YES Problem: f(nil()) -> nil() f(.(nil(),y)) -> .(nil(),f(y)) f(.(.(x,y),z)) -> f(.(x,.(y,z))) g(nil()) -> nil() g(.(x,nil())) -> .(g(x),nil()) g(.(x,.(y,z))) -> g(.(.(x,y),z)) Proof: Matrix Interpretation Processor: dim=1 interpretation: [g](x0) = 4x0 + 5, [.](x0, x1) = x0 + x1, [f](x0) = 2x0, [nil] = 0 orientation: f(nil()) = 0 >= 0 = nil() f(.(nil(),y)) = 2y >= 2y = .(nil(),f(y)) f(.(.(x,y),z)) = 2x + 2y + 2z >= 2x + 2y + 2z = f(.(x,.(y,z))) g(nil()) = 5 >= 0 = nil() g(.(x,nil())) = 4x + 5 >= 4x + 5 = .(g(x),nil()) g(.(x,.(y,z))) = 4x + 4y + 4z + 5 >= 4x + 4y + 4z + 5 = g(.(.(x,y),z)) problem: f(nil()) -> nil() f(.(nil(),y)) -> .(nil(),f(y)) f(.(.(x,y),z)) -> f(.(x,.(y,z))) g(.(x,nil())) -> .(g(x),nil()) g(.(x,.(y,z))) -> g(.(.(x,y),z)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 1] [g](x0) = [0 1 0]x0 [1 0 1] , [1 0 0] [1 1 0] [0] [.](x0, x1) = [0 0 0]x0 + [0 0 0]x1 + [1] [0 1 1] [0 0 1] [0], [1 0 1] [f](x0) = [0 1 0]x0 [1 0 1] , [0] [nil] = [0] [1] orientation: [1] [0] f(nil()) = [0] >= [0] = nil() [1] [1] [1 1 1] [1] [1 1 1] [0] f(.(nil(),y)) = [0 0 0]y + [1] >= [0 0 0]y + [1] = .(nil(),f(y)) [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 1] [1] f(.(.(x,y),z)) = [0 0 0]x + [0 0 0]y + [0 0 0]z + [1] >= [0 0 0]x + [0 0 0]y + [0 0 0]z + [1] = f(.(x,.(y,z))) [1 1 1] [1 1 1] [1 1 1] [1] [1 1 1] [1 1 1] [1 1 1] [1] [1 1 1] [1] [1 0 1] [0] g(.(x,nil())) = [0 0 0]x + [1] >= [0 0 0]x + [1] = .(g(x),nil()) [1 1 1] [1] [1 1 1] [1] [1 1 1] [1 1 1] [1 1 1] [1] [1 1 1] [1 1 1] [1 1 1] [1] g(.(x,.(y,z))) = [0 0 0]x + [0 0 0]y + [0 0 0]z + [1] >= [0 0 0]x + [0 0 0]y + [0 0 0]z + [1] = g(.(.(x,y),z)) [1 1 1] [1 1 1] [1 1 1] [1] [1 1 1] [1 1 1] [1 1 1] [1] problem: f(.(.(x,y),z)) -> f(.(x,.(y,z))) g(.(x,.(y,z))) -> g(.(.(x,y),z)) Matrix Interpretation Processor: dim=3 interpretation: [1 1 0] [g](x0) = [0 0 0]x0 [0 1 0] , [1 1 1] [1 0 0] [0] [.](x0, x1) = [0 0 0]x0 + [0 1 1]x1 + [0] [0 0 0] [0 0 0] [1], [1 0 0] [f](x0) = [0 0 0]x0 [0 0 0] orientation: [1 1 1] [1 1 1] [1 0 0] [1] [1 1 1] [1 1 1] [1 0 0] f(.(.(x,y),z)) = [0 0 0]x + [0 0 0]y + [0 0 0]z + [0] >= [0 0 0]x + [0 0 0]y + [0 0 0]z = f(.(x,.(y,z))) [0 0 0] [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] [0 0 0] [1 1 1] [1 1 1] [1 1 1] [1] [1 1 1] [1 1 1] [1 1 1] [1] g(.(x,.(y,z))) = [0 0 0]x + [0 0 0]y + [0 0 0]z + [0] >= [0 0 0]x + [0 0 0]y + [0 0 0]z + [0] = g(.(.(x,y),z)) [0 0 0] [0 0 0] [0 1 1] [1] [0 0 0] [0 0 0] [0 1 1] [0] problem: g(.(x,.(y,z))) -> g(.(.(x,y),z)) Matrix Interpretation Processor: dim=1 interpretation: [g](x0) = 2x0 + 1, [.](x0, x1) = x0 + 2x1 + 4 orientation: g(.(x,.(y,z))) = 2x + 4y + 8z + 25 >= 2x + 4y + 4z + 17 = g(.(.(x,y),z)) problem: Qed