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Related papers: Kodaira Dimension and the Yamabe Problem, II

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The paper studies the deformation theory of a holomorphic surjective map from a normal compact complex space to a compact Kaehler manifold and describes the component of the space of holomorphic maps, generalizing results in the projective…

Algebraic Geometry · Mathematics 2007-05-23 Jun-Muk Hwang , Thomas Peternell

We consider a compact pseudo-hermitian manifold (M,\theta, J), that is a manifold equipped with a contact form \theta and CR structure J. We consider a conformal deformation of the contact form to obtain a complete, singular contact form…

Differential Geometry · Mathematics 2025-04-10 Sagun Chanillo , Paul C. Yang

The compact complex manifolds considered in this article are principal torus bundles over a torus. We consider the Kodaira Spencer map of the complete Appell Humbert family (introduced by the first author in Part I) and are able to show…

Complex Variables · Mathematics 2007-05-23 Fabrizio Catanese , Paola Frediani

We study the Yamabe invariant of manifolds obtained as connected sums along submanifolds of codimension greater than 2. In particular, given a compact smooth manifold M which does not admit metrics of positive scalar curvature, we prove…

Differential Geometry · Mathematics 2007-05-23 Jimmy Petean , Gabjin Yun

We compute the Yamabe invariants for a new infinite class of closed $4$-dimensional manifolds by using a "twisted" version of the Seiberg-Witten equations, the $\mathrm{Pin}^-(2)$-monopole equations. The same technique also provides a new…

Differential Geometry · Mathematics 2020-09-22 Masashi Ishida , Shinichiroh Matsuo , Nobuhiro Nakamura

Assume that M is a compact n-dimensional manifold and that N is obtained by surgery along a k-dimensional sphere, k\le n-3. The smooth Yamabe invariants \sigma(M) and \sigma(N) satisfy \sigma(N)\ge min (\sigma(M),\Lambda) for \Lambda>0. We…

Geometric Topology · Mathematics 2015-01-28 Bernd Ammann , Mattias Dahl , Emmanuel Humbert

We observed in our previous paper that all the complex structures on four-dimensional compact solvmanifolds, including tori, are left-invariant. In this paper we will give an example of a six-dimensional compact solvmanifold which admits a…

Complex Variables · Mathematics 2016-01-15 Keizo Hasegawa

We define an invariant for compact spin manifolds $X$ of dimension $4k$ equipped with a metric $h$ of positive Yamabe invariant on its boundary. The vanishing of this invariant is a necessary condition for the conformal class of $h$ to be…

Differential Geometry · Mathematics 2018-01-16 Matthew J. Gursky , Qing Han , Stephan Stolz

We prove that in conformal classes of metrics near the class of an Einstein metric (other than the standard round metric on a sphere) the Yamabe problem has a unique solution up to scaling. This is a local extension, in the space of…

Differential Geometry · Mathematics 2011-06-10 L. L. de Lima , P. Piccione , M. Zedda

We start by taking the analytical approach to discuss how the minimizer of Yamabe functional provides constant scalar curvature and its relationship with the Sobolev Space $W^{1,2}.$ Then, after demonstrating the importance of the sphere…

Differential Geometry · Mathematics 2024-12-09 Aoran Chen

We show that degenerate complex Monge-Ampere equations in a big cohomology class of a compact Kaehler manifold can be solved using a variational method independent of Yau's theorem. Our formulation yields in particular a natural…

Complex Variables · Mathematics 2009-07-28 R. J. Berman , S. Boucksom , V. Guedj , A. Zeriahi

In this paper, we will prove subadditivity of Kodaira dimensions for a fibration with possibly singular geometric generic fiber, under certain nefness and relative semi-ampleness conditions. As an application, for a fibration $f: X \to Y$…

Algebraic Geometry · Mathematics 2019-07-18 Lei Zhang

We follow our study of non-K\"ahler complex structures on $R^4$ that we defined in a previous paper. We prove that these complex surfaces do not admit any smooth complex compactification. Moreover, we give an explicit description of their…

Complex Variables · Mathematics 2020-08-05 Antonio J. Di Scala , Naohiko Kasuya , Daniele Zuddas

This is the second of a series of papers where we study the plurigenera, the Kodaira dimension and the Iitaka dimension on compact almost complex manifolds. By using the pseudoholomorphic pluricanonical map, we define the second version of…

Differential Geometry · Mathematics 2020-04-28 Haojie Chen , Weiyi Zhang

We prove that the Yamabe invariant of any simply connected smooth manifold of dimension n greater than four is non-negative. Equivalently that the infimum of the L^{n/2} norm of the scalar curvature, over the space of all Riemannian metrics…

Differential Geometry · Mathematics 2007-05-23 Jimmy Petean

We consider Calabi-Yau threefolds $X$ over an algebraically closed field $k$ of characteristic $p>0$ that are not liftable to characteristic $0$ or liftable ones with $p=2$. It is unknown whether Kodaira vanishing holds for these varieties.…

Algebraic Geometry · Mathematics 2017-02-15 Yukihide Takayama

Given a conformally variational scalar Riemannian invariant $I$, we identify a sufficient condition for a compact Riemannian manifold to admit finite regular coverings with many nonhomothetic conformal rescalings with $I$ constant. We also…

Differential Geometry · Mathematics 2025-10-08 João Henrique Andrade , Jeffrey S. Case , Paolo Piccione , Juncheng Wei

We show that if $(M,\omega)$ is any compact K\"ahler manifold, then the blowup of $M$ at any point furnishes a K\"ahler metric with scalar curvature globally and arbitrarily $C^0$-close to the scalar curvature of $\omega$. It follows that…

Differential Geometry · Mathematics 2026-01-28 Garrett M. Brown

In this note we consider M-theory compactified on a warped Calabi-Yau fourfold including the eight-derivative terms in the eleven-dimensional action known in the literature. We dimensionally reduce this theory on geometries with one Kahler…

High Energy Physics - Theory · Physics 2020-05-20 Thomas W. Grimm , Kilian Mayer , Matthias Weissenbacher

We study the Kodaira dimension of a real parallelizable manifold $M$, with an almost complex structure $J$ in standard form with respect to a given parallelism. For $X = (M, J)$ we give conditions under which $\operatorname{kod}(X) = 0$. We…

Differential Geometry · Mathematics 2023-07-26 Andrea Cattaneo , Antonella Nannicini , Adriano Tomassini