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We introduce the notion of abelian almost contact structures on an odd dimensional real Lie algebra $\mathfrak g$. This a sufficient condition for the structure to be normal. We investigate correspondences with even dimensional real Lie…

Differential Geometry · Mathematics 2020-07-01 Adrian Andrada , Giulia Dileo

Let L\subset V=\bR^{k,l} be a maximally isotropic subspace. It is shown that any simply connected Lie group with a bi-invariant flat pseudo-Riemannian metric of signature (k,l) is 2-step nilpotent and is defined by an element \eta \in…

Differential Geometry · Mathematics 2009-08-03 Vicente Cortés , Lars Schäfer

The classification of Riemannian manifolds by the holonomy group of their Levi-Civita connection picks out many interesting classes of structures, several of which are solutions to the Einstein equations. The classification has two parts.…

Differential Geometry · Mathematics 2007-05-23 Richard Cleyton , Andrew Swann

A Riemannian manifold $(M,\rho)$ is called Einstein if the metric $\rho$ satisfies the condition $\Ric (\rho)=c\cdot \rho$ for some constant $c$. This paper is devoted to the investigation of $G$-invariant Einstein metrics with additional…

Differential Geometry · Mathematics 2015-11-26 Andreas Arvanitoyeorgos , V. V. Dzhepko , YU. G. Nikonorov

In this article, we study Einstein Kropina metrics on Lie groups and homogeneous spaces. We give a method to construct Einstein Kropina metrics on Lie groups. As an example of this method, a family of non-Riemannian Einstein Kropina metrics…

Differential Geometry · Mathematics 2024-07-23 Masoumeh Hosseini , Hamid Reza Salimi Moghaddam

In this note we give an explicit construction of Sasaki-Einstein metrics on a class of simply connected 7-manifolds with the rational cohomology of the 2-fold connected sum of $S^2\times S^5$. The homotopy types are distinguished by torsion…

Differential Geometry · Mathematics 2019-06-18 Charles P. Boyer , Christina Tønnesen-Friedman

In this paper we provide a local construction of a Sasakian manifold given a K\"ahler manifold. Obatined in this way manifold we call Sasakian lift of K\"ahler base. Almost contact metric structure is determined by the operation of the lift…

Differential Geometry · Mathematics 2023-03-24 Piotr Dacko

In this article we study the stability problem for the Einstein metrics on Sasaki Einstein and on complete nearly parallel ${\rm G}_2$ manifolds. In the Sasaki case we show linear instability if the second Betti number is positive.…

Differential Geometry · Mathematics 2020-11-25 Uwe Semmelmann , Changliang Wang , M. Y. -K. Wang

We construct a 2-parameter family of new triaxial $SU(2)$-invariant complete negative Einstein metrics on the complex line bundle $\mathcal{O}(-4)$ over $\mathbb{C}P^1$. The metrics are conformally compact and neither K\"ahler nor…

Differential Geometry · Mathematics 2026-05-01 Qiu Shi Wang

We initiate a systematic study of the deformation theory of the second Einstein metric $g_{1/\sqrt{5}}$ respectively the proper nearly $G_2$ structure $\varphi_{1/\sqrt{5}}$ of a $3$-Sasaki manifold $(M^7,g)$. We show that infinitesimal…

Differential Geometry · Mathematics 2024-07-25 Paul-Andi Nagy , Uwe Semmelmann

Drawing on results of Derdzi\'nski's from the 80's, we classify conformally K\"ahler, $U(2)$-invariant, Einstein metrics on the total space of $\mathcal{O}(-m)$, for all $m \in \mathbb{N}$. This yields infinitely many $1$-parameter families…

Differential Geometry · Mathematics 2024-04-08 Gonçalo Oliveira , Rosa Sena-Dias

The classification of compact homogeneous spaces of the form $M=G/K$, where $G$ is a non-simple Lie group, such that the standard metric is Einstein is still open. The only known examples are $4$ infinite families and $3$ isolated spaces…

Differential Geometry · Mathematics 2023-11-28 Valeria Gutiérrez , Jorge Lauret

We determine purely algebraic equations to identify \textit{SLags} generated by invariant distributions in a class of non-K\"ahler Calabi-Yau manifolds. We determine SLag distributions, determine which leaves integrate to compact…

Differential Geometry · Mathematics 2026-05-05 Tristan C. Collins , Francesca Lusetti , Adriano Tomassini

We show that all compact quasi-Einstein metrics of constant scalar curvature in dimension three are locally homogeneous. We accomplish this by using the equivalence of constant scalar curvature quasi-Einstein metrics $(M,g,X)$ and…

Differential Geometry · Mathematics 2025-12-24 Eric Cochran

It has been known that there exist exactly three left-invariant Lorentzian metrics up to scaling and automorphisms on the three dimensional Heisenberg group. In this paper, we classify left-invariant Lorentzian metrics on the direct product…

Differential Geometry · Mathematics 2020-11-19 Yuji Kondo , Hiroshi Tamaru

We establish an equivalence between conformally Einstein--Maxwell Kahler 4-manifolds (recently studied in many works) and extremal Kahler 4-manifolds (in the sense of Calabi) with nowhere vanishing scalar curvature. The corresponding pairs…

Differential Geometry · Mathematics 2019-01-07 Vestislav Apostolov , David M. J. Calderbank

We investigate the existence of strong K\"ahler with torsion metrics along deformations of the Iwasawa manifold and of the holomorphically parallelizable Nakamura manifold. We also show that the class of deformations of the holomorphically…

Differential Geometry · Mathematics 2026-05-06 Ettore Lo Giudice , Lapo Rubini , Adriano Tomassini

We study left-invariant pseudo-Riemannian metrics on Lie groups using the bracket flow of the corresponding Lie algebra. We focus on metrics where the Lie algebra is in the null cone of the $G=O(p,q)$-action; i.e., Lie algebras $\mu$ where…

Differential Geometry · Mathematics 2024-11-07 Sigbjorn Hervik

We study 4-dimensional Poincar\'e-Einstein manifolds whose conformal class contains a K\"ahler metric. Such Einstein metrics are non-K\"ahler and admit a Killing field extending to the conformal infinity, and the Einstein equation reduces…

Differential Geometry · Mathematics 2025-10-07 Mingyang Li , Hongyi Liu

A conformal Lie group is a conformal manifold $(M,c)$ such that $M$ has a Lie group structure and $c$ is the conformal structure defined by a left-invariant metric $g$ on $M$. We study Weyl-Einstein structures on conformal solvable Lie…

Differential Geometry · Mathematics 2023-05-02 Viviana del Barco , Andrei Moroianu , Arthur Schichl