YES We show the termination of the TRS R: half(|0|()) -> |0|() half(s(|0|())) -> |0|() half(s(s(x))) -> s(half(x)) inc(|0|()) -> |0|() inc(s(x)) -> s(inc(x)) zero(|0|()) -> true() zero(s(x)) -> false() p(|0|()) -> |0|() p(s(x)) -> x bits(x) -> bitIter(x,|0|()) bitIter(x,y) -> if(zero(x),x,inc(y)) if(true(),x,y) -> p(y) if(false(),x,y) -> bitIter(half(x),y) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: half#(s(s(x))) -> half#(x) p2: inc#(s(x)) -> inc#(x) p3: bits#(x) -> bitIter#(x,|0|()) p4: bitIter#(x,y) -> if#(zero(x),x,inc(y)) p5: bitIter#(x,y) -> zero#(x) p6: bitIter#(x,y) -> inc#(y) p7: if#(true(),x,y) -> p#(y) p8: if#(false(),x,y) -> bitIter#(half(x),y) p9: if#(false(),x,y) -> half#(x) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: inc(|0|()) -> |0|() r5: inc(s(x)) -> s(inc(x)) r6: zero(|0|()) -> true() r7: zero(s(x)) -> false() r8: p(|0|()) -> |0|() r9: p(s(x)) -> x r10: bits(x) -> bitIter(x,|0|()) r11: bitIter(x,y) -> if(zero(x),x,inc(y)) r12: if(true(),x,y) -> p(y) r13: if(false(),x,y) -> bitIter(half(x),y) The estimated dependency graph contains the following SCCs: {p4, p8} {p1} {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: bitIter#(x,y) -> if#(zero(x),x,inc(y)) p2: if#(false(),x,y) -> bitIter#(half(x),y) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: inc(|0|()) -> |0|() r5: inc(s(x)) -> s(inc(x)) r6: zero(|0|()) -> true() r7: zero(s(x)) -> false() r8: p(|0|()) -> |0|() r9: p(s(x)) -> x r10: bits(x) -> bitIter(x,|0|()) r11: bitIter(x,y) -> if(zero(x),x,inc(y)) r12: if(true(),x,y) -> p(y) r13: if(false(),x,y) -> bitIter(half(x),y) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: bitIter#_A(x1,x2) = x1 + 7 if#_A(x1,x2,x3) = max{x1, x2 + 3} zero_A(x1) = max{6, x1 - 3} inc_A(x1) = max{15, x1 + 10} false_A = 10 half_A(x1) = max{2, x1 - 8} |0|_A = 2 s_A(x1) = max{14, x1 + 9} true_A = 5 p_A(x1) = max{4, x1 - 17} base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: bitIter#_A(x1,x2) = 0 if#_A(x1,x2,x3) = 0 zero_A(x1) = x1 + 1 inc_A(x1) = x1 + 1 false_A() = 3 half_A(x1) = 3 |0|_A() = 0 s_A(x1) = 2 true_A() = 1 p_A(x1) = 1 bitIter#!_A(x1,x2) = 1 if#!_A(x1,x2,x3) = x2 zero!_A(x1) = 5 inc!_A(x1) = 6 false!_A() = 2 half!_A(x1) = x1 + 4 |0|!_A() = 0 s!_A(x1) = 5 true!_A() = 1 p!_A(x1) = 2 partial status: pi(bitIter#) = [] pi(if#) = [1] pi(zero) = [] pi(inc) = [1] pi(false) = [] pi(half) = [] pi(|0|) = [] pi(s) = [] pi(true) = [] pi(p) = [] 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: 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: inc(|0|()) -> |0|() r5: inc(s(x)) -> s(inc(x)) r6: zero(|0|()) -> true() r7: zero(s(x)) -> false() r8: p(|0|()) -> |0|() r9: p(s(x)) -> x r10: bits(x) -> bitIter(x,|0|()) r11: bitIter(x,y) -> if(zero(x),x,inc(y)) r12: if(true(),x,y) -> p(y) r13: if(false(),x,y) -> bitIter(half(x),y) 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: half#_A(x1) = max{26, x1 + 13} s_A(x1) = x1 + 13 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: half#_A(x1) = x1 s_A(x1) = x1 + 3 half#!_A(x1) = x1 + 1 s!_A(x1) = x1 + 1 partial status: pi(half#) = [] 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: inc#(s(x)) -> inc#(x) and R consists of: r1: half(|0|()) -> |0|() r2: half(s(|0|())) -> |0|() r3: half(s(s(x))) -> s(half(x)) r4: inc(|0|()) -> |0|() r5: inc(s(x)) -> s(inc(x)) r6: zero(|0|()) -> true() r7: zero(s(x)) -> false() r8: p(|0|()) -> |0|() r9: p(s(x)) -> x r10: bits(x) -> bitIter(x,|0|()) r11: bitIter(x,y) -> if(zero(x),x,inc(y)) r12: if(true(),x,y) -> p(y) r13: if(false(),x,y) -> bitIter(half(x),y) The set of usable rules consists of r1, r2 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: inc#_A(x1) = max{20, x1 + 14} s_A(x1) = max{19, x1 + 7} half_A(x1) = max{15, x1 + 2} |0|_A = 8 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: inc#_A(x1) = x1 s_A(x1) = x1 + 10 half_A(x1) = x1 + 1 |0|_A() = 2 inc#!_A(x1) = 20 s!_A(x1) = 19 half!_A(x1) = x1 |0|!_A() = 13 partial status: pi(inc#) = [] pi(s) = [1] pi(half) = [1] pi(|0|) = [] The following rules are removed: p1 Then no dependency pair remains.