To motivate our result, consider Newton’s method N for solving the equationf(z) = 0, wheref is a complex polynomial, f(z) = X$0 aizi. We write N: 5$ X S + S, where Z& is the space of polynomials of degree %d and S is the Riemann sphere C U ~0. Then N(f, z) = Nf(z) = z f(z)/f’(z) is rational over C inf and z; that is, N can be formed from the complex rational operations (+ , , x , +) from the co...