Almost periodic solutions of second-order neutral delay-differential equations with piecewise constant arguments

In this paper, we present an existence theorem of almost periodic solutions of second-order neutral delay-differential equations with piecewise constant arguments of the form (x(t)+x(t−1))″=qx(t])+f(t), where ·] denotes the greatest integer function, q is a nonzero constant, and f(t) is almost periodic.