YES Problem: +(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0, [+](x0, x1) = x0 + x1 + 6, [0] = 1 orientation: +(0(),y) = y + 7 >= y = y +(s(x),y) = x + y + 6 >= x + y + 6 = s(+(x,y)) +(s(x),y) = x + y + 6 >= x + y + 6 = +(x,s(y)) problem: +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [+](x0, x1) = 2x0 + x1 orientation: +(s(x),y) = 2x + y + 2 >= 2x + y + 1 = s(+(x,y)) +(s(x),y) = 2x + y + 2 >= 2x + y + 1 = +(x,s(y)) problem: Qed