YES We show the termination of the TRS R: minus(x,|0|()) -> x minus(s(x),s(y)) -> minus(x,y) quot(|0|(),s(y)) -> |0|() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) plus(|0|(),y) -> y plus(s(x),y) -> s(plus(x,y)) minus(minus(x,y),z) -> minus(x,plus(y,z)) app(nil(),k) -> k app(l,nil()) -> l app(cons(x,l),k) -> cons(x,app(l,k)) sum(cons(x,nil())) -> cons(x,nil()) sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) p2: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) p3: quot#(s(x),s(y)) -> minus#(x,y) p4: plus#(s(x),y) -> plus#(x,y) p5: minus#(minus(x,y),z) -> minus#(x,plus(y,z)) p6: minus#(minus(x,y),z) -> plus#(y,z) p7: app#(cons(x,l),k) -> app#(l,k) p8: sum#(cons(x,cons(y,l))) -> sum#(cons(plus(x,y),l)) p9: sum#(cons(x,cons(y,l))) -> plus#(x,y) p10: sum#(app(l,cons(x,cons(y,k)))) -> sum#(app(l,sum(cons(x,cons(y,k))))) p11: sum#(app(l,cons(x,cons(y,k)))) -> app#(l,sum(cons(x,cons(y,k)))) p12: sum#(app(l,cons(x,cons(y,k)))) -> sum#(cons(x,cons(y,k))) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) The estimated dependency graph contains the following SCCs: {p2} {p1, p5} {p10} {p8} {p4} {p7} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) The set of usable rules consists of r1, r2, r5, r6, r7 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: quot#_A(x1,x2) = x2 s_A(x1) = max{5, x1} minus_A(x1,x2) = max{x1 + 5, x2 - 6} |0|_A = 2 plus_A(x1,x2) = max{x1, x2} quot#!_A(x1,x2) = 0 s!_A(x1) = 3 minus!_A(x1,x2) = 0 |0|!_A = 5 plus!_A(x1,x2) = max{29, x1 - 4, x2 + 2} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: quot#_A(x1,x2) = max{0, x1 - 8, x2 - 6} s_A(x1) = max{4, x1} minus_A(x1,x2) = max{7, x1, x2 - 46} |0|_A = 8 plus_A(x1,x2) = max{4, x1 - 56, x2} quot#!_A(x1,x2) = 0 s!_A(x1) = max{1, x1 - 10} minus!_A(x1,x2) = max{2, x1 - 19, x2 - 9} |0|!_A = 2 plus!_A(x1,x2) = max{52, x1 - 5, x2 - 5} partial status: pi(quot#) = [1] pi(s) = [1] pi(minus) = [1] pi(|0|) = [] pi(plus) = [1, 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: minus#(s(x),s(y)) -> minus#(x,y) p2: minus#(minus(x,y),z) -> minus#(x,plus(y,z)) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) The set of usable rules consists of r1, r5, r6 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: minus#_A(x1,x2) = max{0, x1 - 6, x2 - 4} s_A(x1) = max{2, x1} minus_A(x1,x2) = max{4, x1 + 1, x2 - 4} plus_A(x1,x2) = max{3, x1 - 6, x2} |0|_A = 2 minus#!_A(x1,x2) = max{3, x1 - 6, x2 - 4} s!_A(x1) = max{2, x1 - 18} minus!_A(x1,x2) = max{5, x1 - 7, x2 - 13} plus!_A(x1,x2) = max{4, x1 - 12, x2 - 14} |0|!_A = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: minus#_A(x1,x2) = max{0, x1 - 25, x2 - 32} s_A(x1) = max{21, x1} minus_A(x1,x2) = max{23, x1 + 1, x2 - 32} plus_A(x1,x2) = max{31, x1 - 33, x2} |0|_A = 3 minus#!_A(x1,x2) = max{1, x1 - 28, x2 - 35} s!_A(x1) = max{2, x1 - 71} minus!_A(x1,x2) = max{4, x1 - 29, x2 - 69} plus!_A(x1,x2) = max{3, x1 - 62, x2 - 70} |0|!_A = 2 partial status: pi(minus#) = [1] pi(s) = [1] pi(minus) = [1, 2] pi(plus) = [1, 2] pi(|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: sum#(app(l,cons(x,cons(y,k)))) -> sum#(app(l,sum(cons(x,cons(y,k))))) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) The set of usable rules consists of r5, r6, r8, r9, r10, r11, r12, r13 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: sum#_A(x1) = max{62, x1} app_A(x1,x2) = max{x1 + 70, x2} cons_A(x1,x2) = 62 sum_A(x1) = max{2, x1} plus_A(x1,x2) = max{25, x1 - 70, x2 + 12} |0|_A = 13 s_A(x1) = max{13, x1 - 26} nil_A = 61 sum#!_A(x1) = 0 app!_A(x1,x2) = x2 cons!_A(x1,x2) = 0 sum!_A(x1) = max{0, x1 - 62} plus!_A(x1,x2) = max{x1 - 14, x2 + 55} |0|!_A = 30 s!_A(x1) = x1 + 29 nil!_A = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: sum#_A(x1) = max{14, x1 - 30} app_A(x1,x2) = max{x1 + 29, x2 + 16} cons_A(x1,x2) = max{29, x1 + 13, x2} sum_A(x1) = max{13, x1} plus_A(x1,x2) = max{14, x2} |0|_A = 5 s_A(x1) = max{4, x1 - 15} nil_A = 1 sum#!_A(x1) = x1 + 3 app!_A(x1,x2) = max{63, x1 + 34, x2 + 31} cons!_A(x1,x2) = x2 + 4 sum!_A(x1) = 6 plus!_A(x1,x2) = max{3, x1 - 14, x2 - 10} |0|!_A = 1 s!_A(x1) = max{0, x1 - 23} nil!_A = 1 partial status: pi(sum#) = [1] pi(app) = [1, 2] pi(cons) = [] pi(sum) = [] pi(plus) = [2] pi(|0|) = [] pi(s) = [] pi(nil) = [] 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#(cons(x,cons(y,l))) -> sum#(cons(plus(x,y),l)) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) The set of usable rules consists of r5, r6 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: sum#_A(x1) = max{0, x1 - 15} cons_A(x1,x2) = max{x1 - 13, x2 + 3} plus_A(x1,x2) = max{27, x1 - 43, x2 + 2} |0|_A = 3 s_A(x1) = max{3, x1 - 46} sum#!_A(x1) = max{30, x1 - 7} cons!_A(x1,x2) = max{x1 + 4, x2 + 45} plus!_A(x1,x2) = max{3, x1 - 51, x2 - 52} |0|!_A = 3 s!_A(x1) = max{1, x1 - 54} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: sum#_A(x1) = max{0, x1 - 23} cons_A(x1,x2) = max{x1 - 60, x2 + 8} plus_A(x1,x2) = max{82, x1 - 72, x2 + 5} |0|_A = 92 s_A(x1) = max{6, x1 - 83} sum#!_A(x1) = max{3, x1 - 276} cons!_A(x1,x2) = max{3, x1 - 332, x2 - 270} plus!_A(x1,x2) = max{4, x1 - 165, x2 - 250} |0|!_A = 2 s!_A(x1) = max{1, x1 - 331} partial status: pi(sum#) = [1] pi(cons) = [1, 2] pi(plus) = [1, 2] pi(|0|) = [] pi(s) = [] 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#(s(x),y) -> plus#(x,y) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) 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: plus#_A(x1,x2) = max{0, x1 - 6} s_A(x1) = max{16, x1 + 5} plus#!_A(x1,x2) = max{2, x1 - 6} s!_A(x1) = max{1, x1 - 76} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: plus#_A(x1,x2) = max{0, x1 - 4} s_A(x1) = max{17, x1 + 3} plus#!_A(x1,x2) = max{1, x1 - 78, x2 - 1} s!_A(x1) = max{0, x1 - 78} partial status: pi(plus#) = [] pi(s) = [] 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: app#(cons(x,l),k) -> app#(l,k) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) r8: app(nil(),k) -> k r9: app(l,nil()) -> l r10: app(cons(x,l),k) -> cons(x,app(l,k)) r11: sum(cons(x,nil())) -> cons(x,nil()) r12: sum(cons(x,cons(y,l))) -> sum(cons(plus(x,y),l)) r13: sum(app(l,cons(x,cons(y,k)))) -> sum(app(l,sum(cons(x,cons(y,k))))) 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: app#_A(x1,x2) = max{0, x1 - 5} cons_A(x1,x2) = max{x1 - 40, x2 + 4} app#!_A(x1,x2) = max{4, x1 - 296, x2 - 1} cons!_A(x1,x2) = max{3, x1 - 339, x2 - 297} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{0, x1 - 5} cons_A(x1,x2) = max{24, x1 - 12, x2 + 4} app#!_A(x1,x2) = max{4, x1 - 134, x2 - 1} cons!_A(x1,x2) = max{3, x1 - 239, x2 - 133} partial status: pi(app#) = [1] pi(cons) = [1, 2] The following rules are removed: p1 Then no dependency pair remains.