YES Problem: a(b(c(x1))) -> a(a(b(x1))) a(b(c(x1))) -> b(c(b(c(x1)))) a(b(c(x1))) -> c(b(c(a(x1)))) Proof: DP Processor: DPs: a#(b(c(x1))) -> a#(b(x1)) a#(b(c(x1))) -> a#(a(b(x1))) a#(b(c(x1))) -> a#(x1) TRS: a(b(c(x1))) -> a(a(b(x1))) a(b(c(x1))) -> b(c(b(c(x1)))) a(b(c(x1))) -> c(b(c(a(x1)))) Matrix Interpretation Processor: dim=4 interpretation: [a#](x0) = [1 1 0 0]x0, [1 1 0 0] [0] [0 0 0 0] [1] [a](x0) = [0 0 0 0]x0 + [0] [1 1 0 0] [0], [1 0 0 1] [0 1 0 0] [b](x0) = [0 0 0 0]x0 [0 0 0 0] , [0 1 0 0] [0] [0 0 0 1] [1] [c](x0) = [0 0 0 0]x0 + [0] [1 0 1 0] [0] orientation: a#(b(c(x1))) = [1 1 1 1]x1 + [1] >= [1 1 0 1]x1 = a#(b(x1)) a#(b(c(x1))) = [1 1 1 1]x1 + [1] >= [1 1 0 1]x1 + [1] = a#(a(b(x1))) a#(b(c(x1))) = [1 1 1 1]x1 + [1] >= [1 1 0 0]x1 = a#(x1) [1 1 1 1] [1] [1 1 0 1] [1] [0 0 0 0] [1] [0 0 0 0] [1] a(b(c(x1))) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = a(a(b(x1))) [1 1 1 1] [1] [1 1 0 1] [1] [1 1 1 1] [1] [1 1 1 1] [1] [0 0 0 0] [1] [0 0 0 0] [1] a(b(c(x1))) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = b(c(b(c(x1)))) [1 1 1 1] [1] [0 0 0 0] [0] [1 1 1 1] [1] [1 1 0 0] [1] [0 0 0 0] [1] [0 0 0 0] [1] a(b(c(x1))) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = c(b(c(a(x1)))) [1 1 1 1] [1] [1 1 0 0] [1] problem: DPs: a#(b(c(x1))) -> a#(a(b(x1))) TRS: a(b(c(x1))) -> a(a(b(x1))) a(b(c(x1))) -> b(c(b(c(x1)))) a(b(c(x1))) -> c(b(c(a(x1)))) Arctic Interpretation Processor: dimension: 2 interpretation: [a#](x0) = [0 0]x0 + [0], [-& 1 ] [0] [a](x0) = [-& 0 ]x0 + [2], [-& 0 ] [0] [b](x0) = [0 -&]x0 + [1], [2 -&] [3] [c](x0) = [-& -&]x0 + [0] orientation: a#(b(c(x1))) = [2 -&]x1 + [3] >= [1 -&]x1 + [2] = a#(a(b(x1))) [3 -&] [4] [1 -&] [3] a(b(c(x1))) = [2 -&]x1 + [3] >= [0 -&]x1 + [2] = a(a(b(x1))) [3 -&] [4] [0] a(b(c(x1))) = [2 -&]x1 + [3] >= [3] = b(c(b(c(x1)))) [3 -&] [4] [3] a(b(c(x1))) = [2 -&]x1 + [3] >= [0] = c(b(c(a(x1)))) problem: DPs: TRS: a(b(c(x1))) -> a(a(b(x1))) a(b(c(x1))) -> b(c(b(c(x1)))) a(b(c(x1))) -> c(b(c(a(x1)))) Qed