YES Problem: *(x,*(minus(y),y)) -> *(minus(*(y,y)),x) Proof: Matrix Interpretation Processor: dim=1 interpretation: [*](x0, x1) = 2x0 + 2x1 + 6, [minus](x0) = x0 + 3 orientation: *(x,*(minus(y),y)) = 2x + 8y + 30 >= 2x + 8y + 24 = *(minus(*(y,y)),x) problem: Qed