Abelian ideals and amazing roots
Representation Theory
2017-11-15 v1
Abstract
Let be a simple Lie algebra with a Borel subalgebra . To any long positive root , one associates two ideals of : the abelian ideal and not necessarily abelian ideal . It is known that , and is said to be amazing if the equality holds. The set of amazing roots, , is closed under the operation `' in , and is said to be primitive, if it cannot be written as with incomparable amazing roots . We classify the amazing roots and notice that the number of primitive roots equals . Moreover, if (resp. ) is the set of simple (resp. primitive) roots, then there is a natural bijection . We also describe the set , where is the Heisenberg subset of .
Keywords
Cite
@article{arxiv.1711.04129,
title = {Abelian ideals and amazing roots},
author = {Dmitri I. Panyushev},
journal= {arXiv preprint arXiv:1711.04129},
year = {2017}
}
Comments
9 pages, to appear in International J. of Mathematics