Second-order neutral delay-differential equations with piecewise constant time dependence

We find conditions for the existence and uniqueness of almost periodic solutions of secondorder neutral delay-differential equations with almost periodic time dependence of the form (x(t )+ px(t −1)) = qx([t ])+f (t); here [·] is the greatest integer function, p and q are nonzero constants, and f (t) is Bohr almost periodic.  2003 Elsevier Science (USA). All rights reserved