This paper was removed due to an error in the proof (Claim 4.12 as stated is not true). The authors would like to thank Ilya Volkovich for pointing out a counterexample to this paper’s main result in positive characteristic: If F is a field with prime characteristic p, then the polynomialxp1+xp2++xpn has the following factor:(x1+x2++xn)p−1, which has sparsity np.