YES Problem: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) Proof: DP Processor: DPs: a#(b(b(x1))) -> a#(x1) a#(b(b(x1))) -> a#(a(x1)) TRS: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) Arctic Interpretation Processor: dimension: 2 usable rules: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) interpretation: [-& 0 ] [1] [b](x0) = [1 -&]x0 + [1], [0 -&] [-&] [a](x0) = [2 0 ]x0 + [2 ], [a#](x0) = [1 0]x0 orientation: a#(b(b(x1))) = [2 1]x1 + [2] >= [1 0]x1 = a#(x1) a#(b(b(x1))) = [2 1]x1 + [2] >= [2 0]x1 + [2] = a#(a(x1)) [2 0] [2] [2 -&] [2] a(b(a(x1))) = [4 2]x1 + [4] >= [-& 2 ]x1 + [3] = b(b(b(b(x1)))) [1 -&] [1] [1 -&] [1] a(b(b(x1))) = [3 1 ]x1 + [3] >= [3 1 ]x1 + [3] = b(b(a(a(x1)))) problem: DPs: a#(b(b(x1))) -> a#(a(x1)) TRS: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) Restore Modifier: DPs: a#(b(b(x1))) -> a#(a(x1)) TRS: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) Arctic Interpretation Processor: dimension: 2 usable rules: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) interpretation: [-& 1 ] [0 ] [b](x0) = [0 -&]x0 + [-4], [-1 3 ] [2 ] [a](x0) = [-& 0 ]x0 + [-2], [a#](x0) = [-3 3 ]x0 + [2] orientation: a#(b(b(x1))) = [-2 4 ]x1 + [3] >= [-4 3 ]x1 + [2] = a#(a(x1)) [2 6 ] [5] [2 -&] [1] a(b(a(x1))) = [-1 3 ]x1 + [2] >= [-& 2 ]x1 + [1] = b(b(b(b(x1)))) [0 4 ] [3] [-1 4 ] [3] a(b(b(x1))) = [-& 1 ]x1 + [0] >= [-& 1 ]x1 + [0] = b(b(a(a(x1)))) problem: DPs: TRS: a(b(a(x1))) -> b(b(b(b(x1)))) a(b(b(x1))) -> b(b(a(a(x1)))) Qed