2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216474For (E) being one of the three sets: the whole real axis, a finite symmetric interval and the positive semiaxis, we discuss the simplest differential operators of the second order which commute with the truncated Fourier operator (\mathscr{F}_E).19 pagesClassical Analysis and ODEsSpectral Theory47A38, 47B35, 47B06, 47A10text