2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76500These notes are based on the lecture courses given at the Ruhr-Universit{ä}t-Bochum (03--08.02.1997) and at the Universit{é} Paul Sabatier (Toulouse, 08-12.01.1996).Second revised version, extended. 54 Pages, LaTeXAlgebraic Geometrytext