2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63128We prove a conjecture of Broue about the Jordan decomposition of blocks of finite reductive groups. We show that a block of a finite connected reductive group, in non-describing characteristic, is Morita-equivalent to a quasi-isolated block of a Levi subgroup. This involves showing that some local system over a Deligne-Lusztig variety has its mod l cohomology concentrated in one degree. We reduce this question to a question about tamely ramified local systems by proving that the category of perfect complexes for the group is generated by the images of the Deligne-Lusztig functors. Then, we describe the ramification at infinity of local systems associated to characters of tori.54 pages, FrenchRepresentation Theory20G40Categories derivees et varietes de Deligne-Lusztigtext