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: Arctic Interpretation Processor: dimension: 2 interpretation: [0 -&] [c](x0) = [0 -&]x0, [0 0] [a](x0) = [1 1]x0, [0 -&] [b](x0) = [0 0 ]x0 orientation: [1 1] [0 0] a(a(b(x1))) = [2 2]x1 >= [1 1]x1 = b(a(b(c(a(x1))))) [0 0] [0 0] b(a(x1)) = [1 1]x1 >= [1 1]x1 = a(b(b(x1))) [0 0] [0 0] b(c(a(x1))) = [0 0]x1 >= [0 0]x1 = c(a(b(x1))) problem: b(a(x1)) -> a(b(b(x1))) b(c(a(x1))) -> c(a(b(x1))) KBO Processor: weight function: w0 = 1 w(c) = w(a) = 1 w(b) = 0 precedence: b > c ~ a problem: Qed