Second-order neutral delay-differential equations with piecewise constant time dependence. (Q1399292)

The author establishes conditions for the existence and uniqueness of almost-periodic solutions to second-order neutral delay-differential equations with almost-periodic time dependence of the form \[ (x(t)+px(t-1))''=qx([t])+f(t), \] where \([\, \cdot \,]\) is the greatest integer function, \(p\) and \(q\) are nonzero constants, and \(f\) is Bohr almost-periodic.