YES We show the termination of the relative TRS R/S: R: half(|0|()) -> |0|() half(s(|0|())) -> |0|() half(s(s(x))) -> s(half(x)) lastbit(|0|()) -> |0|() lastbit(s(|0|())) -> s(|0|()) lastbit(s(s(x))) -> lastbit(x) conv(|0|()) -> cons(nil(),|0|()) conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x))) S: rand(x) -> x rand(x) -> rand(s(x)) -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: half#(s(s(x))) -> half#(x) p2: lastbit#(s(s(x))) -> lastbit#(x) p3: conv#(s(x)) -> conv#(half(s(x))) p4: conv#(s(x)) -> half#(s(x)) p5: conv#(s(x)) -> lastbit#(s(x)) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: lastbit(|0|()) -> |0|() r5: lastbit(s(|0|())) -> s(|0|()) r6: lastbit(s(s(x))) -> lastbit(x) r7: conv(|0|()) -> cons(nil(),|0|()) r8: conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x))) r9: rand(x) -> x r10: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p3} {p1} {p2} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: conv#(s(x)) -> conv#(half(s(x))) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: lastbit(|0|()) -> |0|() r5: lastbit(s(|0|())) -> s(|0|()) r6: lastbit(s(s(x))) -> lastbit(x) r7: conv(|0|()) -> cons(nil(),|0|()) r8: conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x))) r9: rand(x) -> x r10: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: conv#_A(x1) = x1 + 2 s_A(x1) = x1 half_A(x1) = x1 |0|_A = 7 lastbit_A(x1) = max{5, x1 + 3} conv_A(x1) = x1 + 4 cons_A(x1,x2) = max{3, x1 - 1, x2 - 4} nil_A = 8 rand_A(x1) = x1 + 2 precedence: conv# = s = half = |0| = lastbit = conv = cons = nil = rand partial status: pi(conv#) = [] pi(s) = [] pi(half) = [] pi(|0|) = [] pi(lastbit) = [] pi(conv) = [] pi(cons) = [] pi(nil) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: conv#_A(x1) = max{0, x1 - 11} s_A(x1) = max{16, x1 + 12} half_A(x1) = max{6, x1 - 5} |0|_A = 5 lastbit_A(x1) = 43 conv_A(x1) = x1 + 26 cons_A(x1,x2) = 43 nil_A = 8 rand_A(x1) = 0 precedence: cons > lastbit = conv = nil > s = half = |0| > conv# = rand partial status: pi(conv#) = [] pi(s) = [1] pi(half) = [] pi(|0|) = [] pi(lastbit) = [] pi(conv) = [1] pi(cons) = [] pi(nil) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: half#(s(s(x))) -> half#(x) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: lastbit(|0|()) -> |0|() r5: lastbit(s(|0|())) -> s(|0|()) r6: lastbit(s(s(x))) -> lastbit(x) r7: conv(|0|()) -> cons(nil(),|0|()) r8: conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x))) r9: rand(x) -> x r10: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: half#_A(x1) = max{10, x1} s_A(x1) = max{11, x1} half_A(x1) = max{11, x1} |0|_A = 7 lastbit_A(x1) = max{12, x1 + 3} conv_A(x1) = max{15, x1 + 13} cons_A(x1,x2) = max{6, x1 - 25} nil_A = 6 rand_A(x1) = max{22, x1 + 11} precedence: half# = s > conv > half = |0| = lastbit = cons = nil = rand partial status: pi(half#) = [1] pi(s) = [1] pi(half) = [1] pi(|0|) = [] pi(lastbit) = [1] pi(conv) = [1] pi(cons) = [] pi(nil) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: half#_A(x1) = 25 s_A(x1) = 10 half_A(x1) = max{18, x1 + 13} |0|_A = 24 lastbit_A(x1) = 9 conv_A(x1) = max{18, x1 + 2} cons_A(x1,x2) = 11 nil_A = 23 rand_A(x1) = 1 precedence: half# = s = half = |0| = lastbit = conv = cons = nil = rand partial status: pi(half#) = [] pi(s) = [] pi(half) = [1] pi(|0|) = [] pi(lastbit) = [] pi(conv) = [1] pi(cons) = [] pi(nil) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: lastbit#(s(s(x))) -> lastbit#(x) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: lastbit(|0|()) -> |0|() r5: lastbit(s(|0|())) -> s(|0|()) r6: lastbit(s(s(x))) -> lastbit(x) r7: conv(|0|()) -> cons(nil(),|0|()) r8: conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x))) r9: rand(x) -> x r10: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: lastbit#_A(x1) = max{10, x1} s_A(x1) = max{11, x1} half_A(x1) = max{11, x1} |0|_A = 7 lastbit_A(x1) = max{12, x1 + 3} conv_A(x1) = max{15, x1 + 13} cons_A(x1,x2) = max{6, x1 - 25} nil_A = 6 rand_A(x1) = max{22, x1 + 11} precedence: lastbit# = s > conv > half = |0| = lastbit = cons = nil = rand partial status: pi(lastbit#) = [1] pi(s) = [1] pi(half) = [1] pi(|0|) = [] pi(lastbit) = [1] pi(conv) = [1] pi(cons) = [] pi(nil) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: lastbit#_A(x1) = 25 s_A(x1) = 10 half_A(x1) = max{18, x1 + 13} |0|_A = 24 lastbit_A(x1) = 9 conv_A(x1) = max{18, x1 + 2} cons_A(x1,x2) = 11 nil_A = 23 rand_A(x1) = 1 precedence: lastbit# = s = half = |0| = lastbit = conv = cons = nil = rand partial status: pi(lastbit#) = [] pi(s) = [] pi(half) = [1] pi(|0|) = [] pi(lastbit) = [] pi(conv) = [1] pi(cons) = [] pi(nil) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.