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