2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49779Various aspects of spaces of chiral blocks are discussed. In particular, conjectures about the dimensions of irreducible sub-bundles are reviewed and their relation to symmetry breaking conformal boundary conditions is outlined.18 pages, LaTeX2e; slightly extended version of contribution to the Proceedings of `Lie III' (Clausthal, July 1999)High Energy Physics - Theorytext