2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41798We extract the pion fragmentation functions and their uncertainties from a judicious choice of e+e- and semi-inclusive DIS data. These are used to study the error propagation in the extraction of polarized parton densities from semi-inclusive DIS asymmetries. We conclude that the uncertainties on polarized PDs have been underestimated in the past.6 pages, 2 Figures, a talk presented by E. Leader at the X International Workshop on Deep Inelastic Scattering (DIS2002) in Krakow, 2002, PolandHigh Energy Physics - Phenomenologytext