YES Problem: c(b(a(a(x1)))) -> a(a(b(c(x1)))) b(a(a(a(x1)))) -> a(a(a(b(x1)))) a(b(c(x1))) -> c(b(a(x1))) c(c(b(b(x1)))) -> b(b(c(c(x1)))) Proof: Matrix Interpretation Processor: dim=2 interpretation: [1 0] [0] [c](x0) = [0 2]x0 + [1], [2 0] [b](x0) = [0 1]x0, [1 1] [1] [a](x0) = [0 1]x0 + [0] orientation: [2 4] [4] [2 4] [4] c(b(a(a(x1)))) = [0 2]x1 + [1] >= [0 2]x1 + [1] = a(a(b(c(x1)))) [2 6] [6] [2 3] [3] b(a(a(a(x1)))) = [0 1]x1 + [0] >= [0 1]x1 + [0] = a(a(a(b(x1)))) [2 2] [2] [2 2] [2] a(b(c(x1))) = [0 2]x1 + [1] >= [0 2]x1 + [1] = c(b(a(x1))) [4 0] [0] [4 0] [0] c(c(b(b(x1)))) = [0 4]x1 + [3] >= [0 4]x1 + [3] = b(b(c(c(x1)))) problem: c(b(a(a(x1)))) -> a(a(b(c(x1)))) a(b(c(x1))) -> c(b(a(x1))) c(c(b(b(x1)))) -> b(b(c(c(x1)))) String Reversal Processor: a(a(b(c(x1)))) -> c(b(a(a(x1)))) c(b(a(x1))) -> a(b(c(x1))) b(b(c(c(x1)))) -> c(c(b(b(x1)))) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [c](x0) = [0 0 1]x0 [0 1 0] , [1 0 1] [0] [b](x0) = [0 0 0]x0 + [0] [0 1 1] [1], [1 1 0] [a](x0) = [0 1 1]x0 [0 0 0] orientation: [1 2 1] [1] [1 2 1] [0] a(a(b(c(x1)))) = [0 1 1]x1 + [1] >= [0 1 1]x1 + [1] = c(b(a(a(x1)))) [0 0 0] [0] [0 0 0] [0] [1 1 0] [0] [1 1 0] [0] c(b(a(x1))) = [0 1 1]x1 + [1] >= [0 1 1]x1 + [1] = a(b(c(x1))) [0 0 0] [0] [0 0 0] [0] [1 1 2] [1] [1 1 2] [1] b(b(c(c(x1)))) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = c(c(b(b(x1)))) [0 1 1] [2] [0 1 1] [2] problem: c(b(a(x1))) -> a(b(c(x1))) b(b(c(c(x1)))) -> c(c(b(b(x1)))) KBO Processor: weight function: w0 = 1 w(c) = w(b) = w(a) = 1 precedence: b > c > a problem: Qed