Advances in Difference Equations
Volume 2009 (2009), Article ID 143175, 14 pages
doi:10.1155/2009/143175

On the spectrum of almost periodic solution of second-order neutral delay differential equations with piecewise constant of argument

Abstract

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 (x(t)+px(t-1))′′=qx(2[(t+1)/2])+f(t) 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 (x(t)+px(t-1))′′=qx([t])+f(t) because of the difference between [t] and 2[(t+1)/2].