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This is the very first paper to focus on the CR analogue of Yau's uniformization conjecture in a complete noncompact pseudohermitian $(2n+1)$-manifold of vanishing torsion (i.e. Sasakian manifold) which is an odd dimensional counterpart of…

Differential Geometry · Mathematics 2018-04-18 Shu-Cheng Chang , Yingbo Han , Chien Lin

The object of this paper is to study the invariant submanifolds of Sasakian generalized-Sasakian-space-form. Here, we obtain some equivalent conditions for an invariant submanifold of a Sasakian generalized-Sasakian-space-forms to be…

Differential Geometry · Mathematics 2022-12-12 D. G. Prakasha , P. Veeresha , Inan Unal , Shyamal Kumar Hui

We find a family of five dimensional completely solvable compact manifolds that constitute the first examples of $K$-contact manifolds which satisfy the Hard Lefschetz Theorem and have a model of Tievsky type just as Sasakian manifolds but…

Differential Geometry · Mathematics 2016-10-07 Beniamino Cappelletti-Montano , Antonio De Nicola , Juan Carlos Marrero , Ivan Yudin

We introduce the classes of holomorphic $p$-contact manifolds and holomorphic $s$-symplectic manifolds that generalise the classical holomorphic contact and holomorphic symplectic structures. After observing their basic properties and…

Differential Geometry · Mathematics 2025-11-18 Hisashi Kasuya , Dan Popovici , Luis Ugarte

We provide a new, self-contained and more conceptual proof of the result that an almost contact metric manifold of dimension greater than 5 is Sasakian if and only if it is nearly Sasakian.

Differential Geometry · Mathematics 2019-09-13 Beniamino Cappelletti-Montano , Antonio De Nicola , Giulia Dileo , Ivan Yudin

Under a pulled-back approach given in [1] and firstly presented in [2], we introduce, in this paper, the concepts of almost contact and normal almost contact Finsler structures on the pulled-back bundle. Properties of structures partly…

Differential Geometry · Mathematics 2016-06-22 Fortuné Massamba , Salomon Joseph Mbatakou

We introduce the notion of paraquaternionic contact structures (pqc structures), which turns out to be a generalization of the para 3-Sasakian geometry. We derive a distinguished linear connection preserving the pqc structure. Its torsion…

Differential Geometry · Mathematics 2024-05-03 Marina Tchomakova , Stefan Ivanov , Simeon Zamkovoy

We classify the normal CR structures on $S^3$ and their automorphism groups. Together with [3], this closes the classification of normal CR structures on contact 3-manifolds. We give a criterion to compare 2 normal CR structures, and we…

Differential Geometry · Mathematics 2007-05-23 Florin Alexandru Belgun

We investigate some topological properties, in particular formality, of compact Sasakian manifolds. Answering some questions raised by Boyer and Galicki, we prove that all higher (than three) Massey products on any compact Sasakian manifold…

Differential Geometry · Mathematics 2018-08-07 Indranil Biswas , Marisa Fernández , Vicente Muñoz , Aleksy Tralle

The purpose of this paper is to study the Sasakian geometry on odd dimensional sphere bundles over a smooth projective algebraic variety $N$ with the ultimate, but probably unachievable goal of understanding the existence and non-existence…

Differential Geometry · Mathematics 2021-09-29 Charles P. Boyer , Christina W. Tønnesen-Friedman

Walczak formula is a very nice tool for understanding the geometry of a Riemannian manifold equipped with two orthogonal complementary distributions. Svensson [7] has shown that this formula simplifies to a Bochner type formula when we are…

Differential Geometry · Mathematics 2007-05-23 Vasile Brinzanescu , Radu Slobodeanu

A Sasakian manifold is a Riemannian manifold whose metric cone admits a certain K\"ahler structure which behaves well under homotheties. We show that the product of two compact Sasakian manifolds admits a family of complex structures…

Differential Geometry · Mathematics 2025-06-04 Vlad Marchidanu

In all odd dimensions $\geq 5$ we produce examples of manifolds admitting pairs of Sasaki structures with different basic Hodge numbers. In dimension $5$ we prove more precise results, for example we show that on connected sums of copies of…

Differential Geometry · Mathematics 2023-01-03 D. Kotschick , G. Placini

We show that, for any given $q\geq 0$, any Sasakian structure on a closed manifold $M$ is approximated in the $C^{q}$-norm by structures induced by CR embeddings into weighted Sasakian spheres. In order to obtain this result, we also…

Differential Geometry · Mathematics 2024-08-27 Andrea Loi , Giovanni Placini

k-Contact geometry is a generalisation of contact geometry to analyse field theories. We develop an approach to k-contact geometry based on distributions that are distributionally maximally non-integrable and admit, locally, k commuting…

Differential Geometry · Mathematics 2025-02-06 Javier de Lucas , Xavier Rivas , Tomasz Sobczak

Using the Hard Lefschetz Theorem for Sasakian manifolds, we find two examples of compact K-contact nilmanifolds with no compatible Sasakian metric in dimensions five and seven, respectively

Differential Geometry · Mathematics 2014-10-24 Beniamino Cappelletti-Montano , Antonio De Nicola , Juan Carlos Marrero , Ivan Yudin

We study normal CR compact manifolds in dimension 3. For a choice of a CR Reeb vector field, we associate a Sasakian metric on them, and we classify those metrics. As a consequence, the underlying manifolds are topologically finite quotiens…

Differential Geometry · Mathematics 2007-05-23 F. A. Belgun

We characterize the Dirac structures that are parallel with respect to Gualtieri's canonical connection of a generalized Riemannian metric. On the other hand, we discuss Dirac structures that are images of generalized tangent structures.…

Differential Geometry · Mathematics 2011-05-31 Izu Vaisman

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

A contact manifold is a manifold equipped with a distribution of codimension one that satisfies a `maximal non-integrability' condition. A standard example of a contact structure is a strictly pseudoconvex CR manifold, and operators of…

Differential Geometry · Mathematics 2011-11-28 Erik van Erp