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Related papers: Einstein-Weyl structures on lightike hypersurfaces

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In this article we give general neccessary and sufficient conditions to ensure that a pseudo-Riemannian manifold is conformal to an Einstein space. These conditions are algorithmic in \emph{the metric tensor} whenever the Weyl endomorphism…

Differential Geometry · Mathematics 2026-01-27 Alfonso García-Parrado , Jónatan Herrera , Miguel Vadillo

In this article we review recent work on van der Waals (vdW) systems in which at least one of the components has strong spin-orbit coupling. We focus on a selection of vdW heterostructures to exemplify the type of interesting electronic…

Mesoscale and Nanoscale Physics · Physics 2020-06-04 Enrico Rossi , Christopher Triola

An almost Einstein manifold satisfies equations which are a slight weakening of the Einstein equations; Einstein metrics, Poincare-Einstein metrics, and compactifications of certain Ricci-flat asymptotically locally Euclidean structures are…

Differential Geometry · Mathematics 2008-03-26 A. Rod Gover

Weak almost contact manifolds, i.e., the linear complex structure on the contact distribution is approximated by a nonsingular skew-symmetric tensor, defined by the author and R. Wolak (2022), allowed a new look at the theory of contact…

Differential Geometry · Mathematics 2024-05-03 Vladimir Rovenski

We classify hypersurfaces of the Minkowski space $\L^{n+1}$ that carry a totally geodesic foliation with complete leaves of codimension one. We prove that such a hypersurface is ruled, or a partial tube over a curve or contains a two or…

Differential Geometry · Mathematics 2018-10-16 S. M. B. Kashani , M. J. Vanaei , S. M. Yaghoobi

In this article, we consider the almost Hermitian structure on $TM$ induced by a pair of a metric and an affine connection on $M$. We find the conditions under which $TM$ admits almost K\"ahler structures, K\"ahler structures and Einstein…

Differential Geometry · Mathematics 2025-03-24 Hiroyasu Satoh

Explicit representations of complex structures on closed manifolds are valuable, but relatively rare in the literature. Using isoparametric theory, we construct complex structures on isoparametric hypersurfaces with $g=4, m=1$ in the unit…

Differential Geometry · Mathematics 2025-02-14 Chao Qian , Zizhou Tang , Wenjiao Yan

We study conformal structure and topology of leaves of singular foliations by Riemann surfaces.

Complex Variables · Mathematics 2016-12-02 Nessim Sibony , Erlend Fornæss Wold

We consider closed orientable hypersurfaces in a wide class of warped product manifolds, which include space forms, deSitter-Schwarzschild and Reissner-Nordstr\"{o}m manifolds. By using a new integral formula or Brendle's Heintze-Karcher…

Differential Geometry · Mathematics 2019-02-14 Shanze Gao , Hui Ma

Weyl semimetals are topological materials whose electron quasiparticles obey the Weyl equation. They possess many unusual properties that may lead to new applications. This is a tutorial review of the optical properties and applications of…

Optics · Physics 2024-08-13 Cheng Guo , Viktar S. Asadchy , Bo Zhao , Shanhui Fan

We exploit the correspondence between the three-dimensional Lorentzian Einstein-Weyl geometries of the hyper-CR type, and the Veronese webs to show that the former structures are locally given in terms of solutions to the dispersionless…

Differential Geometry · Mathematics 2019-02-20 Maciej Dunajski , Wojciech Krynski

The paper focuses on the conformal Lorentz geometry of quasi-umbilical timelike surfaces in the $(1+2)$-Einstein universe, the conformal compactification of Minkowski 3-space realized as the space of oriented null lines through the origin…

Differential Geometry · Mathematics 2025-09-29 Emilio Musso , Lorenzo Nicolodi , Mason Pember

We find explicitly all bi-umbilical foliated semi-symmetric hypersurfaces in the four-dimensional Euclidean space.

Differential Geometry · Mathematics 2010-11-23 N. Kutev , V. Milousheva

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 work in both the complex and in the para-complex categories and examine (para)-K\"ahler Weyl structures in both the geometric and in the algebraic settings. The higher dimensional setting is quite restrictive. We show that any…

Differential Geometry · Mathematics 2012-04-04 P. Gilkey , S. Nikcevic

We develop the properties of Weyl geometry, beginning with a review of the conformal properties of Riemannian spacetimes. Decomposition of the Riemann curvature into trace and traceless parts allows an easy proof that the Weyl curvature…

General Relativity and Quantum Cosmology · Physics 2018-06-19 James T. Wheeler

The discovery of Weyl semimetals represents a significant advance in topological band theory. They paradigmatically enlarged the classification of topological materials to gapless systems while simultaneously providing experimental evidence…

Mesoscale and Nanoscale Physics · Physics 2018-02-14 P. Rüßmann , A. P. Weber , F. Glott , N. Xu , M. Fanciulli , S. Muff , A. Magrez , P. Bugnon , H. Berger , M. Bode , J. H. Dil , S. Blügel , P. Mavropoulos , P. Sessi

In this paper, we construct complex metric structures on complex hypersurfaces in hyperkahler manifolds. This construction is that in contact geometry.

Differential Geometry · Mathematics 2015-11-04 Mitsuhiro Imada

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

Some well-known Lorentzian concepts are transferred into the more general setting of cone structures, which provide both the causality of the spacetime and the notion of cone geodesics without making use of any metric. Lightlike…

Differential Geometry · Mathematics 2023-09-20 Miguel Ángel Javaloyes , Enrique Pendás-Recondo