Glorious pairs of roots and Abelian ideals of a Borel subalgebra

Dmitri I. Panyushev

Let $\mathfrak{g}$ be a simple Lie algebra with a Borel subalgebra $\mathfrak{b}$. Let ${\Delta }^{+}$ be the corresponding (po)set of positive roots and $\theta$ the highest root. A pair $\{η,η'\}…