YES Problem: a(b(a(x))) -> b(a(b(x))) Proof: Arctic Interpretation Processor: dimension: 2 interpretation: [0 1] [b](x0) = [1 0]x0, [0 3] [a](x0) = [3 2]x0 orientation: [6 7] [4 5] a(b(a(x))) = [7 6]x >= [5 4]x = b(a(b(x))) problem: Qed