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Related papers: The Geometry of Almost Einstein (2,3,5) Distributi…

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We extend Tsuji's iterative construction of complete K\"ahler--Einstein metrics with negative scalar curvature to noncompact K\"ahler manifolds with bounded geometry, using Berndtsson's method from the compact setting. Consequently, given a…

Differential Geometry · Mathematics 2026-01-13 Quang-Tuan Dang , Tat Dat Tô

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

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…

Differential Geometry · Mathematics 2022-08-25 Paul Schwahn

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…

Differential Geometry · Mathematics 2024-06-27 Diego Conti , Federico A. Rossi , Romeo Segnan Dalmasso

A Riemannian manifold endowed with $k>2$ orthogonal complementary distributions (called here a Riemannian almost $k$-product structure) appears in such topics as multiply warped products, the webs composed of several foliations, and proper…

Differential Geometry · Mathematics 2021-01-05 Vladimir Rovenski

This paper initiates the study of the Einstein equation on homogeneous supermanifolds. First, we produce explicit curvature formulas for graded Riemannian metrics on these spaces. Next, we present a construction of homogeneous…

Mathematical Physics · Physics 2026-04-01 Yang Zhang , Mark D. Gould , Artem Pulemotov , Jorgen Rasmussen

To study asymptotic structures, we regularize Einstein's field equations by means of conformal transformations. The conformal factor is chosen so that it carries a dimensional scale that captures crucial asymptotic features. By choosing a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Niklas Rohr , Claes Uggla

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

We continue our systematic development of noncommutative and nonassociative differential geometry internal to the representation category of a quasitriangular quasi-Hopf algebra. We describe derivations, differential operators, differential…

Quantum Algebra · Mathematics 2016-05-03 Gwendolyn E. Barnes , Alexander Schenkel , Richard J. Szabo

Given a parabolic geometry, it is sometimes possible to find special metrics characterised by some invariant conditions. In conformal geometry, for example, one asks for an Einstein metric in the conformal class. Einstein metrics have the…

Differential Geometry · Mathematics 2022-06-07 Michael Eastwood , Lenka Zalabová

We study the relations between the projective and the almost conformally symplectic structures on a smooth even dimensional manifold. We describe these relations by a single almost conformally symplectic connection with totally trace--free…

Differential Geometry · Mathematics 2017-10-17 Jan Gregorovič

We show that each of the topological 4-manifolds $CP^2#k\bar{CP^2}, for $k = 6, 7$ admits a smooth structure which has an Einstein metric of scalar curvature $s > 0$, a smooth structure which has an Einstein metric with $s < 0$ and…

Differential Geometry · Mathematics 2015-05-13 Rares Rasdeaconu , Ioana Suvaina

We study the question of the integrability of Einstein deformations and relate it to the question of the desingularization of Einstein metrics. Our main application is a negative answer to the long-standing question of whether or not every…

Differential Geometry · Mathematics 2021-05-28 Tristan Ozuch

We discuss a deformation of Sasakian structure in the presence of totally skew-symmetric torsion by introducing odd dimensional manifolds whose metric cones are K\"ahler with torsion. It is shown that such a geometry inherits similar…

High Energy Physics - Theory · Physics 2015-06-05 Tsuyoshi Houri , Hiroshi Takeuchi , Yukinori Yasui

We show that if a closed manifold of dimension at least four admits a negatively curved metric that is almost Einstein in a suitable sense, then it admits a genuine Einstein metric of negative sectional curvature. Importantly, the pinching…

Differential Geometry · Mathematics 2025-12-30 Frieder Jäckel

Given a projective structure on a surface $N$, we show how to canonically construct a neutral signature Einstein metric with non-zero scalar curvature as well as a symplectic form on the total space $M$ of a certain rank $2$ affine bundle…

Differential Geometry · Mathematics 2018-11-01 Maciej Dunajski , Thomas Mettler

We construct explicit examples of quaternion-K\"ahler and hypercomplex structures on bundles over hyperK\"ahler manifolds. We study the infinitesimal symmetries of these examples and the associated Galicki-Lawson quaternion-K\"ahler moment…

Differential Geometry · Mathematics 2024-10-30 Udhav Fowdar

In Part I of the present series of papers, we adumbrate our idea of Riemannian geometry to higher order in the infinitesimals and derive expressions for the appropriate generalizations of parallel transport and the Riemannian curvature…

Differential Geometry · Mathematics 2024-06-12 William Bies

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

In his 1910 "Five Variables" paper, Cartan solved the equivalence problem for the geometry of $(2, 3, 5)$ distributions and in doing so demonstrated an intimate link between this geometry and the exceptional simple Lie groups of type…

Differential Geometry · Mathematics 2017-08-23 Travis Willse
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