YES Problem: minus(minus(x)) -> x minus(h(x)) -> h(minus(x)) minus(f(x,y)) -> f(minus(y),minus(x)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [f](x0, x1) = 2x0 + 2x1 + 1, [h](x0) = 4x0 + 2, [minus](x0) = 4x0 + 1 orientation: minus(minus(x)) = 16x + 5 >= x = x minus(h(x)) = 16x + 9 >= 16x + 6 = h(minus(x)) minus(f(x,y)) = 8x + 8y + 5 >= 8x + 8y + 5 = f(minus(y),minus(x)) problem: minus(f(x,y)) -> f(minus(y),minus(x)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [1 0 0] [0] [f](x0, x1) = [0 0 1]x0 + [0 0 1]x1 + [0] [0 1 0] [0 1 0] [1], [1 1 1] [minus](x0) = [0 1 1]x0 [0 1 1] orientation: [1 1 1] [1 1 1] [1] [1 1 1] [1 1 1] [0] minus(f(x,y)) = [0 1 1]x + [0 1 1]y + [1] >= [0 1 1]x + [0 1 1]y + [0] = f(minus(y),minus(x)) [0 1 1] [0 1 1] [1] [0 1 1] [0 1 1] [1] problem: Qed