YES Problem: f(g(x,y),f(y,y)) -> f(g(y,x),y) Proof: Matrix Interpretation Processor: dim=1 interpretation: [f](x0, x1) = x0 + x1 + 5, [g](x0, x1) = 4x0 + 4x1 + 5 orientation: f(g(x,y),f(y,y)) = 4x + 6y + 15 >= 4x + 5y + 10 = f(g(y,x),y) problem: Qed