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