J. Michel

activity

20002005

collaborators

5 papers

math.RT2005

Endomorphisms of Deligne-Lusztig varieties

François Digne, Jean Michel

This paper is a following to math.RT/0410454. For a finite group of Lie type we study the endomorphisms, commuting with the group action, of a Deligne-Lusztig variety associated to…

math.AG2004

Hurwitz action on tuples of Euclidean reflections

Jean Michel

We show that if a tuple of Euclidean reflections has a finite orbit under the Hurwitz action of the Artin braid group, then the group generated by these reflections is finite. Hump…

math.GR2003

Explicit presentations for exceptional braid groups

David Bessis, Jean Michel

We give presentations for the braid groups associated with the complex reflection groups $G_{24}$ and $G_{27}$ . For the cases of $G_{29}$ , $G_{31}$ , $G_{33}$ and $G_{34}$ , we give…

math.GR2002

The space of unipotently supported class functions on a finite reductive group

F. Digne, G. Lehrer, J. Michel

We determine the Lusztig restrictions on the space of class functions with a unipotent support on a finite reductive group. In particular we give a simple expression for the Luszti…

math.GR2000

Springer theory in braid groups and the Birman-Ko-Lee monoid

David Bessis, Francois Digne, Jean Michel

We state a conjecture about centralizers of certain roots of central elements in braid groups, and check it for Artin braid groups and some other cases. Our proof makes use of resu…