Copyright © 2011 Kai Liu et al. This is an open access article distributed under the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
We investigate the zeros distributions of difference polynomials of meromorphic functions, which can be viewed as the
Hayman conjecture as introduced by (Hayman 1967) for difference. And we also study the uniqueness
of difference polynomials of meromorphic functions sharing a common
value, and obtain uniqueness theorems for difference.