YES Problem: f(0(x1)) -> s(0(x1)) d(0(x1)) -> 0(x1) d(s(x1)) -> s(s(d(x1))) f(s(x1)) -> d(f(x1)) Proof: Arctic Interpretation Processor: dimension: 2 interpretation: [0 0 ] [d](x0) = [-& 0 ]x0, [0 0 ] [s](x0) = [-& 0 ]x0, [2 0] [f](x0) = [0 0]x0, [0 2 ] [0](x0) = [-& -&]x0 orientation: [2 4] [0 2 ] f(0(x1)) = [0 2]x1 >= [-& -&]x1 = s(0(x1)) [0 2 ] [0 2 ] d(0(x1)) = [-& -&]x1 >= [-& -&]x1 = 0(x1) [0 0 ] [0 0 ] d(s(x1)) = [-& 0 ]x1 >= [-& 0 ]x1 = s(s(d(x1))) [2 2] [2 0] f(s(x1)) = [0 0]x1 >= [0 0]x1 = d(f(x1)) problem: d(0(x1)) -> 0(x1) d(s(x1)) -> s(s(d(x1))) f(s(x1)) -> d(f(x1)) Arctic Interpretation Processor: dimension: 2 interpretation: [0 0 ] [d](x0) = [-& 1 ]x0, [0 -&] [s](x0) = [0 0 ]x0, [1 0 ] [f](x0) = [-& -&]x0, [0 -&] [0](x0) = [3 0 ]x0 orientation: [3 0] [0 -&] d(0(x1)) = [4 1]x1 >= [3 0 ]x1 = 0(x1) [0 0] [0 0] d(s(x1)) = [1 1]x1 >= [0 1]x1 = s(s(d(x1))) [1 0 ] [1 0 ] f(s(x1)) = [-& -&]x1 >= [-& -&]x1 = d(f(x1)) problem: d(s(x1)) -> s(s(d(x1))) f(s(x1)) -> d(f(x1)) String Reversal Processor: s(d(x1)) -> d(s(s(x1))) s(f(x1)) -> f(d(x1)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [d](x0) = [0 1 1]x0 [0 1 1] , [1 1 1] [s](x0) = [0 1 0]x0 [0 0 1] , [1 0 0] [0] [f](x0) = [0 0 0]x0 + [1] [0 0 0] [0] orientation: [1 2 2] [1 2 2] s(d(x1)) = [0 1 1]x1 >= [0 1 1]x1 = d(s(s(x1))) [0 1 1] [0 1 1] [1 0 0] [1] [1 0 0] [0] s(f(x1)) = [0 0 0]x1 + [1] >= [0 0 0]x1 + [1] = f(d(x1)) [0 0 0] [0] [0 0 0] [0] problem: s(d(x1)) -> d(s(s(x1))) KBO Processor: weight function: w0 = 1 w(d) = 1 w(s) = 0 precedence: s > d problem: Qed