YES We show the termination of the TRS R: +(x,|0|()) -> x +(|0|(),x) -> x +(s(x),s(y)) -> s(s(+(x,y))) *(x,|0|()) -> |0|() *(|0|(),x) -> |0|() *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) sum(nil()) -> |0|() sum(cons(x,l)) -> +(x,sum(l)) prod(nil()) -> s(|0|()) prod(cons(x,l)) -> *(x,prod(l)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: +#(s(x),s(y)) -> +#(x,y) p2: *#(s(x),s(y)) -> +#(*(x,y),+(x,y)) p3: *#(s(x),s(y)) -> *#(x,y) p4: *#(s(x),s(y)) -> +#(x,y) p5: sum#(cons(x,l)) -> +#(x,sum(l)) p6: sum#(cons(x,l)) -> sum#(l) p7: prod#(cons(x,l)) -> *#(x,prod(l)) p8: prod#(cons(x,l)) -> prod#(l) and R consists of: r1: +(x,|0|()) -> x r2: +(|0|(),x) -> x r3: +(s(x),s(y)) -> s(s(+(x,y))) r4: *(x,|0|()) -> |0|() r5: *(|0|(),x) -> |0|() r6: *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) r7: sum(nil()) -> |0|() r8: sum(cons(x,l)) -> +(x,sum(l)) r9: prod(nil()) -> s(|0|()) r10: prod(cons(x,l)) -> *(x,prod(l)) The estimated dependency graph contains the following SCCs: {p6} {p8} {p3} {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: sum#(cons(x,l)) -> sum#(l) and R consists of: r1: +(x,|0|()) -> x r2: +(|0|(),x) -> x r3: +(s(x),s(y)) -> s(s(+(x,y))) r4: *(x,|0|()) -> |0|() r5: *(|0|(),x) -> |0|() r6: *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) r7: sum(nil()) -> |0|() r8: sum(cons(x,l)) -> +(x,sum(l)) r9: prod(nil()) -> s(|0|()) r10: prod(cons(x,l)) -> *(x,prod(l)) The set of usable rules consists of r5 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: sum#_A(x1) = 0 cons_A(x1,x2) = max{15, x1 - 2, x2 - 2} *_A(x1,x2) = max{9, x1, x2 - 11} |0|_A = 0 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: sum#_A(x1) = x1 cons_A(x1,x2) = max{12, x1 + 8, x2 + 9} *_A(x1,x2) = max{8, x1 - 5, x2 - 5} |0|_A = 4 sum#!_A(x1) = max{1, x1 - 10} cons!_A(x1,x2) = max{5, x1 - 9, x2 - 9} *!_A(x1,x2) = max{3, x1 - 10, x2 - 5} |0|!_A = 0 partial status: pi(sum#) = [] pi(cons) = [] pi(*) = [] pi(|0|) = [] 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: prod#(cons(x,l)) -> prod#(l) and R consists of: r1: +(x,|0|()) -> x r2: +(|0|(),x) -> x r3: +(s(x),s(y)) -> s(s(+(x,y))) r4: *(x,|0|()) -> |0|() r5: *(|0|(),x) -> |0|() r6: *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) r7: sum(nil()) -> |0|() r8: sum(cons(x,l)) -> +(x,sum(l)) r9: prod(nil()) -> s(|0|()) r10: prod(cons(x,l)) -> *(x,prod(l)) The set of usable rules consists of r5 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: prod#_A(x1) = 0 cons_A(x1,x2) = max{10, x1 - 4, x2 - 4} *_A(x1,x2) = max{4, x1 - 6, x2 - 3} |0|_A = 0 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: prod#_A(x1) = x1 cons_A(x1,x2) = max{10, x1 + 7, x2 + 1} *_A(x1,x2) = max{9, x1 - 5, x2 - 5} |0|_A = 1 prod#!_A(x1) = max{1, x1 - 8} cons!_A(x1,x2) = max{6, x1 - 7, x2 - 7} *!_A(x1,x2) = max{4, x1 - 18, x2 - 2} |0|!_A = 2 partial status: pi(prod#) = [] pi(cons) = [] pi(*) = [] pi(|0|) = [] 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: *#(s(x),s(y)) -> *#(x,y) and R consists of: r1: +(x,|0|()) -> x r2: +(|0|(),x) -> x r3: +(s(x),s(y)) -> s(s(+(x,y))) r4: *(x,|0|()) -> |0|() r5: *(|0|(),x) -> |0|() r6: *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) r7: sum(nil()) -> |0|() r8: sum(cons(x,l)) -> +(x,sum(l)) r9: prod(nil()) -> s(|0|()) r10: prod(cons(x,l)) -> *(x,prod(l)) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: *#_A(x1,x2) = x2 s_A(x1) = x1 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: *#_A(x1,x2) = 0 s_A(x1) = max{26, x1 - 103} *#!_A(x1,x2) = 0 s!_A(x1) = max{52, x1 - 52} partial status: pi(*#) = [2] pi(s) = [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: +#(s(x),s(y)) -> +#(x,y) and R consists of: r1: +(x,|0|()) -> x r2: +(|0|(),x) -> x r3: +(s(x),s(y)) -> s(s(+(x,y))) r4: *(x,|0|()) -> |0|() r5: *(|0|(),x) -> |0|() r6: *(s(x),s(y)) -> s(+(*(x,y),+(x,y))) r7: sum(nil()) -> |0|() r8: sum(cons(x,l)) -> +(x,sum(l)) r9: prod(nil()) -> s(|0|()) r10: prod(cons(x,l)) -> *(x,prod(l)) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: +#_A(x1,x2) = x2 + 7 s_A(x1) = x1 + 7 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: +#_A(x1,x2) = 0 s_A(x1) = max{10, x1 - 53} +#!_A(x1,x2) = 0 s!_A(x1) = max{5, x1 - 25} partial status: pi(+#) = [2] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.