Computing with polynomials given by straight-line programs II sparse factorization

We develop an algorithm for the factorization of a multivariate polynomial represented by a straight-line program into its irreducible factors represented as sparse polynomials. Our algorithm is in random polynomial-time for the usual coefficient fields and outputs with controllably high probability the correct factorization. It only requires an a priori bound for the total degree of the input and over rational numbers a bound on the size of the polynomial coefficients.