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Related papers: Partially ample line bundles and base loci

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In the context of partially ordered vector spaces one encounters different sorts of order convergence and order topologies. This article will investigate these notions and their relations. In particular we study and relate the order…

Functional Analysis · Mathematics 2019-10-25 Till Hauser

A necessary and sufficient condition is given for semi-ampleness of a numerically effective (nef) and big line bundle in positive characteristic. One application is to the geometry of the universal stable curve over M_g, specifically, the…

Algebraic Geometry · Mathematics 2016-09-07 Seán Keel

In this work, we investigate the positivity of logarithmic and orbifold cotangent bundles along hyperplane arrangements in projective spaces. We show that a very interesting example given by Noguchi (as early as in 1986) can be pushed…

Algebraic Geometry · Mathematics 2020-08-27 Lionel Darondeau , Erwan Rousseau

Given a covering f: X \to Y of projective manifolds, we consider the vector bundle E on Y given as the dual of f_*(\O_X) / \O_Y. This vector bundles often has positivity properties, e.g. E is ample when Y is projective space by a theorem of…

Algebraic Geometry · Mathematics 2007-05-23 Thomas Peternell , Andrew J. Sommese

New definitions of rack and quandle modules are introduced, and shown to generalise the definitions previously studied by Andruskiewitsch, Etingof and Grana. This new construct is shown to coincide with Beck's general definition of a module…

Category Theory · Mathematics 2007-05-23 Nicholas Jackson

We study the positivity of CM line bundles on the coarse moduli space of Kawamata log terminal (klt) good minimal models with Kodaira dimension one. We prove that the seminormalization of the moduli space is quasi-projective under a mild…

Algebraic Geometry · Mathematics 2026-01-27 Masafumi Hattori

We study matrix inequalities involving partial traces for positive semidefinite block matrices. First of all, we present a new method to prove a celebrated result of Choi [Linear Algebra Appl. 516 (2017)]. Our method also allows us to prove…

Functional Analysis · Mathematics 2024-04-09 Yongtao Li

We prove that the CM line bundle is ample on the proper moduli space which parametrizes KSBA stable varieties.

Algebraic Geometry · Mathematics 2016-02-08 Zsolt Patakfalvi , Chenyang Xu

Let $X$ be a projective nonsingular toric 3-fold with a surjective torus equivariant morphism onto the projective line. Then we prove that an ample line bundle on $X$ is always normally generated.

Algebraic Geometry · Mathematics 2023-09-21 Shoetsu Ogata

We give an example of a compact Levi-flat CR 3-manifold with a positive-along-leaves CR line bundle which is not ample with respect to transversely infinitely differentiable CR sections. This example shows that we cannot improve the…

Complex Variables · Mathematics 2014-03-14 Masanori Adachi

The bad locus and the rude locus of an ample and base point free linear system on a smooth complex projective variety are introduced and studied. The bad locus is defined as the set of points that force divisors through them to be…

Algebraic Geometry · Mathematics 2007-05-23 Gian Mario Besana , Sandra Di Rocco , Antonio Lanteri

In this note we generalize a criterion within the concept of infinite dense lineability due to Calder\'on-Moreno, Gerlach-Mena and Prado-Bassas. We also introduce and explore some local notions of lineability.

Functional Analysis · Mathematics 2024-06-04 Anselmo Raposo , Geivison Ribeiro

In this paper the concept of a partial cone metric space is investigated, some continuity type theorems, and fixed point theorems of contractive mappings in this generalized setting are proved as well as some theorems related to topological…

General Topology · Mathematics 2012-09-20 Ayse Sonmez

General results on multiplicative lattices found recently by Facchini, Finocchiaro and Janelidze have been studied in the particular case of groups by Facchini, de Giovanni and Trombetti. In this paper we prove that these results hold not…

Group Theory · Mathematics 2022-04-26 Alberto Facchini

A result due to Cho, Miyaoka, Shepherd-Barron [CMSB] and Kebekus [Ke] provides a numerical characterization of projective spaces. More recently, Dedieu and H\"oring [DH] gave a characterization of smooth quadrics based on similar arguments.…

Algebraic Geometry · Mathematics 2024-11-27 Bruno Dewer

Classification theory and the study of projective varieties which are covered by rational curves of minimal degrees naturally leads to the study of families of singular rational curves. Since families of arbitrarily singular curves are hard…

Algebraic Geometry · Mathematics 2007-05-23 Stefan Kebekus

We show that the $\partial\bar{\partial}$-lemma holds for the non-K\"ahler compact complex manifolds of dimension three with trivial canonical bundle constructed by Clemens as deformations of Calabi-Yau threefolds contracted along smooth…

Algebraic Geometry · Mathematics 2020-03-17 Robert Friedman

We call a partially hyperbolic diffeomorphism \emph{partially volume expanding} if the Jacobian restricted to any hyperplane that contains the unstable bundle $E^u$ is larger than $1$. This is a $C^1$ open property. We show that any…

Dynamical Systems · Mathematics 2021-02-24 Shaobo Gan , Ming Li , Marcelo Viana , Jiagang Yang

We study PL bordism theories from a quantitative perspective. Such theories include those of PL manifolds, ordinary homology theory, as well as various more exotic theories such as bordism of Witt spaces. In all these cases we show that a…

Geometric Topology · Mathematics 2026-02-25 Fedor Manin , Bena Tshishiku , Shmuel Weinberger

In a recent paper, G. Cz\'edli and E.\,T. Schmidt present a structure theorem for planar semimodular lattices. In this note, we present an alternative proof.

Rings and Algebras · Mathematics 2022-08-08 G. Grätzer
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