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Related papers: On complex points of codimension 2 submanifolds

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This paper is concerned with the problem of constructing a smooth Levi-flat hypersurface locally or globally attached to a real codimension two submanifold in $\mathbb C^{n+1}$, or more generally in a Stein manifold, with elliptic CR…

Complex Variables · Mathematics 2024-09-16 Hanlong Fang , Xiaojun Huang , Wanke Yin , Zhengyi Zhou

This paper explores the geometry of the space of codimension-2 submanifolds. We implicitly represent these submanifolds by a class of complex-valued functions. We show that the space of all these implicit representations admits a prequantum…

Symplectic Geometry · Mathematics 2026-04-20 Albert Chern , Sadashige Ishida

A manifold is locally \emph{$k$-fold symmetric}, if for any point and any $k$-dimensional vector subspace tangent to this point there exists a local isometry such that this point is a fixed point and the differential of the isometry…

Differential Geometry · Mathematics 2018-02-05 Shaoqiang Deng , Vladimir S. Matveev

In this paper, we study deformations of coisotropic submanifolds in a locally conformal symplectic manifold. Firstly, we derive the equation that governs $C^\infty$ deformations of coisotropic submanifolds and define the corresponding…

Symplectic Geometry · Mathematics 2016-06-21 Hông Vân Lê , Yong-Geun Oh

We consider real isotropic geodesics on manifolds endowed with a pseudoconformal structure and their applications to the theory of lightlike hypersurfaces on such manifolds, the geometry of four-dimensional conformal structures of…

Differential Geometry · Mathematics 2007-05-23 Maks A. Akivis , Vladislav V. Goldberg

In this paper we study the Linial-Meshulam model of random two-dimensional complexes. We prove that a random 2-complex is homotopically one dimensional, with probability tending to one as n tends to infitnity, assuming that the probability…

Algebraic Topology · Mathematics 2010-05-20 Daniel C. Cohen , Michael Farber , Thomas Kappeler

We characterise simply-connected biquotients which potentially admit metrics of holonomy G_2. We prove that there are at most three real homotopy types of rationally elliptic such manifolds---all of them being formal. In the course of this…

Differential Geometry · Mathematics 2014-03-07 Manuel Amann

In two former papers, the authors independently proved that the space of hyperbolic cone-3-manifolds with cone angles less than 2{\pi} and fixed singular locus is locally parametrized by the cone angles. In this sequel, we investigate the…

Differential Geometry · Mathematics 2014-11-11 Grégoire Montcouquiol , Hartmut Weiß

The purpose of this article is to classify the real hypersurfaces in complex space forms of dimension 2 that are both Levi-flat and minimal. The main results are as follows: When the curvature of the complex space form is nonzero, there is…

Differential Geometry · Mathematics 2007-05-23 Robert L. Bryant

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…

Differential Geometry · Mathematics 2022-10-19 A. de Carvalho , S. Chion , M. Dajczer

The subject for investigation in this note is concerned with holomorphic Poisson structures on nilmanifolds with abelian complex structures. As a basic fact, we establish that on such manifolds, the Dolbeault cohomology with coefficients in…

Differential Geometry · Mathematics 2016-01-11 Zhuo Chen , Anna Fino , Yat-Sun Poon

We investigate the local geometry of a pair of independent contact structures on 3-manifolds under maps that independently preserve each contact structure. We discover that such maps are homotheties on the contact 1-forms and we discover…

Differential Geometry · Mathematics 2024-05-22 Taylor J. Klotz , George R. Wilkens

In this paper, a lot of examples of four-dimensional manifolds with an almost hypercomplex pseudo-Hermitian structure are constructed in several explicit ways. The received 4-manifolds are characterized by their linear invariants in the…

Differential Geometry · Mathematics 2012-05-08 Mancho Manev , Kouei Sekigawa

We describe relations between hyperbolic geometry and codimension two knots or, more exactly, between varieties of conjugacy classes of discrete faithful representations of the fundamental groups of hyperbolic n-manifolds M into…

Geometric Topology · Mathematics 2007-05-23 Boris Apanasov

We construct orbifolds with quasitoric boundary and show that they have stable almost complex structure. We show that a quasitoric orbifold is complex cobordant to finite disjoint copies of complex orbifold projective spaces. Finally some…

Algebraic Topology · Mathematics 2016-02-01 Soumen Sarkar

We obtain a complete classification of complex Kobayashi-hyperbolic manifolds of dimension $n\ge 2$, for which the dimension of the group of holomorphic automorphisms is equal to $n^2$.

Complex Variables · Mathematics 2007-05-23 A. V. Isaev

It is well known that isoperimetric regions in a smooth compact $(n+1)$-manifold are smooth, up to a closed set of codimension at most $6$. In this note, we first construct an $8$-dimensional compact smooth manifold whose unique…

Differential Geometry · Mathematics 2023-02-28 Gongping Niu

In this paper, we consider hypergraphs whose vertices are distinct points moving smoothly on a Riemannian manifold M. We take these hypergraphs as graded submanifolds of configuration spaces. We construct double complexes of differential…

Algebraic Topology · Mathematics 2025-05-14 Shiquan Ren

This is a survey paper. We explain the known constructions for two geometrically different classes of examples of compact Riemannian 7-manifolds with holonomy G2. One method uses resolutions of singularities of appropriately chosen…

Differential Geometry · Mathematics 2019-09-26 Alexei Kovalev

We provide a closed, simply connected, symplectic $6$-manifold having infinitely many codimension $2$ symplectic submanifolds. These are mutually homologous but homotopy inequivalent, and furthermore, they cannot admit complex structures.…

Symplectic Geometry · Mathematics 2025-06-17 Takahiro Oba