YES We show the termination of the TRS R: a__filter(cons(X,Y),|0|(),M) -> cons(|0|(),filter(Y,M,M)) a__filter(cons(X,Y),s(N),M) -> cons(mark(X),filter(Y,N,M)) a__sieve(cons(|0|(),Y)) -> cons(|0|(),sieve(Y)) a__sieve(cons(s(N),Y)) -> cons(s(mark(N)),sieve(filter(Y,N,N))) a__nats(N) -> cons(mark(N),nats(s(N))) a__zprimes() -> a__sieve(a__nats(s(s(|0|())))) mark(filter(X1,X2,X3)) -> a__filter(mark(X1),mark(X2),mark(X3)) mark(sieve(X)) -> a__sieve(mark(X)) mark(nats(X)) -> a__nats(mark(X)) mark(zprimes()) -> a__zprimes() mark(cons(X1,X2)) -> cons(mark(X1),X2) mark(|0|()) -> |0|() mark(s(X)) -> s(mark(X)) a__filter(X1,X2,X3) -> filter(X1,X2,X3) a__sieve(X) -> sieve(X) a__nats(X) -> nats(X) a__zprimes() -> zprimes() -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: a__filter#(cons(X,Y),s(N),M) -> mark#(X) p2: a__sieve#(cons(s(N),Y)) -> mark#(N) p3: a__nats#(N) -> mark#(N) p4: a__zprimes#() -> a__sieve#(a__nats(s(s(|0|())))) p5: a__zprimes#() -> a__nats#(s(s(|0|()))) p6: mark#(filter(X1,X2,X3)) -> a__filter#(mark(X1),mark(X2),mark(X3)) p7: mark#(filter(X1,X2,X3)) -> mark#(X1) p8: mark#(filter(X1,X2,X3)) -> mark#(X2) p9: mark#(filter(X1,X2,X3)) -> mark#(X3) p10: mark#(sieve(X)) -> a__sieve#(mark(X)) p11: mark#(sieve(X)) -> mark#(X) p12: mark#(nats(X)) -> a__nats#(mark(X)) p13: mark#(nats(X)) -> mark#(X) p14: mark#(zprimes()) -> a__zprimes#() p15: mark#(cons(X1,X2)) -> mark#(X1) p16: mark#(s(X)) -> mark#(X) and R consists of: r1: a__filter(cons(X,Y),|0|(),M) -> cons(|0|(),filter(Y,M,M)) r2: a__filter(cons(X,Y),s(N),M) -> cons(mark(X),filter(Y,N,M)) r3: a__sieve(cons(|0|(),Y)) -> cons(|0|(),sieve(Y)) r4: a__sieve(cons(s(N),Y)) -> cons(s(mark(N)),sieve(filter(Y,N,N))) r5: a__nats(N) -> cons(mark(N),nats(s(N))) r6: a__zprimes() -> a__sieve(a__nats(s(s(|0|())))) r7: mark(filter(X1,X2,X3)) -> a__filter(mark(X1),mark(X2),mark(X3)) r8: mark(sieve(X)) -> a__sieve(mark(X)) r9: mark(nats(X)) -> a__nats(mark(X)) r10: mark(zprimes()) -> a__zprimes() r11: mark(cons(X1,X2)) -> cons(mark(X1),X2) r12: mark(|0|()) -> |0|() r13: mark(s(X)) -> s(mark(X)) r14: a__filter(X1,X2,X3) -> filter(X1,X2,X3) r15: a__sieve(X) -> sieve(X) r16: a__nats(X) -> nats(X) r17: a__zprimes() -> zprimes() The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: a__filter#(cons(X,Y),s(N),M) -> mark#(X) p2: mark#(s(X)) -> mark#(X) p3: mark#(cons(X1,X2)) -> mark#(X1) p4: mark#(zprimes()) -> a__zprimes#() p5: a__zprimes#() -> a__nats#(s(s(|0|()))) p6: a__nats#(N) -> mark#(N) p7: mark#(nats(X)) -> mark#(X) p8: mark#(nats(X)) -> a__nats#(mark(X)) p9: mark#(sieve(X)) -> mark#(X) p10: mark#(sieve(X)) -> a__sieve#(mark(X)) p11: a__sieve#(cons(s(N),Y)) -> mark#(N) p12: mark#(filter(X1,X2,X3)) -> mark#(X3) p13: mark#(filter(X1,X2,X3)) -> mark#(X2) p14: mark#(filter(X1,X2,X3)) -> mark#(X1) p15: mark#(filter(X1,X2,X3)) -> a__filter#(mark(X1),mark(X2),mark(X3)) p16: a__zprimes#() -> a__sieve#(a__nats(s(s(|0|())))) and R consists of: r1: a__filter(cons(X,Y),|0|(),M) -> cons(|0|(),filter(Y,M,M)) r2: a__filter(cons(X,Y),s(N),M) -> cons(mark(X),filter(Y,N,M)) r3: a__sieve(cons(|0|(),Y)) -> cons(|0|(),sieve(Y)) r4: a__sieve(cons(s(N),Y)) -> cons(s(mark(N)),sieve(filter(Y,N,N))) r5: a__nats(N) -> cons(mark(N),nats(s(N))) r6: a__zprimes() -> a__sieve(a__nats(s(s(|0|())))) r7: mark(filter(X1,X2,X3)) -> a__filter(mark(X1),mark(X2),mark(X3)) r8: mark(sieve(X)) -> a__sieve(mark(X)) r9: mark(nats(X)) -> a__nats(mark(X)) r10: mark(zprimes()) -> a__zprimes() r11: mark(cons(X1,X2)) -> cons(mark(X1),X2) r12: mark(|0|()) -> |0|() r13: mark(s(X)) -> s(mark(X)) r14: a__filter(X1,X2,X3) -> filter(X1,X2,X3) r15: a__sieve(X) -> sieve(X) r16: a__nats(X) -> nats(X) r17: a__zprimes() -> zprimes() The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16, r17 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: a__filter#_A(x1,x2,x3) = max{42, x1 + 26, x2 - 16, x3 + 15} cons_A(x1,x2) = x1 + 16 s_A(x1) = max{34, x1 + 33} mark#_A(x1) = x1 + 16 zprimes_A = 123 a__zprimes#_A = 122 a__nats#_A(x1) = max{94, x1 + 18} |0|_A = 9 nats_A(x1) = max{93, x1 + 32} mark_A(x1) = x1 + 15 sieve_A(x1) = x1 + 28 a__sieve#_A(x1) = max{27, x1 + 13} filter_A(x1,x2,x3) = max{x1 + 26, x2, x3 + 26} a__nats_A(x1) = max{108, x1 + 32} a__filter_A(x1,x2,x3) = max{41, x1 + 26, x2, x3 + 26} a__sieve_A(x1) = max{35, x1 + 28} a__zprimes_A = 136 precedence: a__zprimes# = a__nats# = |0| = a__sieve# = a__zprimes > s = zprimes = mark = a__nats = a__filter > cons > a__filter# = mark# = nats = filter = a__sieve > sieve partial status: pi(a__filter#) = [1, 3] pi(cons) = [1] pi(s) = [1] pi(mark#) = [1] pi(zprimes) = [] pi(a__zprimes#) = [] pi(a__nats#) = [1] pi(|0|) = [] pi(nats) = [1] pi(mark) = [1] pi(sieve) = [1] pi(a__sieve#) = [1] pi(filter) = [1, 2, 3] pi(a__nats) = [1] pi(a__filter) = [1, 2, 3] pi(a__sieve) = [1] pi(a__zprimes) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: a__filter#_A(x1,x2,x3) = max{x1 + 89, x3 + 53} cons_A(x1,x2) = x1 + 13 s_A(x1) = x1 + 12 mark#_A(x1) = max{52, x1 + 51} zprimes_A = 59 a__zprimes#_A = 109 a__nats#_A(x1) = max{56, x1 + 53} |0|_A = 12 nats_A(x1) = x1 + 9 mark_A(x1) = max{7, x1} sieve_A(x1) = max{28, x1 + 21} a__sieve#_A(x1) = max{71, x1 + 64} filter_A(x1,x2,x3) = max{x1 + 46, x2 + 50, x3 + 48} a__nats_A(x1) = max{10, x1 + 8} a__filter_A(x1,x2,x3) = max{x1 + 47, x2 + 51, x3 + 49} a__sieve_A(x1) = max{29, x1 + 22} a__zprimes_A = 8 precedence: a__filter# = cons = s = mark# = zprimes = a__zprimes# = a__nats# = |0| = nats = mark = sieve = a__sieve# = filter = a__nats = a__filter = a__sieve = a__zprimes partial status: pi(a__filter#) = [] pi(cons) = [1] pi(s) = [1] pi(mark#) = [1] pi(zprimes) = [] pi(a__zprimes#) = [] pi(a__nats#) = [] pi(|0|) = [] pi(nats) = [1] pi(mark) = [1] pi(sieve) = [1] pi(a__sieve#) = [1] pi(filter) = [3] pi(a__nats) = [1] pi(a__filter) = [] pi(a__sieve) = [] pi(a__zprimes) = [] The next rules are strictly ordered: p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16 We remove them from the problem. Then no dependency pair remains.