We study in this paper the jet schemes of the closure of nilpotent orbits in a
finite-dimensional complex reductive Lie algebra. For the nilpotent cone,
which is the closure of the regular nilpotent orbit, all the jet schemes are
irreducible. This was first observed by Eisenbud and Frenkel, and follows
from a strong result of Mustaţă (2001). Using induction and restriction of
“little” nilpotent orbits in reductive Lie algebras, we show that for a large
number of nilpotent orbits, the jet schemes of their closures are reducible. As a
consequence, we obtain certain geometric properties of these nilpotent orbit
closures.
Laboratoire de Mathématiques et
Applications
Universite de Poitiers
Teéléport 2 - BP 30179
Boulevard Marie et Pierre Curie
86962 Futuroscope (Poitiers) Chasseneuil Cedex
France
Laboratoire de Mathématiques de
Reims (LMR) - EA 4535
Université de Reims Champagne Ardenne
U.F.R. Sciences Exactes et Naturelles
Moulin de la Housse - BP 1039
51687 Reims Cedex 2
France