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Related papers: Notes on rational chain connectedness

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We prove a conjecture of V. V. Shokurov which in particular implies that the fibers of a resolution of a variety with divisorial log terminal singularities are rationally chain connected.

Algebraic Geometry · Mathematics 2007-05-23 Christopher D Hacon , James McKernan

We show that there exists a natural number $p_0$ such that any three-dimensional Kawamata log terminal singularity defined over an algebraically closed field of characteristic $p>p_0$ is rational and in particular Cohen-Macaulay.

Algebraic Geometry · Mathematics 2017-07-19 Christopher Hacon , Jakub Witaszek

Campana introduced a notion of Campana rational connectedness for Campana orbifolds. Given a Campana fibration over a complex curve, we prove that a version of weak approximation for Campana sections holds at places of good reduction when…

Algebraic Geometry · Mathematics 2025-04-24 Qile Chen , Brian Lehmann , Sho Tanimoto

Using deformation theory of rational curves, we prove a conjecture of Sommese on the extendability of morphisms from ample subvarieties when the morphism is a smooth (or mildly singular) fibration with rationally connected fibers. We apply…

Algebraic Geometry · Mathematics 2020-11-23 Tommaso de Fernex , Chung Ching Lau

We prove that the class of log canonical rational singularities is closed under the basic operations of the minimal model program. We also give some supplementary results on the minimal model program for log canonical surfaces.

Algebraic Geometry · Mathematics 2015-03-05 Osamu Fujino

We survey some recent topics on singularities, with a focus on their connection to the minimal model program. This includes the construction and properties of dual complexes, the proof of the ACC conjecture for log canonical thresholds and…

Algebraic Geometry · Mathematics 2017-12-05 Chenyang Xu

In this paper, we give an affirmative answer to a conjecture in the Minimal Model Program. We prove that log $Q$-Fano varieties of dim $n$ are rationally connected. We also study the behavior of the canonical bundles under projective…

Algebraic Geometry · Mathematics 2007-05-23 Qi Zhang

We prove that the link of a complex normal surface singularity is an L--space if and only if the singularity is rational. This via a recent result of Hanselman, J. Rasmussen, S. D. Rasmussen and Watson (proving the conjecture of Boyer,…

Geometric Topology · Mathematics 2015-10-27 András Némethi

We prove that globally $+$-regular varieties are rationally chain connected in dimension three and mixed characteristic with residue field characteristic $p>5$. We also introduce a notion of strongly globally $+$-regular, and show that…

Algebraic Geometry · Mathematics 2026-02-20 Emre Alp Özavcı , Zsolt Patakfalvi , Kevin Tucker , Joe Waldron , Zheng Xu

In this paper we introduce a notion of rational singularities associated to pairs $(X, \ba^t)$ where $X$ is a variety, $\ba$ is an ideal sheaf and $t$ is a nonnegative real number. We prove that most standard results about rational…

Algebraic Geometry · Mathematics 2009-04-28 Karl Schwede , Shunsuke Takagi

It is well known that the exceptional set in a resolution of a rational surface singularity is a tree of rational curves. We generalize the combinatoric part of this statement to higher dimensions and show that the highest cohomologies of…

Algebraic Geometry · Mathematics 2009-04-22 D. A. Stepanov

We generalize the rationality theorem of the accumulation points of log canonical thresholds which was proved by Hacon, M\textsuperscript{c}Kernan, and Xu. Further, we apply the rationality to the ACC problem on the minimal log…

Algebraic Geometry · Mathematics 2024-04-30 Yusuke Nakamura

We discuss the cone and contraction theorem in a suitable complex analytic setting. More precisely, we establish the cone and contraction theorem of normal pairs for projective morphisms between complex analytic spaces. This result is a…

Algebraic Geometry · Mathematics 2023-08-15 Osamu Fujino

We prove that we can always construct strongly minimal linearizations of an arbitrary rational matrix from its Laurent expansion around the point at infinity, which happens to be the case for polynomial matrices expressed in the monomial…

Numerical Analysis · Mathematics 2021-10-26 Froilán M. Dopico , María C. Quintana , Paul Van Dooren

In this work, we show that for a certain class of threefolds in positive characteristics, rational-chain-connectivity is equivalent to supersingularity. The same result is known for K3 surfaces with elliptic fibrations. And there are…

Algebraic Geometry · Mathematics 2019-09-11 Santai Qu

We study weak approximation on rationally connected varieties under an assumption of strong approximation for a "simple" variety or under Schinzel's hypothesis. We also get some unconditional results.

Number Theory · Mathematics 2021-09-10 Dasheng Wei

In this short note we prove that in many cases the failure of a variety to be separably rationally connected is caused by the instability of the tangent sheaf (if there are no other obvious reasons). A simple application of the results…

Algebraic Geometry · Mathematics 2014-07-30 Zhiyu Tian

Assuming the Morrison-Kawamata cone conjecture for the generic fiber of a Calabi-Yau fibration and the abundance conjecture, we show (1) the finiteness of minimal models, (2) the existence of a weak rational polyhedral fundamental domain…

Algebraic Geometry · Mathematics 2023-09-12 Zhan Li

Let X be any generalized flag variety with Picard group of rank one. Given a degree d, consider the Gromov-Witten variety of rational curves of degree d in X that meet three general points. We prove that, if this Gromov-Witten variety is…

Algebraic Geometry · Mathematics 2013-05-27 Anders S. Buch , Pierre-Emmanuel Chaput , Leonardo C. Mihalcea , Nicolas Perrin

This paper is concerned with a sufficient criterion to guarantee that a given foliation on a normal variety has algebraic and rationally connected leaves. Following ideas from a preprint of Bogomolov-McQuillan and using recent works of…

Algebraic Geometry · Mathematics 2009-09-29 Stefan Kebekus , Luis Sola Conde , Matei Toma
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