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Related papers: Subharmonicity of direct images and applications

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In this note, we discuss the notion of symmetric self-duality of shaded planar algebras, which allows us to lift shadings on subfactor planar algebras to obtain Z/2Z-graded unitary fusion categories. This finishes the proof that there are…

Operator Algebras · Mathematics 2017-09-18 Zhengwei Liu , Scott Morrison , David Penneys

Let A be an elliptic curve, and let $V_A$ be the Serre vector bundle on A. A famous example of Demailly-Peternell-Schneider shows that the tautological class of $V_A$ contains a unique closed positive current. In this survey we start by…

Algebraic Geometry · Mathematics 2023-02-27 Junyan Cao , Andreas Höring

Given a perversity function in the sense of intersection homology theory, the method of intersection spaces assigns to certain oriented stratified spaces cell complexes whose ordinary reduced homology with real coefficients satisfies…

Algebraic Topology · Mathematics 2019-10-23 Markus Banagl , Eugenie Hunsicker

In this paper, we consider a proper K\"ahler fibration $f \colon X \to Y$ and a singular Hermitian line bundle $(L, h)$ on $X$ with semi-positive curvature. We prove that the direct image sheaf $f_{*}(\mathcal{O}_{X}(K_{X/Y}+L) \otimes…

Algebraic Geometry · Mathematics 2024-08-19 Takahiro Inayama , Shin-ichi Matsumura , Yuta Watanabe

Given an effectively parameterized family $f:X\to S$ of canonically polarized manifolds, the K\"ahler-Einstein metrics on the fibers induce a hermitian metric on the relative canonical bundle $K_{X/S}$. We use a global elliptic equation to…

Complex Variables · Mathematics 2010-05-20 Georg Schumacher

The purpose of this paper is to establish injectivity theorems for higher direct image sheaves of canonical bundles twisted by pseudo-effective line bundles and multiplier ideal sheaves. As applications, we generalize Koll'ar's torsion…

Complex Variables · Mathematics 2018-01-29 Shin-ichi Matsumura

We consider spaces for which there is a notion of harmonicity for complex valued functions defined on them. For instance, this is the case of Riemannian manifolds on one hand, and (metric) graphs on the other hand. We observe that it is…

Metric Geometry · Mathematics 2016-08-16 Sylvain Barré , Abdelghani Zeghib

In this paper, we study the descent of positivity of the canonical bundle along fiber spaces. As a consequence, we prove a conjecture of Schnell, establishing the equivalence between the Non-vanishing Conjecture and its generalized version…

Algebraic Geometry · Mathematics 2025-12-23 Yongpan Zou

We assign a relational structure to any finite algebra in a canonical way, using solution sets of equations, and we prove that this relational structure is polymorphism-homogeneous if and only if the algebra itself is…

Logic · Mathematics 2024-02-14 Endre Tóth , Tamás Waldhauser

We present enumerative results for holomorphic foliations by curves on $\mathbb{P}^n$, $n\geq 3$, with singularities of positive dimension. Some of the results presented improve previous ones due to Corr\^ea--Fern\'andez-P\'erez--Nonato…

Algebraic Geometry · Mathematics 2017-11-09 Arturo Fernández-Pérez , Gilcione Nonato Costa

Building on Fujita-Griffiths method of computing metrics on Hodge bundles, we show that the direct image of an adjoint semi-ample line bundle by a projective submersion has a continuous metric with Griffiths semi-positive curvature. This…

Algebraic Geometry · Mathematics 2018-05-24 Christophe Mourougane , Shigeharu Takayama

By applying the positivity theorem of direct images and a pluricanonical version of the structure theorem on the cohomology jumping loci \`a la Green-Lazarsfeld-Simpson, we show that the klt K\"ahler version of the Iitaka conjecture…

Algebraic Geometry · Mathematics 2019-07-17 Juanyong Wang

The goal of this contribution is to investigate L${}^2$ extension properties for holomorphic sections of vector bundles satisfying weak semi-positivity properties. Using techniques borrowed from recent proofs of the Ohsawa-Takegoshi…

Complex Variables · Mathematics 2015-10-20 Jean-Pierre Demailly

We introduce and study birational invariants for foliations on projective surfaces built from the adjoint linear series of positive powers of the canonical bundle of the foliation. We apply the results in order to investigate the effective…

Algebraic Geometry · Mathematics 2019-06-13 Jorge Vitorio Pereira , Roberto Svaldi

Given a vector bundle $E$ on an irreducible projective variety $X$ we give a necessary and sufficient criterion for $E$ to be a direct image of a line bundle under an \'etale morphism. The criterion in question is the existence of a Cartan…

Algebraic Geometry · Mathematics 2017-05-24 Robert Auffarth , Indranil Biswas

We prove that the higher direct images of the dualizing sheaf of a Lagrangian fibration between smooth projective manifolds are isomorphic to the cotangent bundles of base space. As a corollary, we obtain that every Hodge number of the base…

Algebraic Geometry · Mathematics 2016-09-07 Daisuke Matsushita

Let $k$ be an infinite finitely generated field of characteristic $p>0$. Fix a separated scheme $X$ smooth, geometrically connected, and of finite type over $k$ and a smooth proper morphism $f:Y\rightarrow X$. The main result of this paper…

Algebraic Geometry · Mathematics 2025-10-31 Emiliano Ambrosi

We calculate curvature tensors of metrics on the total spaces of holomorphic fibrations. Our main tool is a theory of Chern connections and curvature forms for possibly degenerate Hermitian forms on holomorphic vector bundles. We prove a…

Algebraic Geometry · Mathematics 2022-10-06 Gunnar Þór Magnússon

In the first part of the paper, we study a Fujita-type conjecture by Popa and Schnell, and give an effective bound on the generic global generation of the direct image of the twisted pluricanonical bundle. We also point out the relation…

Algebraic Geometry · Mathematics 2017-10-24 Ya Deng

We establish rigidity results for holomorphic mappings and plurisubharmonic functions in complex geometry. First, under mild conditions, we show that the gradient of a $\operatorname{U}(1)$-invariant strictly plurisubharmonic function in…

Complex Variables · Mathematics 2026-04-30 Hanwen Liu
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