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