Published online by Cambridge University Press: 14 December 2021
We study the action of a real reductive group G on a real submanifold X of a Kähler manifold Z. We suppose that the action of a compact connected Lie group U with Lie algebra
$\mathfrak {u}$
extends holomorphically to an action of the complexified group
$U^{\mathbb {C}}$
and that the U-action on Z is Hamiltonian. If
$G\subset U^{\mathbb {C}}$
is compatible, there exists a gradient map
$\mu _{\mathfrak p}:X \longrightarrow \mathfrak p$
where
$\mathfrak g=\mathfrak k \oplus \mathfrak p$
is a Cartan decomposition of
$\mathfrak g$
. In this paper, we describe compact orbits of parabolic subgroups of G in terms of the gradient map
$\mu _{\mathfrak p}$
.
Biliotti was partially supported by the Project PRIN 2015, Real and Complex Manifolds: Geometry, Topology and Harmonic Analysis, by the Project PRIN 2017, Real and Complex Manifolds: Topology, Geometry and Holomorphic Dynamics, and by the GNSAGA INdAM.