YES We show the termination of the TRS R: 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(sum(),app(app(cons(),x),xs)) -> app(app(plus(),x),app(sum(),xs)) app(size(),app(app(node(),x),xs)) -> app(s(),app(sum(),app(app(map(),size()),xs))) app(app(plus(),|0|()),x) -> |0|() app(app(plus(),app(s(),x)),y) -> app(s(),app(app(plus(),x),y)) Instead we prove termination of the uncurried system: app(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) app(node_0(),y) -> node_1(y) app(node_1(x1),y) -> node_2(x1,y) app(plus_0(),y) -> plus_1(y) app(plus_1(x1),y) -> plus_2(x1,y) app(s_0(),y) -> s_1(y) app(size_0(),y) -> size_1(y) app(sum_0(),y) -> sum_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)) sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) plus_2(|0|_0(),x) -> |0|_0() plus_2(s_1(x),y) -> s_1(plus_2(x,y)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(map_1(x1),y) -> map_2#(x1,y) p2: app#(plus_1(x1),y) -> plus_2#(x1,y) p3: app#(size_0(),y) -> size_1#(y) p4: app#(sum_0(),y) -> sum_1#(y) p5: map_2#(f,cons_2(x,xs)) -> app#(f,x) p6: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p7: sum_1#(cons_2(x,xs)) -> plus_2#(x,sum_1(xs)) p8: sum_1#(cons_2(x,xs)) -> sum_1#(xs) p9: size_1#(node_2(x,xs)) -> sum_1#(map_2(size_0(),xs)) p10: size_1#(node_2(x,xs)) -> map_2#(size_0(),xs) p11: plus_2#(s_1(x),y) -> plus_2#(x,y) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) The estimated dependency graph contains the following SCCs: {p1, p3, p5, p6, p10} {p8} {p11} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(map_1(x1),y) -> map_2#(x1,y) p2: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p3: map_2#(f,cons_2(x,xs)) -> app#(f,x) p4: app#(size_0(),y) -> size_1#(y) p5: size_1#(node_2(x,xs)) -> map_2#(size_0(),xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) 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!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: app#_A(x1,x2) = x2 map_1_A(x1) = x1 + 3 map_2#_A(x1,x2) = x2 cons_2_A(x1,x2) = x1 + x2 + 5 size_0_A() = 1 size_1#_A(x1) = x1 node_2_A(x1,x2) = x2 + 5 app#!_A(x1,x2) = 15 map_1!_A(x1) = 4 map_2#!_A(x1,x2) = 14 cons_2!_A(x1,x2) = x2 + 16 size_0!_A() = 12 size_1#!_A(x1) = 13 node_2!_A(x1,x2) = 15 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: app#_A(x1,x2) = x2 map_1_A(x1) = x1 + 3 map_2#_A(x1,x2) = x2 cons_2_A(x1,x2) = x1 + x2 + 16 size_0_A() = 1 size_1#_A(x1) = x1 node_2_A(x1,x2) = x2 + 5 app#!_A(x1,x2) = 9 map_1!_A(x1) = 3 map_2#!_A(x1,x2) = 2 cons_2!_A(x1,x2) = x2 + 10 size_0!_A() = 2 size_1#!_A(x1) = 1 node_2!_A(x1,x2) = 8 partial status: pi(app#) = [2] pi(map_1) = [1] pi(map_2#) = [2] pi(cons_2) = [1, 2] pi(size_0) = [] pi(size_1#) = [1] pi(node_2) = [2] The following rules are removed: p1, p3, p4, p5 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) The set of usable rules consists of r3 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!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: map_2#_A(x1,x2) = x2 cons_2_A(x1,x2) = x1 + x2 + 5 app_A(x1,x2) = x1 + x2 + 1 map_0_A() = 1 map_1_A(x1) = x1 + 1 map_2#!_A(x1,x2) = x2 + 2 cons_2!_A(x1,x2) = 1 app!_A(x1,x2) = x2 + 5 map_0!_A() = 0 map_1!_A(x1) = 1 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) = x2 cons_2_A(x1,x2) = x2 + 5 app_A(x1,x2) = 1 map_0_A() = 1 map_1_A(x1) = 1 map_2#!_A(x1,x2) = x2 cons_2!_A(x1,x2) = x1 + x2 + 3 app!_A(x1,x2) = 9 map_0!_A() = 0 map_1!_A(x1) = 1 partial status: pi(map_2#) = [] pi(cons_2) = [] pi(app) = [1, 2] pi(map_0) = [] pi(map_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: sum_1#(cons_2(x,xs)) -> sum_1#(xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) 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!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: sum_1#_A(x1) = x1 cons_2_A(x1,x2) = x1 + x2 + 5 sum_1#!_A(x1) = x1 + 8 cons_2!_A(x1,x2) = x1 + 7 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: sum_1#_A(x1) = x1 cons_2_A(x1,x2) = x2 + 2 sum_1#!_A(x1) = x1 + 5 cons_2!_A(x1,x2) = x1 + 4 partial status: pi(sum_1#) = [] pi(cons_2) = [2] 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: plus_2#(s_1(x),y) -> plus_2#(x,y) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(node_0(),y) -> node_1(y) r6: app(node_1(x1),y) -> node_2(x1,y) r7: app(plus_0(),y) -> plus_1(y) r8: app(plus_1(x1),y) -> plus_2(x1,y) r9: app(s_0(),y) -> s_1(y) r10: app(size_0(),y) -> size_1(y) r11: app(sum_0(),y) -> sum_1(y) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r14: sum_1(cons_2(x,xs)) -> plus_2(x,sum_1(xs)) r15: size_1(node_2(x,xs)) -> s_1(sum_1(map_2(size_0(),xs))) r16: plus_2(|0|_0(),x) -> |0|_0() r17: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) 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!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: plus_2#_A(x1,x2) = x1 s_1_A(x1) = x1 + 2 plus_2#!_A(x1,x2) = x1 + 2 s_1!_A(x1) = x1 + 1 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: plus_2#_A(x1,x2) = x1 s_1_A(x1) = x1 + 2 plus_2#!_A(x1,x2) = x1 s_1!_A(x1) = x1 + 1 partial status: pi(plus_2#) = [2] pi(s_1) = [] The following rules are removed: p1 Then no dependency pair remains.