YES Problem: f(s(x1)) -> s(s(f(p(s(x1))))) f(0(x1)) -> 0(x1) p(s(x1)) -> x1 Proof: DP Processor: DPs: f#(s(x1)) -> p#(s(x1)) f#(s(x1)) -> f#(p(s(x1))) TRS: f(s(x1)) -> s(s(f(p(s(x1))))) f(0(x1)) -> 0(x1) p(s(x1)) -> x1 Usable Rule Processor: DPs: f#(s(x1)) -> p#(s(x1)) f#(s(x1)) -> f#(p(s(x1))) TRS: p(s(x1)) -> x1 Arctic Interpretation Processor: dimension: 2 usable rules: p(s(x1)) -> x1 interpretation: [p#](x0) = [-& 0 ]x0 + [0], [f#](x0) = [-& 1 ]x0 + [3], [-& 2 ] [1] [p](x0) = [0 -4]x0 + [1], [-& 2 ] [0] [s](x0) = [-1 3 ]x0 + [3] orientation: f#(s(x1)) = [0 4]x1 + [4] >= [-1 3 ]x1 + [3] = p#(s(x1)) f#(s(x1)) = [0 4]x1 + [4] >= [-4 3 ]x1 + [3] = f#(p(s(x1))) [1 5 ] [5] p(s(x1)) = [-5 2 ]x1 + [1] >= x1 = x1 problem: DPs: TRS: p(s(x1)) -> x1 Qed