R. Yuan, EXISTENCE OF ALMOST-PERIODIC SOLUTIONS OF 2ND-ORDER NEUTRAL DELAY-DIFFERENTIAL EQUATIONS WITH PIECEWISE-CONSTANT ARGUMENT, Science in China. Series A, Mathematics, Physics, Astronomy & Technological Sciences, 41(3), 1998, pp. 232-241
By constructing almost periodic sequence solutions to difference equat
ions, the existence of almost periodic solutions of neutral delay diff
erential equations with piecewise constant argument d(2)/dt(2)(x(t) px(t-1)) = qx(2[t+1/2]) + g(t,x(t),x([t])). is studied.