Springer fiber components in the two columns case for types A and D are normal
arXiv:0907.0607
Abstract
We study the singularities of the irreducible components of the Springer fiber over a nilpotent element N with N^2=0 in a Lie algebra of type A or D (the so-called two columns case). We use Frobenius splitting techniques to prove that these irreducible components are normal, Cohen-Macaulay, and have rational singularities.
v1: 18 pages; v2: 20 pages, Sec.3 rewritten, mistake in Prop.3.10 corrected