YES Problem: a(a(b(b(x1)))) -> b(b(b(a(a(a(x1)))))) Proof: DP Processor: DPs: a#(a(b(b(x1)))) -> a#(x1) a#(a(b(b(x1)))) -> a#(a(x1)) a#(a(b(b(x1)))) -> a#(a(a(x1))) TRS: a(a(b(b(x1)))) -> b(b(b(a(a(a(x1)))))) Matrix Interpretation Processor: dim=5 interpretation: [a#](x0) = [1 0 0 0 0]x0, [0 0 0 1 1] [1 0 1 0 0] [a](x0) = [0 0 0 0 1]x0 [0 0 0 0 0] [1 0 0 0 0] , [0 0 0 0 0] [0] [1 0 0 1 1] [1] [b](x0) = [1 0 0 0 0]x0 + [0] [0 0 1 0 0] [0] [0 1 0 0 0] [0] orientation: a#(a(b(b(x1)))) = [2 0 0 1 1]x1 + [1] >= [1 0 0 0 0]x1 = a#(x1) a#(a(b(b(x1)))) = [2 0 0 1 1]x1 + [1] >= [0 0 0 1 1]x1 = a#(a(x1)) a#(a(b(b(x1)))) = [2 0 0 1 1]x1 + [1] >= [1 0 0 0 0]x1 = a#(a(a(x1))) [0 0 0 0 0] [0] [0 0 0 0 0] [0] [3 0 0 2 2] [2] [1 0 0 2 2] [2] a(a(b(b(x1)))) = [0 0 0 0 0]x1 + [0] >= [0 0 0 0 0]x1 + [0] = b(b(b(a(a(a(x1)))))) [0 0 0 0 0] [0] [0 0 0 0 0] [0] [2 0 0 1 1] [1] [2 0 0 1 1] [1] problem: DPs: TRS: a(a(b(b(x1)))) -> b(b(b(a(a(a(x1)))))) Qed