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Related papers: Homogeneous para-K\"ahler Einstein manifolds

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Let (J,g) be a Hermitian structure on a compact nilmanifold M with invariant complex structure J and compatible metric g, which is not required to be invariant. We give classifications of 6-dimensional nilmanifolds M admitting strong…

Differential Geometry · Mathematics 2007-05-23 Luis Ugarte

Let $(M^n, g)$ be a complete non-compact K\"ahler manifold with non-negative and bounded holomorphic bisectional curvature. We prove that $M$ is holomorphically covered by a pseudoconvex domain in $\C^n$ which is homeomorphic to $\R^{2n}$,…

Differential Geometry · Mathematics 2007-08-21 Albert Chau , Luen-Fai Tam

We give an overview of progress on homogeneous Einstein metrics on large classes of homogeneous manifolds, such as generalized flag manifolds and Stiefel manifolds. The main difference between these two classes of homogeneous spaces is that…

Differential Geometry · Mathematics 2016-05-20 Andreas Arvanitoyeorgos

We show that the pseudo-Riemannian geometry of submanifolds can be formulated in terms of higher order multi-linear maps. In particular, we obtain a Poisson bracket formulation of almost (para-)K\"ahler geometry.

Differential Geometry · Mathematics 2015-06-18 Joakim Arnlind , Gerhard Huisken

We study symmetry properties of quaternionic K\"ahler manifolds obtained by the HK/QK correspondence. To any Lie algebra $\mathfrak{g}$ of infinitesimal automorphisms of the initial hyper-K\"ahler data we associate a central extension of…

Differential Geometry · Mathematics 2021-02-15 V. Cortés , A. Saha , D. Thung

For a Lie group $G$ and a closed Lie subgroup $H\subset G$, it is well known that the coset space $G/H$ can be equipped with the structure of a manifold homogeneous under $G$ and that any $G$-homogeneous manifold is isomorphic to one of…

Differential Geometry · Mathematics 2008-11-18 E. G. Vishnyakova

An {\em almost p-K\"ahler manifold} is a triple $(M,J,\Omega)$, where $(M,J)$ is an almost complex manifold of real dimension $2n$ and $\Omega$ is a closed real tranverse $(p,p)$-form on $(M,J)$, where $1\leq p\leq n$. When $J$ is…

Differential Geometry · Mathematics 2021-09-24 Richard Hind , Costantino Medori , Adriano Tomassini

We classify invariant almost complex structures on homogeneous manifolds of dimension 6 with semi-simple isotropy. Those with non-degenerate Nijenhuis tensor have the automorphism group of dimension either 14 or 9. An invariant almost…

Differential Geometry · Mathematics 2014-02-13 Dmitri V. Alekseevsky , Boris Kruglikov , Henrik Winther

Let $(M, g)$ be a compact real analytic Riemannian manifold and $\pi \colon \widetilde{M} \to M$ its universal cover. Assume that $\widetilde{M}$ can be realised as a manifold definable in an o-minimal structure $\Sigma$ expanding…

Differential Geometry · Mathematics 2024-01-17 Vasily Rogov

We answer in the affirmative the question posed by Conti and Rossi on the existence of nilpotent Lie algebras of dimension 7 with an Einstein pseudo-metric of nonzero scalar curvature. Indeed, we construct a left-invariant pseudo-Riemannian…

Differential Geometry · Mathematics 2020-08-07 Marisa Fernández , Marco Freibert , Jonatan Sánchez

Given compact Lie groups H\subset G, we study the space of G-invariant metrics on G/H with nonnegative sectional curvature. For an intermediate subgroup K between H and G, we derive conditions under which enlarging the Lie algebra of K…

Differential Geometry · Mathematics 2008-06-24 Lorenz Schwachhofer , Kristopher Tapp

We study the class $\mathcal{K}_{2}+\mathcal{K}_{4}$ of homogeneous pseudo-K\"ahler structures in the strongly degenerate case. The local form and the holonomy of a pseudo-K\"ahler manifold admitting such a structure is obtained, leading to…

Differential Geometry · Mathematics 2012-08-03 M. Castrillón López , I. Luján

We obtain a class of Kaehler Einstein structures on the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained class of Kaehler Einstein structure depends on one essential parameter, cannot…

Differential Geometry · Mathematics 2007-05-23 Dumitru Daniel Porosniuc

This paper is devoted to the study of geometric structures modeled on homogeneous spaces G/P, where G is a real or complex semisimple Lie group and $P\subset G$ is a parabolic subgroup. We use methods from differential geometry and very…

Differential Geometry · Mathematics 2007-05-23 Andreas Cap , Jan Slovak , Vladimir Soucek

Suppose $G$ is a connected complex Lie group and $H$ is a closed complex subgroup such that $X := G/H$ is Kaehler and the codimension of the top non-vanishing homology group of $X$ with coefficients in $\mathbb Z_2$ is less than or equal to…

Complex Variables · Mathematics 2016-12-30 Seyed Ruhallah Ahmadi , Bruce Gilligan

Given a compact symplectic toric manifold $(M,\omega, \mathbb{T})$, we identify a class $DGK_{\omega}^{\mathbb{T}}(M)$ of $\mathbb{T}$-invariant generalized K\"ahler structures for which a generalisation the Abreu-Guillemin theory of toric…

Differential Geometry · Mathematics 2015-09-28 Laurence Boulanger

We study an odd-dimensional analogue of the Goldberg conjecture for compact Einstein almost K\"ahler manifolds. We give an explicit non-compact example of an Einstein almost cok\"ahler manifold that is not cok\"ahler. We prove that compact…

Differential Geometry · Mathematics 2016-01-11 Diego Conti , Marisa Fernández

We obtain a class of locally symetric Kaehler Einstein structures on the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained class of Kaehler Einstein structures depends on one essential…

Differential Geometry · Mathematics 2007-05-23 D. D. Porosniuc

In this article, we study compactifications of homogeneous spaces coming from equivariant, open embeddings into a generalized flag manifold $G/P$. The key to this approach is that in each case $G/P$ is the homogeneous model for a parabolic…

Differential Geometry · Mathematics 2021-08-04 Andreas Cap , A. Rod Gover , Matthias Hammerl

We find new conditions that the existence of nullity of the curvature tensor of an irreducible homogeneous space $M=G/H$ imposes on the Lie algebra $\mathfrak g$ of $G$ and on the Lie algebra $\tilde{\mathfrak g}$ of the full isometry group…

Differential Geometry · Mathematics 2022-07-06 Antonio J. Di Scala , Carlos E. Olmos , Francisco Vittone