Diffusive Representation for Operators Involving Delays

The theory of diffusive representation (DR) is essentially devoted to state-space realizations of integral operators of complex nature encountered in many concrete or theoretical situations. This approach has allowed to construct efficient solutions of non trivial problems in various fields (see [13], [9], [10]). Under their standard form, these state realizations are diffusive, which straightforwardly leads to cheap numerical approximations as well as dissipative properties useful for analysis or control purposes. This diffusive nature however imposes a restriction: the so-realized operators are pseudodifferential, which excludes in particular delay operators and so any operator involving delays.