YES Problem: a(a(b(x1))) -> b(a(b(c(a(x1))))) b(a(x1)) -> a(b(b(x1))) b(c(a(x1))) -> c(a(b(x1))) Proof: DP Processor: DPs: a#(a(b(x1))) -> a#(x1) a#(a(b(x1))) -> b#(c(a(x1))) a#(a(b(x1))) -> a#(b(c(a(x1)))) a#(a(b(x1))) -> b#(a(b(c(a(x1))))) b#(a(x1)) -> b#(x1) b#(a(x1)) -> b#(b(x1)) b#(a(x1)) -> a#(b(b(x1))) b#(c(a(x1))) -> b#(x1) b#(c(a(x1))) -> a#(b(x1)) TRS: a(a(b(x1))) -> b(a(b(c(a(x1))))) b(a(x1)) -> a(b(b(x1))) b(c(a(x1))) -> c(a(b(x1))) Matrix Interpretation Processor: dim=2 interpretation: [b#](x0) = [1 0]x0 + [2], [a#](x0) = [0 2]x0 + [1], [1 0] [c](x0) = [0 0]x0, [1 2] [1] [a](x0) = [2 1]x0 + [2], [b](x0) = x0 orientation: a#(a(b(x1))) = [4 2]x1 + [5] >= [0 2]x1 + [1] = a#(x1) a#(a(b(x1))) = [4 2]x1 + [5] >= [1 2]x1 + [3] = b#(c(a(x1))) a#(a(b(x1))) = [4 2]x1 + [5] >= [1] = a#(b(c(a(x1)))) a#(a(b(x1))) = [4 2]x1 + [5] >= [1 2]x1 + [4] = b#(a(b(c(a(x1))))) b#(a(x1)) = [1 2]x1 + [3] >= [1 0]x1 + [2] = b#(x1) b#(a(x1)) = [1 2]x1 + [3] >= [1 0]x1 + [2] = b#(b(x1)) b#(a(x1)) = [1 2]x1 + [3] >= [0 2]x1 + [1] = a#(b(b(x1))) b#(c(a(x1))) = [1 2]x1 + [3] >= [1 0]x1 + [2] = b#(x1) b#(c(a(x1))) = [1 2]x1 + [3] >= [0 2]x1 + [1] = a#(b(x1)) [5 4] [6] [1 2] [2] a(a(b(x1))) = [4 5]x1 + [6] >= [2 4]x1 + [4] = b(a(b(c(a(x1))))) [1 2] [1] [1 2] [1] b(a(x1)) = [2 1]x1 + [2] >= [2 1]x1 + [2] = a(b(b(x1))) [1 2] [1] [1 2] [1] b(c(a(x1))) = [0 0]x1 + [0] >= [0 0]x1 + [0] = c(a(b(x1))) problem: DPs: TRS: a(a(b(x1))) -> b(a(b(c(a(x1))))) b(a(x1)) -> a(b(b(x1))) b(c(a(x1))) -> c(a(b(x1))) Qed