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Related papers: Rational connectedness of log $Q$-Fano varieties

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We study the Picard rank of smooth toric Fano varieties possessing families of minimal rational curves of given degree. We discuss variants of a conjecture of Chen-Fu-Hwang and prove a version of their statement that recovers the original…

Algebraic Geometry · Mathematics 2022-10-03 Roya Beheshti , Ben Wormleighton

We study the rationality of some geometrically rational three-dimensional conic and quadric surface bundles, defined over the reals and more general real closed fields, for which the real locus is connected and the intermediate Jacobian…

Algebraic Geometry · Mathematics 2026-04-22 Olivier Benoist , Alena Pirutka

In this paper we prove Homological Projective Duality for crepant categorical resolutions of several classes of linear determinantal varieties. By this we mean varieties that are cut out by the minors of a given rank of a n x m matrix of…

Algebraic Geometry · Mathematics 2016-04-12 Marcello Bernardara , Michele Bolognesi , Daniele Faenzi

Varieties with log terminal and log canonical singularities are considered in the Minimal Model Program, see \cite{...} for introduction. In \cite{shokurov:hyp} it was conjectured that many of the interesting sets, associated with these…

alg-geom · Mathematics 2015-06-30 Valery Alexeev

We compare the minimal model of a log canonical pair with the minimal model of its reduced boundary. These results are then used to study the existence of the minimal model of a semi-log-canonical pair using its normalization.

Algebraic Geometry · Mathematics 2017-09-13 Florin Ambro , János Kollár

We consider a finite collection of line bundles $\Phi$ introduced by Bondal on a smooth, projective toric variety $X$. For any coherent sheaf $F$ on $X$, we construct minimal resolutions of $F$ by line bundles in $\Phi$, up to twist, with…

Algebraic Geometry · Mathematics 2024-11-28 David Favero , Mykola Sapronov

In this paper, we develop a theory of pseudo-effective sheaves on normal projective varieties. As an application, by running the minimal model program, we show that projective klt varieties with pseudo-effective tangent sheaf can be…

Algebraic Geometry · Mathematics 2026-05-27 Shin-ichi Matsumura

We give a complete classification of complex Q-homology projective planes with isolated rational double point singularities and numerically trivial canonical bundle. There are 31 types, and each has one-dimensional moduli. In fact, all…

Algebraic Geometry · Mathematics 2016-11-14 Matthias Schuett

We prove existence of flips for log canonical foliated pairs of rank one on a Q-factorial projective klt threefold. This, in particular, provides a proof of the existence of a minimal model for a rank one foliation on a threefold for a…

Algebraic Geometry · Mathematics 2025-10-01 Paolo Cascini , Calum Spicer

We obtain a sufficient condition for a Fano threefold with terminal singularities to have a conic bundle structure.

Algebraic Geometry · Mathematics 2022-02-02 Yuri Prokhorov

We study relative log canonical pairs with relatively trivial log canonical divisors. We fix such a pair $(X,\Delta)/Z$ and establish the minimal model theory for the pair $(X,\Delta)$ assuming the minimal model theory for all Kawamata log…

Algebraic Geometry · Mathematics 2017-11-21 Kenta Hashizume

We investigate relative holomorphic connections on a principal bundle over a family of compact complex manifolds. A sufficient condition is given for the existence of a relative holomorphic connection on a holomorphic principal bundle over…

Algebraic Geometry · Mathematics 2023-05-24 Mainak Poddar , Anoop Singh

Generalizing the well-known Shafarevich hyperbolicity conjecture, it has been conjectured by Viehweg that a quasi-projective manifold that admits a generically finite morphism to the moduli stack of canonically polarized varieties is…

Algebraic Geometry · Mathematics 2019-12-19 Stefan Kebekus , Sandor J. Kovacs

We construct exceptional Fano varieties with the smallest known minimal log discrepancies in all dimensions. These varieties are well-formed hypersurfaces in weighted projective space. Their minimal log discrepancies decay doubly…

Algebraic Geometry · Mathematics 2024-06-07 Louis Esser , Jihao Liu , Chengxi Wang

We prove that every quasi-projective semi log canonical pair has a quasi-log structure with several good properties. It implies that various vanishing theorems, torsion-free theorem, and the cone and contraction theorem hold for semi log…

Algebraic Geometry · Mathematics 2013-10-29 Osamu Fujino

Let G be a connected linear algebraic group over an algebraically closed field k, and let H be a connected closed subgroup of G. We prove that the homogeneous variety G/H is a rational variety over k whenever H is solvable, or when dim(G/H)…

Algebraic Geometry · Mathematics 2018-09-24 CheeWhye Chin , De-Qi Zhang

The Borel-Weil-Bott theorem describes the cohomology of line bundles over flag varieties. Here, one generalizes this theorem to a wider class of projective varieties : the wonderful varieties of minimal rank.

Algebraic Geometry · Mathematics 2007-05-23 Alexis Tchoudjem

Recently L. Nicolaescu and the author formulated a conjecture which relates the geometric genus of a complex analytic normal surface singularity (whose link $M$ is a rational homology sphere) with the Seiberg-Witten invariant of $M$…

Algebraic Geometry · Mathematics 2016-09-07 Andras Nemethi

We prove that the abundance conjecture holds on a variety $X$ with mild singularities if $X$ has many reflexive differential forms with coefficients in pluricanonical bundles, assuming the Minimal Model Program in lower dimensions. This…

Algebraic Geometry · Mathematics 2025-08-22 Vladimir Lazić , Thomas Peternell

We show that the set of rationally connected projective varieties $X$ of a fixed dimension such that $(X,B)$ is klt, and $-l(K_X+B)$ is Cartier and nef for some fixed positive integer $l$, is bounded modulo flops.

Algebraic Geometry · Mathematics 2024-12-03 Jingjun Han , Chen Jiang