2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50656We discuss the recent proposal that BPS D-branes in Calabi-Yau compactification of type II string theory are Pi-stable objects in the derived category of coherent sheaves.amslatex, 17 pp. To appear in the proceedings of Strings 2001, Mumbai, IndiaHigh Energy Physics - Theorytext