2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/154882Keller introduced a notion of quotient of a differential graded category modulo a full differential graded subcategory which agrees with Verdier's notion of quotient of a triangulated category modulo a triangulated subcategory. This work is an attempt to further develop his theory. More than a half of the text is devoted to an overview of "well known" definitions and results. As a result, the e-print is essentially self-contained.50 pages, Latex; an error in the proof of Lemma 13.5 is correctedK-Theory and HomologyAlgebraic GeometryAlgebraic TopologyCategory Theorytext