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