Prehomogeneous spaces for the coadjoint action of a parabolic group (Q1880684)

Let \(B\) be a Borel subgroup of a reductive linear algebraic group \(G\) over an algebraically closed field. Let \(b_u\) be Lie algebra of the unipotent radical of \(B\). It was shown by \textit{A. Joseph} [J. Algebra 48, 241--289 (1977; Zbl 0405.17007)] that in characteristic zero \(B\) acts on \((b_u)^*\) with a dense orbit. The author proves that this result holds in arbitrary characteristic.