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. lexicographic path order with precedence: precedence: rand > s > conv > nil > cons > lastbit > |0| > half > conv# argument filter: pi(conv#) = [1] pi(s) = 1 pi(half) = 1 pi(|0|) = [] pi(lastbit) = [] pi(conv) = [] pi(cons) = 1 pi(nil) = [] pi(rand) = [1] 2. lexicographic path order with precedence: precedence: nil > lastbit > half > conv > s > rand > cons > |0| > conv# argument filter: pi(conv#) = 1 pi(s) = [1] pi(half) = 1 pi(|0|) = [] pi(lastbit) = [] pi(conv) = [] pi(cons) = 1 pi(nil) = [] pi(rand) = [] 3. lexicographic path order with precedence: precedence: nil > cons > lastbit > s > rand > conv# > half > |0| > conv argument filter: pi(conv#) = 1 pi(s) = [] pi(half) = [] pi(|0|) = [] pi(lastbit) = [] pi(conv) = [] pi(cons) = 1 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. lexicographic path order with precedence: precedence: rand > half > s > cons > |0| > nil > lastbit > conv > half# argument filter: pi(half#) = 1 pi(s) = 1 pi(half) = 1 pi(|0|) = [] pi(lastbit) = 1 pi(conv) = [1] pi(cons) = 2 pi(nil) = [] pi(rand) = [1] 2. lexicographic path order with precedence: precedence: s > rand > nil > cons > |0| > lastbit > half > conv > half# argument filter: pi(half#) = [1] pi(s) = 1 pi(half) = [1] pi(|0|) = [] pi(lastbit) = 1 pi(conv) = [1] pi(cons) = 2 pi(nil) = [] pi(rand) = 1 3. lexicographic path order with precedence: precedence: nil > lastbit > half > s > rand > cons > |0| > conv > half# argument filter: pi(half#) = 1 pi(s) = [1] 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. lexicographic path order with precedence: precedence: rand > half > s > cons > |0| > nil > lastbit > conv > lastbit# argument filter: pi(lastbit#) = 1 pi(s) = 1 pi(half) = 1 pi(|0|) = [] pi(lastbit) = 1 pi(conv) = [1] pi(cons) = 2 pi(nil) = [] pi(rand) = [1] 2. lexicographic path order with precedence: precedence: s > rand > nil > cons > |0| > lastbit > half > conv > lastbit# argument filter: pi(lastbit#) = [1] pi(s) = 1 pi(half) = [1] pi(|0|) = [] pi(lastbit) = 1 pi(conv) = [1] pi(cons) = 2 pi(nil) = [] pi(rand) = 1 3. lexicographic path order with precedence: precedence: nil > lastbit > half > s > rand > cons > |0| > conv > lastbit# argument filter: pi(lastbit#) = 1 pi(s) = [1] 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.