|VIRGINIE CHARETTE, University of Maryland, College Park, Maryland 20742, USA|
|Properly discontinuous actions of free groups on Minkowski space|
Margulis showed that free, non-abelian groups can act freely and properly discontinuously on three-dimensional Minkowski space. These examples of ``affine Schottky groups'' came as a surprise.
The talk will focus on quotients of Minkowski space by such groups of isometries that can be factored as products of inversions. Certain preferred fundamental polyhedra for their action will be introduced and facts about recurring geodesics will be presented.