2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76189We show that the usual Mikhlin multiplier theorem relative to the distorted Fourier transform holds in the range (3/2,3) at least for radial functions and potentials. The restricted range is due to the fact that the Schroedinger operator which gives rise to the distorted Fourier transform may have a zero energy resonance. Consequently, the Littlewood-Paley theorem is shown also only for the range (3/2,3).Classical Analysis and ODEsMathematical Physics34L25, 42A45text