YES Problem: f(c(s(x),y)) -> f(c(x,s(y))) g(c(x,s(y))) -> g(c(s(x),y)) g(s(f(x))) -> g(f(x)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [c](x0, x1) = 4x0 + 4x1, [g](x0) = x0 + 1, [s](x0) = x0 + 2, [f](x0) = 2x0 orientation: f(c(s(x),y)) = 8x + 8y + 16 >= 8x + 8y + 16 = f(c(x,s(y))) g(c(x,s(y))) = 4x + 4y + 9 >= 4x + 4y + 9 = g(c(s(x),y)) g(s(f(x))) = 2x + 3 >= 2x + 1 = g(f(x)) problem: f(c(s(x),y)) -> f(c(x,s(y))) g(c(x,s(y))) -> g(c(s(x),y)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [1 0 0] [c](x0, x1) = [0 1 1]x0 + [0 0 0]x1 [0 0 0] [0 0 0] , [1 0 0] [g](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [0] [s](x0) = [0 1 1]x0 + [0] [0 0 0] [1], [1 1 0] [f](x0) = [0 1 0]x0 [0 0 0] orientation: [1 1 1] [1 0 0] [1] [1 1 1] [1 0 0] f(c(s(x),y)) = [0 1 1]x + [0 0 0]y + [1] >= [0 1 1]x + [0 0 0]y = f(c(x,s(y))) [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] [1 0 0] [1 0 0] [1 0 0] [1 0 0] g(c(x,s(y))) = [0 0 0]x + [0 0 0]y >= [0 0 0]x + [0 0 0]y = g(c(s(x),y)) [0 0 0] [0 0 0] [0 0 0] [0 0 0] problem: g(c(x,s(y))) -> g(c(s(x),y)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [c](x0, x1) = [0 0 0]x0 + x1 [0 0 0] , [1 0 1] [g](x0) = [0 1 0]x0 [0 0 0] , [0] [s](x0) = x0 + [0] [1] orientation: [1 0 0] [1 0 1] [1] [1 0 0] [1 0 1] g(c(x,s(y))) = [0 0 0]x + [0 1 0]y + [0] >= [0 0 0]x + [0 1 0]y = g(c(s(x),y)) [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] problem: Qed