Derived categories and Deligne-Lusztig varieties II

By C'edric Bonnaf'e, Jean-François Dat, Raphaël Rouquier. 2015

81 citations recorded by the source corpus.

This paper is a continuation and a completion of [BoRo1]. We extend the Jordan decomposition of blocks: we show that blocks of finite groups of Lie type in non-describing characteristic are Morita equivalent to blocks of subgroups associated to isolated elements of the dual group. The key new result is the invariance of the part of the cohomology in a given modular series of Deligne-Lusztig varieties associated to a given Levi subgroup, under certain variations of parabolic subgroups. We also show that the equivalence arises from a splendid Rickard equivalence. Even in the setting of [BoRo1], the finer homotopy equivalence was unknown. As a consequence, the equivalence preserves defect groups and categories of subpairs. We finally determine when Deligne-Lusztig induced representations of tori generate the derived category of representations.

Subfields: Geometry and Topology, Mathematical Physics

View Paper: https://www.semanticscholar.org/paper/e44ec53c977712375f20645982a9b6b4ccdd6a2b

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In Geometry and Topology

1. Pham Huu Tiep
2. Gunter Malle
3. Gabriel Navarro
4. A. S. Fry
5. Britta Spath
6. Britta Spaeth
7. M. Cabanes

In Mathematical Physics

1. Gabriel Navarro
2. Pham Huu Tiep
3. A. S. Fry
4. Gunter Malle
5. Britta Spath

Citations in the corpus

• Brauer's Height Zero Conjecture (2022, background): “Then its Morita-equivalent Jordan correspondent block ˜ b 1 , of a group of order less than | G ∗ | / 3 = | ¯ S | , also has non-abelian defect by [6, Thm 1.1].”