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