2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/43020The current status of theoretical QCD calculations and experimental measurements of the Gottfried sum rule are discussed. The interesting from our point of view opened problems are summarised. Among them is the task of estimating the measure of light-quark flavour asymmetry in possible future experiments.8 pages, based on the talk at the 11th Lomonosov Conference on Elementary Particle Physics, 21-27 August, Moscow State University, Moscow, RussiaHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext