4 papers
On symmetric invariants of centralisers in reductive Lie algebras
D. Panyushev, A. Premet, O. Yakimova
Let be the centraliser of a nilpotent element in a finite dimensional simple Lie algebra of rank over an algebraically closed field of characteristic 0. We invest…
(Ir)Reducibility of some commuting varieties associated with involutions
Oksana Yakimova
Here we prove that a commuting variety associated with a symmetric pair (g, g_0) is irreducible for (so_{n+m}, so_n + so_m) and reducible for (gl_{n+m}, {gl}_n + gl_m) with n>m, (s…
The index of representations associated with stabilisers
Dmitri I. Panyushev, Oksana S. Yakimova
Let be an algebraic group and a -module. The index of is the minimal codimension of the -orbits in the dual space . There is a general inequality, due to Vin…
The centralisers of nilpotent elements in classical Lie algebras
O. S. Yakimova
The index of a finite-dimensional Lie algebra is the minimum of dimensions of stabilisers of elements . Let be a reductive Lie algebra and a centrali…