YES Problem: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(half(x)))) Proof: DP Processor: DPs: half#(s(s(x))) -> half#(x) log#(s(s(x))) -> half#(x) log#(s(s(x))) -> log#(s(half(x))) TRS: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(half(x)))) Usable Rule Processor: DPs: half#(s(s(x))) -> half#(x) log#(s(s(x))) -> half#(x) log#(s(s(x))) -> log#(s(half(x))) TRS: half(0()) -> 0() half(s(s(x))) -> s(half(x)) Arctic Interpretation Processor: dimension: 1 usable rules: half(0()) -> 0() half(s(s(x))) -> s(half(x)) interpretation: [log#](x0) = x0 + 0, [half#](x0) = x0 + 0, [s](x0) = 1x0 + 4, [half](x0) = x0 + 2, [0] = 0 orientation: half#(s(s(x))) = 2x + 5 >= x + 0 = half#(x) log#(s(s(x))) = 2x + 5 >= x + 0 = half#(x) log#(s(s(x))) = 2x + 5 >= 1x + 4 = log#(s(half(x))) half(0()) = 2 >= 0 = 0() half(s(s(x))) = 2x + 5 >= 1x + 4 = s(half(x)) problem: DPs: TRS: half(0()) -> 0() half(s(s(x))) -> s(half(x)) Qed