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A metric projective structure is a manifold equipped with the unparametrised geodesics of some pseudo-Riemannian metric. We make acomprehensive treatment of such structures in the case that there is a projective Weyl curvature nullity…

微分几何 · 数学 2017-11-28 A. Rod Gover , Vladimir S. Matveev

We show that conformally compact, globally hyperbolic, Lorentzian Einstein-Weyl 3-manifolds are in natural one-to-one correspondence with orientation-reversing diffeomorphisms of the 2-sphere. The proof hinges on a holomorphic-disk analog…

微分几何 · 数学 2008-07-25 Claude LeBrun , L. J. Mason

Building on previous results, we complete the classification of compact oriented Einstein 4-manifolds with det (W^+) > 0. There are, up to diffeomorphism, exactly 15 manifolds that carry such metrics, and, on each of these manifolds, such…

微分几何 · 数学 2020-07-03 Claude LeBrun

We consider conformally invariant form of the actions in Einstein, Weyl, Einstein-Cartan and Einstein-Cartan-Weyl space in general dimensions($>2$) and investigate the relations among them. In Weyl space, the observational consistency…

广义相对论与量子宇宙学 · 物理学 2010-11-23 Tae Yoon Moon , Joohan Lee , Phillial Oh

We study Weyl conformal geometry as a general gauge theory of the Weyl group (of Poincar\'e and dilatations symmetries) in a manifestly Weyl gauge covariant formalism in which this geometry is automatically metric and physically relevant.…

高能物理 - 理论 · 物理学 2025-03-31 C. Condeescu , D. M. Ghilencea , A. Micu

We describe a method to generate scalar-tensor theories with Weyl symmetry, starting from arbitrary purely metric higher derivative gravity theories. The method consists in the definition of a conformally-invariant metric $\hat{g}_{\mu…

高能物理 - 理论 · 物理学 2023-12-12 Giorgos Anastasiou , Ignacio J. Araya , Avik Chakraborty

A discussion is given of the conformal Einstein field equations coupled with matter whose energy-momentum tensor is trace-free. These resulting equations are expressed in terms of a generic Weyl connection. The article shows how in the…

广义相对论与量子宇宙学 · 物理学 2015-05-27 Christian Lübbe , Juan Antonio Valiente Kroon

Let $f\colon M^{2n}\to\mathbb{R}^{2n+\ell}$, $n \geq 5$, denote a conformal immersion into Euclidean space with codimension $\ell$ of a Kaehler manifold of complex dimension $n$ and free of flat points. For codimensions $\ell=1,2$ we show…

微分几何 · 数学 2022-10-19 A. de Carvalho , S. Chion , M. Dajczer

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…

微分几何 · 数学 2019-11-25 Andreas Arvanitoyeorgos , Ioannis Chrysikos , Yusuke Sakane

Any $6$-dimensional strict nearly K\"ahler manifold is Einstein with positive scalar curvature. We compute the coindex of the metric with respect to the Einstein-Hilbert functional on each of the compact homogeneous examples. Moreover, we…

微分几何 · 数学 2022-08-25 Paul Schwahn

Analysis of the geodesics in the space of signature $(1,3)$ that splits in two-dimensional distributions resulting from the Weyl tensor eignespaces - hyperbolic and elliptic ones - described in [V. Lychagin, V. Yumaguzhin,…

数学物理 · 物理学 2019-05-28 Radosław A. Kycia , Maria Ułan

Minimal surfaces and Einstein manifolds are among the most natural structures in differential geometry. Whilst minimal surfaces are well understood, Einstein manifolds remain far less so. This exposition synthesises together a set of…

微分几何 · 数学 2025-08-19 Mia Beard

We consider holography of two pp-wave metrics in conformal gravity, their one point functions, and asymptotic symmetries. One of the metrics is a generalization of the standard pp-waves in Einstein gravity to conformal gravity. The…

高能物理 - 理论 · 物理学 2021-04-07 A. Bhatnagar , I. Lovrekovic

We consider a homogeneous fibration $G/L \to G/K$, with symmetric fiber and base, where $G$ is a compact connected semisimple Lie group and $L$ has maximal rank in $G$. We suppose the base space $G/K$ is isotropy irreducible and the fiber…

微分几何 · 数学 2009-07-06 Fatima Araujo

This is a survey on quaternion Hermitian Weyl (locally conformally quaternion K\"ahler) and hyperhermitian Weyl (locally conformally hyperk\"ahler) manifolds. These geometries appear by requesting the compatibility of some quaternion…

微分几何 · 数学 2007-05-23 Liviu Ornea

Using a recently developed generalized Weyl formalism, we construct an asymptotically flat, static vacuum Einstein solution that describes a superposition of multiple five-dimensional Schwarzschild black holes. The spacetime exhibits a…

高能物理 - 理论 · 物理学 2009-11-10 H. S. Tan , Edward Teo

We obtain a volume growth and curvature decay result for various classes of complete, noncompact Riemannian metrics in dimension 4; in particular our method applies to anti-self-dual or Kahler metrics with zero scalar curvature, and metrics…

微分几何 · 数学 2009-11-10 Gang Tian , Jeff Viaclovsky

We construct indefinite Einstein solvmanifolds that are standard, but not of pseudo-Iwasawa type. Thus, the underlying Lie algebras take the form $\mathfrak{g}\rtimes_D\mathbb{R}$, where $\mathfrak{g}$ is a nilpotent Lie algebra and $D$ is…

微分几何 · 数学 2024-06-27 Diego Conti , Federico A. Rossi , Romeo Segnan Dalmasso

It is known that the almost-Kaehler anti-self-dual metrics on a given 4-manifold sweep out an open subset in the moduli space of anti-self-dual metrics. However, we show here by example that this subset is not generally closed, and so need…

微分几何 · 数学 2018-01-22 Christopher J. Bishop , Claude LeBrun

We investigate the geometry of a twisting non-shearing congruence of null geodesics on a conformal manifold of even dimension greater than four and Lorentzian signature. We give a necessary and sufficient condition on the Weyl tensor for…

微分几何 · 数学 2021-09-01 Arman Taghavi-Chabert