Copyright © 2009 Li Wang and Chuanyi Zhang. 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.
The spectrum containment of almost
periodic solution of second-order neutral delay differential
equations with piecewise constant of argument (EPCA, for short) of
the form is considered. The main result obtained in this paper is different from that given by
some authors for ordinary differential equations (ODE, for short)
and clearly shows the differences between ODE and EPCA. Moreover, it
is also different from that given for equation because of the difference between