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Related papers: K-Semistability for irregular Sasakian manifolds

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In this paper we establish some inequalities concerning the $k$-Ricci curvature of a slant submanifold in a quaternionic space form. We also obtain obstructions to the existence of quaternionic slant immersions in quaternionic space forms…

Differential Geometry · Mathematics 2013-02-13 Gabriel Eduard Vilcu

Based on uniform CR Sobolev inequality and Moser iteration, this paper investigates the convergence of closed pseudo-Hermitian manifolds. In terms of the subelliptic inequality, the set of closed normalized pseudo-Einstein manifolds with…

Differential Geometry · Mathematics 2018-02-21 Shu-Cheng Chang , Yuxin Dong , Yibin Ren

We extend to metric compact mapping tori a splitting result for coK\"ahler manifolds. In particular, we prove that a compact Vaisman manifold is finitely covered by the product of a Sasakian manifold and a circle.

Differential Geometry · Mathematics 2016-03-23 Giovanni Bazzoni , Juan Carlos Marrero , John Oprea

In the breakthrough paper [V. Mu\~noz, A Smale-Barden manifold admitting K-contact but not Sasakian structure, 2024, 10.4171/JEMS/1496], it is constructed the first example of a simply connected compact 5-manifold (aka.\ Smale-Barden…

Symplectic Geometry · Mathematics 2025-03-18 Vicente Muñoz , Juan Rojo

We prove a generalization of Hsiung-Minkowski formulas for closed submanifolds in semi-Riemannian manifolds with constant curvature. As a corollary, we obtain volume and area upper bounds for k-convex hypersurfaces in terms of a weighted…

Differential Geometry · Mathematics 2014-07-17 Kwok-Kun Kwong

A positive answer is given to the existence of Sasakian structures on the tangent sphere bundle of some Riemannian manifold whose sectional curvature is not constant. Among other results, it is proved that the tangent sphere bundle Tr(G/K),…

Differential Geometry · Mathematics 2021-05-27 J. C. González-Dávila

We study the K-stability of a polarised variety with non-reductive automorphism group. We associate a canonical filtration of the co-ordinate ring to each variety of this kind, which destabilises the variety in several examples which we…

Algebraic Geometry · Mathematics 2016-08-15 Giulio Codogni , Ruadhaí Dervan

In this paper the notion of quasi-isometry between two Riemannian manifolds has been introduced. This idea is also imposed to study quasi-isometry between two almost contact metric manifolds. Moving further, some curvature properties of two…

Differential Geometry · Mathematics 2025-11-03 Arindam Bhattacharyya , Dipen Ganguly , Paritosh Ghosh , Sumanjit Sarkar

We show that a polarized affine variety admits a Ricci flat K\"ahler cone metric, if and only if it is K-stable. This generalizes Chen-Donaldson-Sun's solution of the Yau-Tian-Donaldson conjecture to K\"ahler cones, or equivalently,…

Differential Geometry · Mathematics 2019-06-05 Tristan C. Collins , Gábor Székelyhidi

Open Calabi-Yau manifolds and log Calabi-Yau varieties have been broadly studied over decades. Regarding them as "semistable" objects, we propose to consider their good proper subclass, which we regard as certain poly-stable ones, morally…

Algebraic Geometry · Mathematics 2020-09-30 Yuji Odaka

We use Gromov's K--area to define a generalized homology theory on compact smooth manifolds. In fact, this theory collects obstructions to the enlargeability of the manifold and its nontrivial submanifolds. Moreover, using the K--area…

Differential Geometry · Mathematics 2010-08-03 Mario Listing

We introduce the notion of K-correspondence, and show that many Calabi-Yau varieties carry a lot of self-K-isocorrespondences, which furthermore satisfy the property of multiplying the canonical volume form by a constant of modulus…

Algebraic Geometry · Mathematics 2007-05-23 Claire Voisin

In this paper we study some splitting properties on complete noncompact manifolds with smooth measures when $\infty$-dimensional Bakry-\'Emery Ricci curvature is bounded from below by some negative constant and spectrum of the weighted…

Differential Geometry · Mathematics 2011-12-30 Jia-Yong Wu

We study the Lie algebra of infinitesimal isometries on compact Sasakian and K--contact manifolds. On a Sasakian manifold which is not a space form or 3--Sasakian, every Killing vector field is an infinitesimal automorphism of the Sasakian…

Differential Geometry · Mathematics 2019-01-08 Florin Belgun , Andrei Moroianu , Uwe Semmelmann

In this note we extend a recent result of S. Brendle [3] to Riemannian manifolds with densities and nonnegative Bakry-\'Emery Ricci curvature.

Differential Geometry · Mathematics 2021-03-16 Florian Johne

This paper is devoted to the first systematic investigation of manifolds that are Einstein for a connection with skew symmetric torsion. We derive the Einstein equation from a variational principle and prove that, for parallel torsion, any…

Differential Geometry · Mathematics 2022-10-07 Ilka Agricola , Ana Cristina Ferreira

We investigate the problem of approximating a regular Sasakian structure by CR immersions in a standard sphere. Namely, we show that this is always possible for compact Sasakian manifolds. Moreover, we prove an approximation result for…

Differential Geometry · Mathematics 2024-02-21 Giovanni Placini

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

Let M be a compact Sasakian manifold. We show that M admits a CR-embedding into a Sasakian manifold diffeomorphic to a sphere, and this embedding is compatible with the respective Reeb fields. We argue that a stronger embedding theorem…

Differential Geometry · Mathematics 2007-10-25 Liviu Ornea , Misha Verbitsky

In this paper we study K-polystability of arbitrary (possibly non-projective) compact K\"ahler manifolds admitting holomorphic vector fields. As a main result, we show that existence of a constant scalar curvature K\"ahler (cscK) metric…

Differential Geometry · Mathematics 2017-12-19 Zakarias Sjöström Dyrefelt