YES Problem: 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) zero(0()) -> true() zero(s(x)) -> false() conv(x) -> conviter(x,cons(0(),nil())) conviter(x,l) -> if(zero(x),x,l) if(true(),x,l) -> l if(false(),x,l) -> conviter(half(x),cons(lastbit(x),l)) Proof: DP Processor: DPs: half#(s(s(x))) -> half#(x) lastbit#(s(s(x))) -> lastbit#(x) conv#(x) -> conviter#(x,cons(0(),nil())) conviter#(x,l) -> zero#(x) conviter#(x,l) -> if#(zero(x),x,l) if#(false(),x,l) -> lastbit#(x) if#(false(),x,l) -> half#(x) if#(false(),x,l) -> conviter#(half(x),cons(lastbit(x),l)) TRS: 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) zero(0()) -> true() zero(s(x)) -> false() conv(x) -> conviter(x,cons(0(),nil())) conviter(x,l) -> if(zero(x),x,l) if(true(),x,l) -> l if(false(),x,l) -> conviter(half(x),cons(lastbit(x),l)) Usable Rule Processor: DPs: half#(s(s(x))) -> half#(x) lastbit#(s(s(x))) -> lastbit#(x) conv#(x) -> conviter#(x,cons(0(),nil())) conviter#(x,l) -> zero#(x) conviter#(x,l) -> if#(zero(x),x,l) if#(false(),x,l) -> lastbit#(x) if#(false(),x,l) -> half#(x) if#(false(),x,l) -> conviter#(half(x),cons(lastbit(x),l)) TRS: zero(0()) -> true() zero(s(x)) -> false() lastbit(0()) -> 0() lastbit(s(0())) -> s(0()) lastbit(s(s(x))) -> lastbit(x) half(0()) -> 0() half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) Arctic Interpretation Processor: dimension: 1 usable rules: zero(0()) -> true() zero(s(x)) -> false() half(0()) -> 0() half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) interpretation: [if#](x0, x1, x2) = -4x0 + -1x1 + 0, [conviter#](x0, x1) = x0 + 1, [conv#](x0) = 2x0 + 12, [zero#](x0) = 0, [lastbit#](x0) = -2x0 + 0, [half#](x0) = -4x0 + 0, [cons](x0, x1) = x0 + x1 + -16, [nil] = 2, [false] = 6, [true] = 1, [zero](x0) = 3x0 + 4, [lastbit](x0) = -4x0 + 0, [s](x0) = 3x0 + 4, [half](x0) = -2x0 + 1, [0] = 0 orientation: half#(s(s(x))) = 2x + 3 >= -4x + 0 = half#(x) lastbit#(s(s(x))) = 4x + 5 >= -2x + 0 = lastbit#(x) conv#(x) = 2x + 12 >= x + 1 = conviter#(x,cons(0(),nil())) conviter#(x,l) = x + 1 >= 0 = zero#(x) conviter#(x,l) = x + 1 >= -1x + 0 = if#(zero(x),x,l) if#(false(),x,l) = -1x + 2 >= -2x + 0 = lastbit#(x) if#(false(),x,l) = -1x + 2 >= -4x + 0 = half#(x) if#(false(),x,l) = -1x + 2 >= -2x + 1 = conviter#(half(x),cons(lastbit(x),l)) zero(0()) = 4 >= 1 = true() zero(s(x)) = 6x + 7 >= 6 = false() lastbit(0()) = 0 >= 0 = 0() lastbit(s(0())) = 0 >= 4 = s(0()) lastbit(s(s(x))) = 2x + 3 >= -4x + 0 = lastbit(x) half(0()) = 1 >= 0 = 0() half(s(0())) = 2 >= 0 = 0() half(s(s(x))) = 4x + 5 >= 1x + 4 = s(half(x)) problem: DPs: TRS: zero(0()) -> true() zero(s(x)) -> false() lastbit(0()) -> 0() lastbit(s(0())) -> s(0()) lastbit(s(s(x))) -> lastbit(x) half(0()) -> 0() half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) Qed