TECHNION FACULTY OF MATHEMATICS ALGEBRA SEMINAR SPEAKER: Lucas Fresse, Hebrew U. TOPIC: Smooth orbital varieties and orbital varieties with a dense B-orbit DATE: Thursday, Jan 6, 2011 TIME: 12:30 PLACE: Amado 719 Abstract: To a nilpotent element x in a reductive Lie algebra, one can attach several algebraic varieties which play roles in geometric representation theory: its nilpotent orbit; the intersection of its nilpotent orbit with the nilradical of a Borel subalgebra (the irreducible components of this intersection are called orbital varieties); the fiber over x of the Springer resolution. There is a close relation between the Springer fiber over x and the orbital varieties attached to x. In this talk, we rely on this relation in order to study two properties of orbital varieties: the smoothness, and the property to contain a dense B-orbit. We concentrate on the type A. We provide several results which suggest that the two mentioned properties are related. This is a joint work with Anna Melnikov. <http://www.technion.ac.il/~neftind/algebra_seminar.htm> --------------------------------------------------------- Technion Math. Net (TECHMATH) Editor: Michael Cwikel <techm@math.technion.ac.il> Announcement from: Jack Sonn <sonn@math.technion.ac.il>