YES Problem: add(0(),x) -> x add(s(x),y) -> s(add(x,y)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0, [add](x0, x1) = x0 + x1 + 6, [0] = 1 orientation: add(0(),x) = x + 7 >= x = x add(s(x),y) = x + y + 6 >= x + y + 6 = s(add(x,y)) problem: add(s(x),y) -> s(add(x,y)) Matrix Interpretation Processor: dim=3 interpretation: [0] [s](x0) = x0 + [1] [1], [1 0 1] [1 0 1] [add](x0, x1) = [0 1 0]x0 + [0 1 0]x1 [0 1 0] [0 0 0] orientation: [1 0 1] [1 0 1] [1] [1 0 1] [1 0 1] [0] add(s(x),y) = [0 1 0]x + [0 1 0]y + [1] >= [0 1 0]x + [0 1 0]y + [1] = s(add(x,y)) [0 1 0] [0 0 0] [1] [0 1 0] [0 0 0] [1] problem: Qed