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A pseudo-Einstein contact form plays a crucial role in defining some global invariants of closed strictly pseudoconvex CR manifolds. In this paper, we prove that the existence of a pseudo-Einstein contact form is preserved under…

Differential Geometry · Mathematics 2020-01-22 Yuya Takeuchi

In this note, we mainly focus on the existence of pseudo-Einstein contact forms, an upper bound eigenvalue estimate for the CR Paneitz operator and its applications to the uniformization theorem for Sasakian space form in an embeddable…

Differential Geometry · Mathematics 2019-06-26 Shu-Cheng Chang , Ting-Jung Kuo , Chien Lin

We construct contact forms with constant $Q^\prime$-curvature on compact three-dimensional CR manifolds which admit a pseudo-Einstein contact form and satisfy some natural positivity conditions. These contact forms are obtained by…

Differential Geometry · Mathematics 2015-11-17 Jeffrey S. Case , Chin-Yu Hsiao , Paul Yang

We construct contact forms with constant $Q^\prime$-curvature on compact three-dimensional CR manifolds which admit a pseudo-Einstein contact form and satisfy some natural positivity conditions. These contact forms are obtained by…

Differential Geometry · Mathematics 2016-02-10 Jeffrey S. Case , Chin-Yu Hsiao , Paul Yang

This paper constructs a family of coordinate systems about a point on a quaternionic contact manifold, called quaternionic contact pseudohermitian normal coordinates. Once defined, conformal variations of the quaternionic contact structure…

Differential Geometry · Mathematics 2008-07-04 Christopher S. Kunkel

First we introduce a generalization of symmetric spaces to parabolic geometries. We provide construction of such parabolic geometries starting with classical symmetric spaces and we show that all regular parabolic geometries with smooth…

Differential Geometry · Mathematics 2012-07-30 Jan Gregorovič

In this study, we investigate generalized quasi-Einstein structure for normal metric contact pair manifolds. Firstly, we deal with elementary properties and examine, existence, and characterizations of generalized quasi-Einstein normal…

Differential Geometry · Mathematics 2021-02-23 İnan Ünal

One of effective ways to solve the equivalence problem and describe moduli spaces for real submanifolds in complex space is the normal form approach. In this survey, we outline some normal form constructions in CR-geometry and formulate a…

Complex Variables · Mathematics 2016-06-28 Martin Kolar , Ilya Kossovskiy , Dmitri Zaitsev

The general theory of parabolic geometries is applied to the study of the normal Cartan connections for all hyperbolic and elliptic 6-dimensional CR-manifolds of codimension two. The geometric meaning of the individual components of the…

Differential Geometry · Mathematics 2007-05-23 Gerd Schmalz , Jan Slovak

In this paper we compute the first and second variation of the normalized Einstein-Hilbert functional on CR manifolds. We characterize critical points as pseudo-Einstein structures. We then turn to the second variation on standard spheres.…

Differential Geometry · Mathematics 2023-06-14 Claudio Afeltra , Jih-Hsin Cheng , Andrea Malchiodi , Paul Yang

In previous work (arXiv:2205.12067), we defined a notion of a generalized Sasakian structure in the context of generalized contact geometry, the odd dimensional analogue of generalized complex geometry introduced by Hitchin and Gualtieri.…

Differential Geometry · Mathematics 2024-08-27 Janet Talvacchia

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 consider local geometry of sub-pseudo-Riemannian structures on contact manifolds. We construct fundamental invariants of the structures and show that the structures give rise to Einstein-Weyl geometries in dimension 3, provided that…

Differential Geometry · Mathematics 2015-03-25 Marek Grochowski , Wojciech Krynski

It is formally constructed a normal form for a class of real-formal surfaces defined near a CR Singularity.

Complex Variables · Mathematics 2021-01-28 Valentin Burcea

In this paper, we give explicit formulae of the Burns-Epstein invariant and global CR invariants via renormalized characteristic forms introduced by Marugame for Sasakian $\eta$-Einstein manifolds. As an application, we show that the latter…

Differential Geometry · Mathematics 2025-02-17 Yuya Takeuchi

We relate a recently introduced non-local geometric invariant of compact strictly pseudoconvex Cauchy-Riemann (CR) manifolds of dimension 3 to various eta-invariants in CR geometry: on the one hand a renormalized eta-invariant appearing…

Differential Geometry · Mathematics 2007-05-23 Olivier Biquard , Marc Herzlich , Michel Rumin

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

Lie contact structures generalize the classical Lie sphere geometry of oriented hyperspheres in the standard sphere. They can be equivalently described as parabolic geometries corresponding to the contact grading of orthogonal real Lie…

Differential Geometry · Mathematics 2009-01-29 Vojtech Zadnik

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

It is constructed a normal form for a class of real-smooth surfaces M\subset\mathbb{C}^{2} defined near a degenerate CR singularity.

Complex Variables · Mathematics 2026-05-26 Valentin Burcea
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