Parameter identifiability of differential delay equations

Parameter identifiability is concerned with the question whether the parame ters of a specific model can be identified from knowledge about certain sol utions of the model, assuming perfect data. In this paper we shall consider conditions for identifiability of parameters and time delays in infinite d imensional dynamical systems, described by linear differential delay equati ons, assuming knowledge of particular solutions on bounded time intervals. We shall show how methods from operator theory can be exploited to give nec essary and sufficient conditions which guarantee that the inverse problem h as a unique solution. Copyright (C) 2001 John Wiley & Sons, Ltd.