2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59712In this paper we consider a robust identification problem for a linear dynamical control system with limited-frequency intervals. In mathematical terms, this is the problem of recovering functions in Hardy spaces. Our purpose is to bound Patil's approximants in the upper half plane case, out of a bounded real interval $I$. To this end, we deal with residu techniques and give a class of functions to provide boundedness of these approximants on the complement of this interval.15 pages, 1 figure, thesisComplex VariablesOptimization and Control30D55,30E20,44A15text