YES Problem: strict: f(c(s(x),y)) -> f(c(x,s(y))) f(c(s(x),s(y))) -> g(c(x,y)) g(c(x,s(y))) -> g(c(s(x),y)) g(c(s(x),s(y))) -> f(c(x,y)) weak: rand(x) -> x rand(x) -> rand(s(x)) Proof: Matrix Interpretation Processor: dim=2 interpretation: [1 0] [2] [rand](x0) = [0 2]x0 + [0], [1 0] [0] [c](x0, x1) = x0 + [0 0]x1 + [2], [2 1] [g](x0) = [0 1]x0, [s](x0) = x0, [2 1] [f](x0) = [0 1]x0 orientation: [2 1] [2 0] [2] [2 1] [2 0] [2] f(c(s(x),y)) = [0 1]x + [0 0]y + [2] >= [0 1]x + [0 0]y + [2] = f(c(x,s(y))) [2 1] [2 0] [2] [2 1] [2 0] [2] f(c(s(x),s(y))) = [0 1]x + [0 0]y + [2] >= [0 1]x + [0 0]y + [2] = g(c(x,y)) [2 1] [2 0] [2] [2 1] [2 0] [2] g(c(x,s(y))) = [0 1]x + [0 0]y + [2] >= [0 1]x + [0 0]y + [2] = g(c(s(x),y)) [2 1] [2 0] [2] [2 1] [2 0] [2] g(c(s(x),s(y))) = [0 1]x + [0 0]y + [2] >= [0 1]x + [0 0]y + [2] = f(c(x,y)) [1 0] [2] rand(x) = [0 2]x + [0] >= x = x [1 0] [2] [1 0] [2] rand(x) = [0 2]x + [0] >= [0 2]x + [0] = rand(s(x)) problem: strict: f(c(s(x),y)) -> f(c(x,s(y))) f(c(s(x),s(y))) -> g(c(x,y)) g(c(x,s(y))) -> g(c(s(x),y)) g(c(s(x),s(y))) -> f(c(x,y)) weak: rand(x) -> rand(s(x)) Matrix Interpretation Processor: dim=2 interpretation: [2 0] [0] [rand](x0) = [0 0]x0 + [2], [2 1] [2 1] [1] [c](x0, x1) = [0 0]x0 + [2 0]x1 + [0], [1 0] [g](x0) = [0 0]x0, [0] [s](x0) = x0 + [1], [1 0] [f](x0) = [0 0]x0 orientation: [2 1] [2 1] [2] [2 1] [2 1] [2] f(c(s(x),y)) = [0 0]x + [0 0]y + [0] >= [0 0]x + [0 0]y + [0] = f(c(x,s(y))) [2 1] [2 1] [3] [2 1] [2 1] [1] f(c(s(x),s(y))) = [0 0]x + [0 0]y + [0] >= [0 0]x + [0 0]y + [0] = g(c(x,y)) [2 1] [2 1] [2] [2 1] [2 1] [2] g(c(x,s(y))) = [0 0]x + [0 0]y + [0] >= [0 0]x + [0 0]y + [0] = g(c(s(x),y)) [2 1] [2 1] [3] [2 1] [2 1] [1] g(c(s(x),s(y))) = [0 0]x + [0 0]y + [0] >= [0 0]x + [0 0]y + [0] = f(c(x,y)) [2 0] [0] [2 0] [0] rand(x) = [0 0]x + [2] >= [0 0]x + [2] = rand(s(x)) problem: strict: f(c(s(x),y)) -> f(c(x,s(y))) g(c(x,s(y))) -> g(c(s(x),y)) weak: rand(x) -> rand(s(x)) Matrix Interpretation Processor: dim=2 interpretation: [1 0] [2] [rand](x0) = [0 0]x0 + [0], [1 0] [c](x0, x1) = x0 + [1 0]x1, [2 0] [3] [g](x0) = [2 0]x0 + [0], [1 0] [0] [s](x0) = [1 1]x0 + [2], [1 1] [f](x0) = [0 0]x0 orientation: [2 1] [2 0] [2] [1 1] [2 0] f(c(s(x),y)) = [0 0]x + [0 0]y + [0] >= [0 0]x + [0 0]y = f(c(x,s(y))) [2 0] [2 0] [3] [2 0] [2 0] [3] g(c(x,s(y))) = [2 0]x + [2 0]y + [0] >= [2 0]x + [2 0]y + [0] = g(c(s(x),y)) [1 0] [2] [1 0] [2] rand(x) = [0 0]x + [0] >= [0 0]x + [0] = rand(s(x)) problem: strict: g(c(x,s(y))) -> g(c(s(x),y)) weak: rand(x) -> rand(s(x)) Matrix Interpretation Processor: dim=2 interpretation: [2 0] [0] [rand](x0) = [0 0]x0 + [1], [1 0] [c](x0, x1) = [0 0]x0 + x1, [2 1] [g](x0) = [1 1]x0, [1 0] [0] [s](x0) = [0 2]x0 + [2] orientation: [2 0] [2 2] [2] [2 0] [2 1] g(c(x,s(y))) = [1 0]x + [1 2]y + [2] >= [1 0]x + [1 1]y = g(c(s(x),y)) [2 0] [0] [2 0] [0] rand(x) = [0 0]x + [1] >= [0 0]x + [1] = rand(s(x)) problem: strict: weak: rand(x) -> rand(s(x)) Qed