Copyright © 2011 Ke Li and Jin Liang. 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 monic complex-coefficient polynomial of degree in the complex variable and obtain a new annular bound
for the zeros of , which is sharper than the previous results and has clear advantages
in judging the Schur stability of difference equations. In addition, examples are given to
illustrate the theoretical result.