YES Problem: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [c](x0) = 4x0 + 2, [f](x0, x1) = 4x0 + 2x1, [s](x0) = 2x0 orientation: f(s(x),y) = 8x + 2y >= 8x = f(x,s(x)) f(x,s(y)) = 4x + 4y >= 2x + 4y = f(y,x) f(c(x),y) = 16x + 2y + 8 >= 8x = f(x,s(x)) problem: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) Matrix Interpretation Processor: dim=1 interpretation: [f](x0, x1) = 2x0 + x1, [s](x0) = 2x0 + 4 orientation: f(s(x),y) = 4x + y + 8 >= 4x + 4 = f(x,s(x)) f(x,s(y)) = 2x + 2y + 4 >= x + 2y = f(y,x) problem: Qed