scholarly journals INVARIANT EINSTEIN METRICS ON GENERALIZED FLAG MANIFOLDS WITH TWO ISOTROPY SUMMANDS

2011 ◽  
Vol 90 (2) ◽  
pp. 237-251 ◽  
Author(s):  
ANDREAS ARVANITOYEORGOS ◽  
IOANNIS CHRYSIKOS
Keyword(s):  
Variational Approach ◽  
Einstein Metrics ◽  
Flag Manifold ◽  
Flag Manifolds ◽  
Semisimple Lie Group ◽  
Generalized Flag Manifolds ◽  
Generalized Flag Manifold ◽  
Scalar Curvature Functional ◽  
Homogeneous Einstein Metrics ◽  
Adjoint Orbit

AbstractLet M=G/K be a generalized flag manifold, that is, an adjoint orbit of a compact, connected and semisimple Lie group G. We use a variational approach to find non-Kähler homogeneous Einstein metrics for flag manifolds with two isotropy summands. We also determine the nature of these Einstein metrics as critical points of the scalar curvature functional under fixed volume.

scholarly journals HOMOGENEOUS EINSTEIN METRICS ON GENERALIZED FLAG MANIFOLDS WITH FIVE ISOTROPY SUMMANDS

2013 ◽  
Vol 24 (10) ◽  
pp. 1350077 ◽  
Author(s):  
ANDREAS ARVANITOYEORGOS ◽  
IOANNIS CHRYSIKOS ◽  
YUSUKE SAKANE
Keyword(s):  
Einstein Equation ◽  
Einstein Metrics ◽  
Flag Manifold ◽  
Polynomial Systems ◽  
Flag Manifolds ◽  
Isotropy Representation ◽  
Generalized Flag Manifolds ◽  
A New Technique ◽  
Kähler Einstein Metrics ◽  
Homogeneous Einstein Metrics

We construct the homogeneous Einstein equation for generalized flag manifolds G/K of a compact simple Lie group G whose isotropy representation decomposes into five inequivalent irreducible Ad (K)-submodules. To this end, we apply a new technique which is based on a fibration of a flag manifold over another such space and the theory of Riemannian submersions. We classify all generalized flag manifolds with five isotropy summands, and we use Gröbner bases to study the corresponding polynomial systems for the Einstein equation. For the generalized flag manifolds E6/(SU(4) × SU(2) × U(1) × U(1)) and E7/(U(1) × U(6)) we find explicitly all invariant Einstein metrics up to isometry. For the generalized flag manifolds SO (2ℓ + 1)/( U (1) × U (p) × SO (2(ℓ - p - 1) + 1)) and SO (2ℓ)/( U (1) × U (p) × SO (2(ℓ - p - 1))) we prove existence of at least two non-Kähler–Einstein metrics. For small values of ℓ and p we give the precise number of invariant Einstein metrics.

scholarly journals Berezin quantization on generalized flag manifolds

2009 ◽  
Vol 105 (1) ◽  
pp. 66 ◽  
Author(s):  
Benjamin Cahen
Keyword(s):  
Holomorphic Functions ◽  
Flag Manifold ◽  
Unitary Irreducible Representation ◽  
Flag Manifolds ◽  
Dense Open Subset ◽  
Generalized Flag Manifolds ◽  
Berezin Quantization ◽  
Generalized Flag Manifold ◽  
Simply Connected ◽  
Connected Lie Group

Let $M=G/H$ be a generalized flag manifold where $G$ is a compact, connected, simply-connected Lie group with Lie algebra $\mathfrak{g}$ and $H$ is the centralizer of a torus. Let $\pi$ be a unitary irreducible representation of $G$ which is holomorphically induced from a character of $H$. Using a complex parametrization of a dense open subset of $M$, we realize $\pi$ on a Hilbert space of holomorphic functions. We give explicit expressions for the differential $d\pi$ of $\pi$ and for the Berezin symbols of $\pi (g)$ ($g\in G$) and $d\pi (X)$ ($X\in \mathfrak{g}$). In particular, we recover some results of S. Berceanu and we partially generalize a result of K. H. Neeb.

scholarly journals Invariant Einstein metrics on generalized flag manifolds of $Sp(n)$ and $SO(2n)$

2018 ◽  
Vol 38 (1) ◽  
pp. 227
Author(s):  
Luciana Aparecida Alves ◽  
Neiton Pereira da Silva
Keyword(s):  
Einstein Equation ◽  
Algebraic System ◽  
Einstein Metrics ◽  
Flag Manifold ◽  
Flag Manifolds ◽  
Invariant Metric ◽  
Generalized Flag Manifolds

It is well known that the Einstein equation on a Riemannian flag manifold $(G/K,g)$ reduces to an algebraic system if $g$ is a $G$-invariant metric. In this paper we obtain explicitly new invariant Einstein metrics on generalized flag manifolds of $Sp(n)$ and $SO(2n)$; and we compute the Einstein system for generalized flag manifolds of type $Sp(n)$. We also consider the isometric problem for these Einstein metrics.

scholarly journals New homogeneous Einstein metrics on quaternionic Stiefel manifolds

2018 ◽  
Vol 18 (4) ◽  
pp. 509-524 ◽  
Author(s):  
Andreas Arvanitoyeorgos ◽  
Yusuke Sakane ◽  
Marina Statha
Keyword(s):  
Homogeneous Space ◽  
Einstein Metrics ◽  
Flag Manifold ◽  
Total Space ◽  
Stiefel Manifold ◽  
Isotropy Representation ◽  
Stiefel Manifolds ◽  
Generalized Flag Manifold ◽  
Generalized Wallach Space ◽  
Homogeneous Einstein Metrics

Abstract We consider invariant Einstein metrics on the quaternionic Stiefel manifold Vpℍn of all orthonormal p-frames in ℍn. This manifold is diffeomorphic to the homogeneous space Sp(n)/Sp(n − p) and its isotropy representation contains equivalent summands. We obtain new Einstein metrics on Vpℍn ≅ Sp(n)/Sp(n − p), where n = k1 + k2 + k3 and p = n − k3. We view Vpℍn as a total space over the generalized Wallach space Sp(n)/(Sp(k1)×Sp(k2)×Sp(k3)) and over the generalized flag manifold Sp(n)/(U(p)×Sp(n − p)).

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