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We prove an Ohsawa-Takegoshi-type extension theorem on the Berkovich closed unit disc over a complete non-Archimedean field. As an application, we establish a non-Archimedean analogue of Demailly's regularization theorem for…

Algebraic Geometry · Mathematics 2018-05-09 Matthew Stevenson

We establish a new extension result for twisted canonical forms defined on a hypersurface with simple normal crossings of a projective manifold. Some of the examples presented in the appendix are showing that the bounds we obtain for the…

Complex Variables · Mathematics 2020-02-13 Junyan Cao , Mihai Paun

Let $(X,J,\omega,g)$ be a complete $n$-dimensional K\"ahler manifold. A Theorem by Gromov \cite{G} states that the if the K\"ahler form is $d$-bounded, then the space of harmonic $L_2$ forms of degree $k$ is trivial, unless $k=\frac{n}{2}$.…

Differential Geometry · Mathematics 2017-08-22 Richard Hind , Adriano Tomassini

In this note, making use of noncommutative $l$-adic cohomology, we extend the generalized Riemann hypothesis from the realm of algebraic geometry to the broad setting of geometric noncommutative schemes in the sense of Orlov. As a first…

Algebraic Geometry · Mathematics 2021-05-21 Goncalo Tabuada

Based on a recent extension theorem for reflexive differential forms, that is, regular differential forms defined on the smooth locus of a possibly singular variety, we study the geometry and cohomology of sheaves of reflexive…

Algebraic Geometry · Mathematics 2015-04-17 Daniel Greb , Stefan Kebekus , Thomas Peternell

We obtain a general Ohsawa-Takegoshi extension theorem by using the Ross-Witt Nystr\"om correspondence picture and Berndtsson's theorem in \cite{Bern20}. In the test configuration ($\mathbb C^*$-degeneration) case, our approach gives a…

Complex Variables · Mathematics 2025-07-25 Yan He , Johannes Testorf , Xu Wang

In the present paper we study abelian extensions of connected Lie groups $G$ modeled on locally convex spaces by smooth $G$-modules $A$. We parametrize the extension classes by a suitable cohomology group $H^2_s(G,A)$ defined by locally…

Group Theory · Mathematics 2007-05-23 Karl-Hermann Neeb

The aim of this work is to generalize the ultraholomorphic extension theorems from V. Thilliez in the weight sequence setting and from the authors in the weight function setting (of Roumieu type) to a mixed framework. Such mixed results…

Complex Variables · Mathematics 2022-12-29 Javier Jiménez-Garrido , Javier Sanz , Gerhard Schindl

Employing Morse theory for the global control of monodromy and the method of analytic discs for local extension, we establish a version of the global Hartogs extension theorem in a singular setting: for every domain D of an (n-1)-complete…

Complex Variables · Mathematics 2007-05-23 Joel Merker , Egmont Porten

In $L^2$ extension theorems from a singular hypersurface in a complex manifold, important roles are played by certain measures such as the Ohsawa measure which determine when a given function can be extended. We show that the singularity of…

Complex Variables · Mathematics 2023-02-24 Dano Kim , Hoseob Seo

In these notes we generalize the Ohsawa's results on the Hartogs extension phenomenon in the complement of effective divisors in K\"ahler manifolds with semipositive non-flat normal bundle. Namely, we prove that the Hartogs extension…

Complex Variables · Mathematics 2025-03-13 S. V. Feklistov

In an influential $L^2$ extension theorem due to Demailly, the finiteness of an $L^2$ norm called the Ohsawa norm determines whether a given holomorphic function can be extended. This result has been further generalized by Zhou and Zhu to…

Complex Variables · Mathematics 2025-05-05 Dano Kim , Xu Wang

Let $X=U/K$ be a compact Hermitian symmetric space, and let $\sE$ be a $U$-homogeneous Hermitian vector bundle on $X$. In a previous paper, we showed that the space of nearly holomorphic sections is well-adapted for harmonic analysis in…

Complex Variables · Mathematics 2013-03-13 Benjamin Schwarz

We prove an $L^2$-$\partial\overline\partial$-Lemma involving smooth square integrable forms on complete K\"ahler manifolds, provided that the unique self-adjoint extension of the Hodge Laplacian on the Hilbert space of $L^2$-forms has a…

Differential Geometry · Mathematics 2026-02-10 Riccardo Piovani

We study the following optimal $L^2$ extension problem of openness type: given a complex manifold $M$, a closed subvariety $S\subset M$ and a holomorphic vector bundle $E\rightarrow M$, for any $L^2$ holomorphic section $f$ defined on some…

Complex Variables · Mathematics 2024-05-22 Wang Xu , Xiangyu Zhou

Hosono obtained sharper estimates of the Ohsawa--Takegoshi $L^2$-extention theorem by allowing the constant depending on the weight function for a domain in $\mathbb{C}$. In this article, we show the higher dimensional case of sharper…

Complex Variables · Mathematics 2021-02-04 Shota Kikuchi

In this article we prove a theorem of Ohsawa-Takegoshi type on compact K\"ahler manifolds. Our arguments follow the "standard" approach for this kind of extension results; however, there are many complications arising from the…

Algebraic Geometry · Mathematics 2011-04-18 Li Yi

We study conditions of H\"ormander's $L^2$-estimate and the Ohsawa-Takegoshi extension theorem. Introducing a twisted version of H\"ormander-type condition, we show a converse of H\"ormander $L^2$-estimate under some regularity assumptions…

Complex Variables · Mathematics 2019-01-09 Genki Hosono , Takahiro Inayama

We prove an extension theorem for roots and logarithms of holomorphic line bundles across strictly pseudoconcave boundaries: they extend in all cases except one, when dimension and Morse index of a critical point is two. In that case we…

Complex Variables · Mathematics 2011-04-19 Sergey Ivashkovich

In very rough terms, the main theorem is that the set, which consists of semistable vector bundles with trivial rational Chern classes and nontrivial kth cohomology on a smooth complex projective variety, is a degeneration of a union of…

alg-geom · Mathematics 2008-02-03 Donu Arapura