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In a previous paper, the authors together with L. Vrancken initiated the study of $3$-dimensional CR submanifolds of the nearly K\" ahler homogeneous $\mathbb S^3\times \mathbb S^3$. As is shown by Butruille this is one of only four…

Differential Geometry · Mathematics 2019-11-15 Miroslava Anti\' c , Nataša Djurdjevi\' c , Marilena Moruz

Modelled on a real hypersurface in a quaternionic manifold, we introduce a quaternionic analogue of CR structure, called quaternionic CR structure. We define the strong pseudoconvexity of this structure as well as the notion of quaternionic…

Differential Geometry · Mathematics 2013-02-18 Hiroyuki Kamada , Shin Nayatani

This short paper gives a constraint on Chern classes of closed strictly pseudoconvex CR manifolds (or equivalently, closed holomorphically fillable contact manifolds) of dimension at least five. We also see that our result is ''optimal''…

Complex Variables · Mathematics 2020-01-22 Yuya Takeuchi

We study manifolds endowed with an (almost) even Clifford (hermitian) structure and admitting a large automorphism group. We classify them when they are simply connected and the dimension of the automorphism group is maximal, and also prove…

Differential Geometry · Mathematics 2016-06-07 Gerardo Arizmendi , Rafael Herrera , Noemi Santana

In this work, we prove that every complex contact structure gives rise to a distinguished type of almost contact metric 3-structure. As an application of our main result, we provide several new examples of manifolds which admit taut contact…

Differential Geometry · Mathematics 2020-09-24 Eder M. Correa

In the paper we develop a framework for the alternative way of the study of a local geometry of almost cosymplectic manifolds with Kahlerian leaves. The main idea is to apply the concept of a geometry and analysis of CR manifolds. Locally…

Differential Geometry · Mathematics 2012-10-08 Piotr Dacko

In this paper we study the topology of pseudo convex CR manifolds whose Reeb flow preserves the Levi metric.

Differential Geometry · Mathematics 2007-05-23 Aristide Tsemo

We consider locally homogeneous $CR$ manifolds and show that, under a condition only depending on their underlying contact structure, their $CR$ automorphisms form a finite dimensional Lie group.

Differential Geometry · Mathematics 2017-06-13 Stefano Marini , Costantino Medori , Mauro Nacinovich , Andrea Spiro

We study $\mathcal D$-homothetic deformations of almost $\alpha$-Kenmotsu structures. We characterize almost contact metric manifolds which are $CR$-integrable almost $\alpha$-Kenmotsu manifolds, through the existence of a canonical linear…

Differential Geometry · Mathematics 2010-06-25 Giulia Dileo

In this paper, we study a general almost Schur Lemma on pseudo-Hermitian (2n+1)-manifolds $(M,J,\theta)$ for $n\geq2$. When the equality of almost Schur inequality holds, we derive the contact form $\theta$ is pseudo-Einstein and the…

Differential Geometry · Mathematics 2014-05-14 Jui-Tang Chen , Nguyen Thac Dung , Chin-Tung Wu

For a smooth strictly pseudoconvex hypersurface in a complex manifold, we give a necessary and sufficient condition for being CR-diffeomorphic to a real-analytic CR manifold. Our condition amounts to a holomorphic extension property for the…

Complex Variables · Mathematics 2019-06-25 Ilya Kossovskiy , Dmitri Zaitsev

We consider smooth deformations of the $CR$ structure of a smooth $2$-pseudoconcave compact $CR$ submanifold $\textsf{M}$ of a reduced complex analytic variety $\textsf{X}$ outside the intersection $D\,{\cap}\,\textsf{M}$ with the support…

Complex Variables · Mathematics 2022-04-21 Judith Brinkschulte , C. Denson Hill , Mauro Nacinovich

This paper is a study of almost contact statistical manifolds. Especially this study is focused on almost cosymplectic statistical manifolds. We obtained basic properties of such manifolds. It is proved a characterization theorem and a…

Differential Geometry · Mathematics 2018-01-31 Aziz Yazla , İrem Küpeli Erken , Cengizhan Murathan

We classify the germs of $\mathcal{C}^\infty$ CR manifolds that admit a smooth CR contraction. We show that such a CR manifold is embedded into $\CC^n$ as a real hypersurface defined by a polynomial defining function consisting of monomials…

Complex Variables · Mathematics 2011-02-19 Kang-Tae Kim , Jean-Christophe Yoccoz

For almost contact metric or almost paracontact metric manifolds there is natural notion of $\eta$-normality. Manifold is called $\eta$-normal if is normal along kernel distribution of characteristic form. In the paper it is proved that…

Differential Geometry · Mathematics 2020-11-09 Piotr Dacko

We consider 6-dimensional strict nearly Kaehler manifolds acted on by a compact, cohomogeneity one automorphism group G. We classify the compact manifolds of this class up to G-diffeomorphisms. We also prove that the manifold has constant…

Differential Geometry · Mathematics 2015-05-13 Fabio Podesta' , Andrea Spiro

We study the stable embedding problem for a CR family of 3-dimensional strongly pseudoconvex CR manifolds with each fiber bounding a stein manifold.

Complex Variables · Mathematics 2019-02-21 Xiaoshan Li , Guicong Su

We obtain a Bochner type formula and an estimate from below on the spectrum of the sublaplacian of a compact strictly pseudoconvex CR manifold.

Differential Geometry · Mathematics 2007-05-23 Elisabetta Barletta

The CR Yamabe constant is an invariant of a compact strongly pseudoconvex CR manifold and plays an important role in CR geometry. We show some integral formulae of the CR Yamabe constant. We also construct an infinite-dimensional family of…

Differential Geometry · Mathematics 2025-04-09 Chanyoung Sung , Yuya Takeuchi

In this paper we classify the simply connected, spherical pseudohermitian manifolds whose Webster metric is CR-symmetric.

Differential Geometry · Mathematics 2007-11-09 G. Dileo , A. Lotta