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In this paper we deal with two classes of mixed metric 3-structures, namely the mixed 3-Sasakian structures and the mixed metric 3-contact structures. Firstly we study some properties of the curvature of mixed 3-Sasakian structures, proving…

Differential Geometry · Mathematics 2011-12-06 Angelo V. Caldarella , Anna Maria Pastore

In this note, we construct new examples of Lorentzian Sasaki-Einstein (LSE) metrics on Smale manifolds $M.$ It has already been established in \cite{Gmz2} that such metrics exist on the so-called torsion free Smale manifolds, i.e. the…

Differential Geometry · Mathematics 2013-02-15 Ralph R. Gomez

We prove that along with the Einstein flow, any small perturbations of an $n(n \geq 4)$-dimensional, non-compact negative Einstein space with some "non-positive Weyl tensor" lead to a unique and global solution, and the solution will be…

Differential Geometry · Mathematics 2024-01-05 Jinhua Wang

In this article, we study Einstein-Weyl structures on almost cosymplectic manifolds. First we prove that an almost cosymplectic $(\kappa,\mu)$-manifold is Einstein or cosymplectic if it admits a closed Einstein-Weyl structure or two…

Differential Geometry · Mathematics 2018-11-26 Xiaomin Chen

We classify Einstein metrics on $\mathbb{R}^4$ invariant under a four-dimensional group of isometries including a principal action of the Heisenberg group. The metrics are either Ricci-flat or of negative Ricci curvature. We show that all…

Differential Geometry · Mathematics 2021-07-12 Vicente Cortés , Arpan Saha

In this article, we construct non-compact complete Einstein metrics on two infinite series of manifolds. The first series of manifolds are vector bundles with $\mathbb{S}^{4m+3}$ as principal orbit and $\mathbb{HP}^{m}$ as singular orbit.…

Differential Geometry · Mathematics 2021-05-12 Hanci Chi

We study the linear stability of Einstein metrics of Riemannian submersion type. First, we derive a general instability condition for such Einstein metrics and provide some applications. Then we study instability arising from Riemannian…

Differential Geometry · Mathematics 2018-10-11 Changliang Wang , Y. K. Wang

Let $M$ be an oriented closed 4-manifold and $\cL$ be a $spin^c$ structure on $M$. In this paper we prove that under a suitable condition the Seiberg-Witten moduli space has a canonical spin structure and its spin bordism class is an…

Differential Geometry · Mathematics 2007-05-23 H. Sasahira

Various types of Lagrange and Finsler geometries and the Einstein gravity theory, and modifications, can be modelled by nonholonomic distributions on tangent bundles/ manifolds when the fundamental geometric objects are adapted to nonlinear…

Mathematical Physics · Physics 2013-07-26 Sergiu I. Vacaru

The norm of Cartan torsion plays an important role for studying of immersion theory in Finsler geometry. Indeed, Finsler manifold with unbounded Cartan torsion can not be isometrically imbedded into any Minkowski space. In this paper, we…

Differential Geometry · Mathematics 2013-02-15 A. Tayebi , H. Sadeghi , E. Peyghan

We obtain a Kaehler Einstein structure on the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained Kaehler Einstein structure cannot have constant holomorphic sectional curvature and is…

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

We prove that the isometric embedding of any metric of differentiability class C1 in E3 exists. We use simplified notation for the given metric, namely geodesic parameters, and level parameters for the embedded surface in E3. Central to our…

Differential Geometry · Mathematics 2022-10-07 Edgar Kann

We continue our study of the mixed Einstein-Hilbert action as a functional of a pseudo-Riemannian metric and a linear connection. Its geometrical part is the total mixed scalar curvature on a smooth manifold endowed with a distribution or a…

Differential Geometry · Mathematics 2020-07-27 Vladimir Rovenski , Tomasz Zawadzki

We study topological median algebra structures on Euclidean spaces and, more generally, ER homology manifolds. We show that all such median structures have a local CAT(0) cubulation structure. We also show that topological median algebra…

Geometric Topology · Mathematics 2025-12-11 Mladen Bestvina , Kenneth Bromberg , Michah Sageev

Einstein-Weyl geometry is a triple (D,g,w), where D is a symmetric connection, [g] is a conformal structure and w is a covector such that: (i) connection D preserves the conformal class [g], that is, Dg=wg; (ii) trace-free part of the…

Exactly Solvable and Integrable Systems · Physics 2022-06-29 Sobhi Berjawi , Eugene Ferapontov , Boris Kruglikov , Vladimir Novikov

We treat the semiclassical Einstein equation as a quantum-classical hybrid and demonstrate the formal equivalence of its two derivation methods. This approach identifies the left-hand side of the equation as the expectation value of the…

General Relativity and Quantum Cosmology · Physics 2024-12-25 Daniel R. Terno

Given a parabolic geometry on a smooth manifold $M$, we study a natural affine bundle $A \to M$, whose smooth sections can be identified with Weyl structures for the geometry. We show that the initial parabolic geometry defines a reductive…

Differential Geometry · Mathematics 2024-10-14 Andreas Cap , Thomas Mettler

Liko and Wesson have recently introduced a new 5-dimensional induced matter solution of the Einstein equations, a negative curvature Robertson-Walker space embedded in a Riemann flat 5-dimensional manifold. We show that this solution is a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Harry I. Ringermacher , Lawrence R. Mead

Riemannian geometry in four dimensions naturally leads to an SL(3) connection that annihilates a basis for self-dual two-forms. Einstein's equations may be written in terms of an SO(3) connection, with SO(3) chosen as an appropriate…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ingemar Bengtsson

Let U be a real form of a complex semisimple Lie group, and tau, sigma, a pair of commuting involutions on U. This data corresponds to a reflective submanifold of a symmetric space, U/K. We define an associated integrable system, and…

Differential Geometry · Mathematics 2007-10-06 David Brander