Enumeration of Basic Ideals in Type B Lie Algebras
Department of Mathematics
P. O. Box 480
SE-751 06, Uppsala
The number of ad-nilpotent ideals of the Borel subalgebra of the
classical Lie algebra of type Bn is determined
using combinatorial arguments involving a generalization of Dyck-paths.
We also solve a similar problem for the untwisted affine Lie algebra of
type Bn, where we instead enumerate a certain
class of ideals called basic ideals. This leads to an explicit formula
for the number of basic ideals in Bn, which
gives rise to a new integer sequence.
Full version: pdf,
Received April 17 2012;
revised versions received August 15 2012; November 17 2012.
Published in Journal of Integer Sequences, November 20 2012.
Journal of Integer Sequences home page