On the asymptotic behaviour of solutions of inhomogeneous linear neutral functional differential equations (Q1879169)

Consider the neutral functional-differential equation \[ \frac {d}{dt} Dx_t= Lx_t+ f(t), \tag{1} \] where \(D\) and \(L\) are bounded linear operators from \(C([-r,0], \mathbb{C}^n)\) into \(\mathbb{C}^n\), \(f\) is an almost-periodic function. The authors announce a sufficient condition for (1) to have an almost-periodic solution.