Quasi-admissible, raisable nilpotent orbits and covering Barbasch-Vogan duality

Abstract

For simply-connected Lie groups of type E over \( p \)-adic local field \( F \), we determine the degree of the cover required for a given \( F \)-split nilpotent orbit to be quasi-admissible or raisable, respectively. Combining this result with the previously computed data for other types by Gao-Liu-Tsai, we prove that all \( F \)-split nilpotent orbits whose geometry type contained in the image of the covering Barbasch-Vogan duality map \( d_{\mathrm{BV},G}^{(n)} \) of almost-simple Lie groups \( G \) in each Cartan type are always\( \overline{G}^{(n)} \)-quasi-admissible.