2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/98996A new section on projections of coherent sheaves from a projective space to a lower-dimensional projective space has been added. Also some of the notation has been altered to bring it into line with the joint paper with Eisenbud and Schreyer.AMSLatex, 67 pagesAlgebraic Geometry14F05 (Primary) 14Q99, 16E05 (Secondary)Describing coherent sheaves on projective spaces via Koszul dualitytext