Research interests

I work in modular representation theory of finite reductive groups (such as GLn(q), Sp2n(q),...). I am particularly interested in the modular Deligne-Lusztig theory and the geometric version of Broué's abelian defect group conjecture.


Published or accepted papers

Translation by the full twist and Deligne--Lusztig varieties, to appear in J. Algebra, 2019
(with C. Bonnafé and R. Rouquier).
Categorical actions on unipotent representations of finite unitary groups, Publications Mathématiques de l'IHES, 2019 (with M. Varagnolo and É. Vasserot).
Non-uniqueness of supercuspidal support for finite reductive groups. Appendix to the article Simple subquotients of big parabolically induced representations of p-adic groups by J.-F. Dat, to appear in J. Algebra, 2018
Bounding Harish-Chandra series, accepted in Transactions of the AMS, 2018 (with G. Malle).
Brauer trees of unipotent blocks, accepted in JEMS, 2018 (with D. Craven and R. Rouquier).
Alvis-Curtis duality for finite general linear groups and a generalized Mullineux involution, SIGMA 14, 2018 (with N. Jacon).
Lectures on modular Deligne-Lusztig theory, to appear in the EMS Series of Lectures in Mathematics, 2018.
Splendeur des variétés de Deligne-Lusztig, d'après Deligne-Lusztig, Broué, Rickard, Bonnafé-Dat-Rouquier, Séminaire Bourbaki, Exp. 1137, to appear in Astérisque, 2017. [You can watch the talk here]
Modular irreducibility of cuspidal unipotent characters, Invent. Math. (211), 2018, 579--589 (with G. Malle).
Categorical actions from Lusztig induction and restriction on finite general linear groups in Representation theory - current trends and perspectives, 59--74, EMS Ser. Congr. Rep., Eur. Math. Soc., Zürich, 2017 (with M. Varagnolo and É. Vasserot).
Categorical actions on unipotent representations of finite classical groups in Categorification and higher representation theory, 41--104, Contemp. Math. (683), Amer. Math. Soc., Providence, RI, 2017 (with M. Varagnolo and É. Vasserot).
Decomposition matrices for exceptional groups at d=4, J. Pure Appl. Algebra (220), 2016, pp 1096--1121 (with G. Malle).
Decomposition matrices for low rank unitary groups, Proc. London Math. Soc. (110), 2015, pp 1517--1557 (with G. Malle).
Projective modules in the intersection cohomology of Deligne--Lusztig varieties, C. R. Acad. Sci., 2014 (with G. Malle). [I gave a talk about this here]
Cohomology of Deligne-Lusztig varieties for unipotent blocks of GLn(q), Represent. Th. (17), 2013, pp 647--662.
A note on decomposition numbers for groups of Lie type of small rank , J. Algebra (388), 2013, pp 364--373.
Coxeter orbits and Brauer trees III, J. Amer. Math. Soc. (27), 2014, pp 1117--1145 (with R. Rouquier).
Cohomology of Deligne-Lusztig varieties for short-length regular elements in exceptional groups, J. Algebra (392), 2013, pp 276--298.
Quotient of Deligne-Lusztig varieties, J. Algebra (381), 2013, pp 1--20.
Coxeter orbits and Brauer trees II, Int. Math. Res. Not. (15), 2014, pp 4100--4123.
Coxeter orbits and Brauer trees, Adv. Math. (229), no. 6, 2012, pp 3398--3435.
Deligne-Lusztig restriction of a Gelfand-Graev module, Ann. Sci. Ec. Norm. Sup. (42), 2009, pp 653--674.


Categorical actions on unipotent representations of finite unitary groups, Oberwolfach report, Group theory, 2015.
Quotients of Deligne-Lusztig varieties, Oberwolfach report, Group theory, 2012.
Geometry of Deligne-Lusztig varieties, decompositions, mod \ell cohomology and modular representations, PhD thesis, 2010.
Note on the Deodhar decomposition, preprint.

Some (rather old) talks

I rarely use beamer for giving talks so this is pretty old material:

A talk about the joint work [9] with Gunter Malle.
Brauer trees of finite reductive groups via Deligne-Lusztig theory, Pohang, March 2011.
Some Slides I used during my viva, Besançon, June 2010.
Parity sheaves (with Peng Shan), Sheaves in representation theory, Isle of Skye, May 2010.
Autour des représentations linéaires des groupes finis classiques, Journées des Écoles doctorales de Besançon et Dijon, Dijon, May 09.