) -> cons_2(x1,y) r4: app(f_0(),y) -> f_1(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(g_0(),y) -> g_1(y) r12: app(g_1(x1),y) -> g_2(x1,y) r13: app(if_0(),y) -> if_1(y) r14: app(if_1(x1),y) -> if_2(x1,y) r15: app(if_2(x1,x2),y) -> if_3(x1,x2,y) r16: app(map_0(),y) -> map_1(y) r17: app(map_1(x1),y) -> map_2(x1,y) r18: app(s_0(),y) -> s_1(y) r19: f_1(|0|_0()) -> true_0() r20: f_1(|1|_0()) -> false_0() r21: f_1(s_1(x)) -> f_1(x) r22: if_3(true_0(),s_1(x),s_1(y)) -> s_1(x) r23: if_3(false_0(),s_1(x),s_1(y)) -> s_1(y) r24: g_2(x,c_1(y)) -> c_1(g_2(x,y)) r25: g_2(x,c_1(y)) -> g_2(x,if_3(f_1(x),c_1(g_2(s_1(x),y)),c_1(y))) r26: map_2(|fun|,nil_0()) -> nil_0() r27: map_2(|fun|,cons_2(x,xs)) -> cons_2(app(|fun|,x),map_2(|fun|,xs)) r28: filter_2(|fun|,nil_0()) -> nil_0() r29: filter_2(|fun|,cons_2(x,xs)) -> filter2_4(app(|fun|,x),|fun|,x,xs) r30: filter2_4(true_0(),|fun|,x,xs) -> cons_2(x,filter_2(|fun|,xs)) r31: filter2_4(false_0(),|fun|,x,xs) -> filter_2(|fun|,xs) The set of usable rules consists of r19, r20 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) = x1 s_1_A(x1) = max{3, x1 + 1} f_1_A(x1) = max{16, x1 - 49} |0|_0_A = 48 true_0_A = 6 |1|_0_A = 48 false_0_A = 0 f_1#!_A(x1) = max{4, x1 - 47} s_1!_A(x1) = max{4, x1 - 46} f_1!_A(x1) = max{3, x1 - 45} |0|_0!_A = 3 true_0!_A = 2 |1|_0!_A = 3 false_0!_A = 2 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f_1#_A(x1) = x1 s_1_A(x1) = x1 + 17 f_1_A(x1) = max{22, x1 - 7} |0|_0_A = 0 true_0_A = 0 |1|_0_A = 6 false_0_A = 0 f_1#!_A(x1) = max{1, x1 - 87} s_1!_A(x1) = max{8, x1 - 87} f_1!_A(x1) = max{4, x1 - 86} |0|_0!_A = 6 true_0!_A = 5 |1|_0!_A = 4 false_0!_A = 3 partial status: pi(f_1#) = [1] pi(s_1) = [1] pi(f_1) = [] pi(|0|_0) = [] pi(true_0) = [] pi(|1|_0) = [] pi(false_0) = [] The following rules are removed: p1 Then no dependency pair remains.