
It is shown that \[ x'(t)= ax(t)+ \sum^N_{j=-N} a_j x([t+ j])+ f(t)\tag{\(*\)} \] has a unique quasiperiodic (qp) solution \(x\in QP(\omega_1,\dots, \omega_r)\) whenever \(f\in QP(\omega_1,\dots, \omega_r):= \{g:\mathbb{R}\to \mathbb{R}: g\) qp with (rationally independent) frequencies \(\omega_1,\dots, \omega_r\) and absolutely convergent Fourier series\}, provided suitably defined eigenvalues \(\mu\) satisfy \(|\mu|\neq 1\). It is stated that even for periodic \(f\) there need not exist a periodic solution. The result is extended to small nonlinear qp perturbations of \((*)\).
Almost and pseudo-almost periodic solutions to functional-differential equations, quasiperiodic solution, quasi-periodic sequences, Applied Mathematics, piecewise constant argument, quasi-periodic solutions, Classical almost periodic functions, mean periodic functions, difference-differential equation, Analysis
Almost and pseudo-almost periodic solutions to functional-differential equations, quasiperiodic solution, quasi-periodic sequences, Applied Mathematics, piecewise constant argument, quasi-periodic solutions, Classical almost periodic functions, mean periodic functions, difference-differential equation, Analysis
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