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