2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/4354Based on solutions of the Stewart-Lyth inverse problem it is argued that in the CMB data analysis the parametrization of the primordial spectra from inflation must include the `running' of both, scalar and tensorial, spectral indices if information beyond the exponential potential model is wanted to be detected.To appear in the Proceedings of the ``1st Mexican Meeting on Mathematical and Experimental Physics", El Colegio Nacional, Mexico City, September, 2001. 8 pages, uses kapproc.clsAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext