Certain geometric function
theory results are obtained for holomorphic mappings on the unit ball. Specifically,
the mappings studied are one-to-one onto domains that are starlike with respect to
the origin. For such a mapping f(z), sharp estimates are derived for |f(z)| in terms of
|z|. Also, a generalization of the Koebe covering theorem is proved. As a corollary of
the work, a new proof is given that, in Cn for n ≥ 2, a ball and a polydisc are not
biholomorphically equivalent.