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

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We study symplectic geometry of rationally connected $3$-folds. The first result shows that rationally connectedness is a symplectic deformation invariant in dimension $3$. If a rationally connected $3$-fold $X$ is Fano or $b_2(X)=2$, we…

Algebraic Geometry · Mathematics 2019-12-19 Zhiyu Tian

We extend Hacon--M\textsuperscript{c}Kernan's rational chain connectedness theorem to the complex analytic setting. As a consequence, we prove that the fibers of any resolution of singularities of complex analytic kawamata log terminal…

Algebraic Geometry · Mathematics 2026-03-06 Osamu Fujino

Let $M$ be a smooth Fano threefold such that a canonical extension of the tangent bundle is an affine manifold. We show that $M$ is rational homogeneous.

Algebraic Geometry · Mathematics 2022-11-22 Andreas Höring , Thomas Peternell

We study the connectedness of the real locus of smooth geometrically rational Fano threefolds and prove a sufficient criterion of $\mathbb{R}$-rationality.

Algebraic Geometry · Mathematics 2025-07-08 Andrea Fanelli , Frédéric Mangolte

In this paper, we study the structure of Fano fibrations of varieties admitting an int-amplified endomorphism. We prove that if a normal $\mathbb{Q}$-factorial klt projective variety $X$ has an int-amplified endomorphism, then there exists…

Algebraic Geometry · Mathematics 2020-02-05 Shou Yoshikawa

(On the fundamental group of rationnally connected varieties.) I show that the fundamental group of a normal variety which is rationally chain connected is finite. The proof holds in non-zero characteristic. Je d\'emontre que le groupe…

Algebraic Geometry · Mathematics 2007-05-23 Antoine Chambert-Loir

In this paper, we consider the CM line bundle on the K-moduli space, i.e., the moduli space parametrizing K-polystable Fano varieties. We prove it is ample on any proper subspace parametrizing reduced uniformly K-stable Fano varieties which…

Algebraic Geometry · Mathematics 2021-02-22 Chenyang Xu , Ziquan Zhuang

We construct a moduli space of stable projective pairs with a nontrivial action of a connected reductive group. These stable reductive pairs are higher-dimensional analogs of stable n-pointed curves and generalize to the non-commutative…

Algebraic Geometry · Mathematics 2007-05-23 Valery Alexeev , Michel Brion

This work establishes a structure theorem for compact K\"ahler manifolds with semipositive anticanonical bundle. Up to finite \'etale cover, it is proved that such manifolds split holomorphically and isometrically as a product of Ricci flat…

Algebraic Geometry · Mathematics 2018-02-06 Frédéric Campana , Jean-Pierre Demailly , Thomas Peternell

We prove that $\mathbb{Q}$-Fano threefolds of Fano index $\ge 8$ are rational.

Algebraic Geometry · Mathematics 2019-03-19 Yuri Prokhorov

In this note we study properties of partially ample line bundles on simplicial projective toric varieties. We prove that the cone of q-ample line bundles is a union of rational polyhedral cones, and calculate these cones in examples. We…

Algebraic Geometry · Mathematics 2014-09-29 Nathan Broomhead , John Christian Ottem , Artie Prendergast-Smith

We study the anti-canonical ring of a projective variety and we characterise varieties of log Fano type depending on the singularities of these models.

Algebraic Geometry · Mathematics 2013-08-19 Paolo Cascini , Yoshinori Gongyo

We describe the families of minimal rational curves on any complete symmetric variety, and the corresponding varieties of minimal rational tangents (VMRT). In particular, we prove that these varieties are homogeneous and that for…

Algebraic Geometry · Mathematics 2025-05-20 Michel Brion , Shin-young Kim , Nicolas Perrin

We prove that K-polystable log Fano pairs have reductive automorphism groups. In fact, we deduce this statement by establishing more general results concerning the S-completeness and $\Theta$-reductivity of the moduli of K-semistable log…

Algebraic Geometry · Mathematics 2020-12-02 Jarod Alper , Harold Blum , Daniel Halpern-Leistner , Chenyang Xu

In this paper, we advance the classification of toric 2-Fano manifolds by continuing the investigation of the minimal projective bundle dimension $m(X) \in \{1,\dots,\dim(X)\}$ introduced in our previous work. This invariant captures the…

Motivated by the study of Fano type varieties we define a new class of log pairs that we call asymptotically log Fano varieties and strongly asymptotically log Fano varieties. We study their properties in dimension two under an additional…

Algebraic Geometry · Mathematics 2015-09-17 Ivan A. Cheltsov , Yanir A. Rubinstein

We propose an analogue of Dubrovin's conjecture for the case where Fano manifolds have quantum connections of exponential type. It includes the case where the quantum cohomology rings are not necessarily semisimple. The conjecture is…

Algebraic Geometry · Mathematics 2021-01-18 Fumihiko Sanda , Yota Shamoto

We prove a part of Shokurov's conjecture on characterization of toric varieties modulo the minimal model program and adjunction conjecture.

Algebraic Geometry · Mathematics 2010-05-06 Yuri G. Prokhorov

Abstract. In our previous paper arXiv:2210.16008, we show that any prime $\mathbb{Q}$-Fano 3-folds $X$ with only $1/2(1,1,1)$-singularities in certain 5 classes can be embedded as linear sections into bigger dimensional $\mathbb{Q}$-Fano…

Algebraic Geometry · Mathematics 2022-11-15 Hiromichi Takagi

In this talk, I report on three theorems concerning algebraic varieties over a field of characteristic $p>0$. a) over a finite field of cardinal $q$, two proper smooth varieties which are geometrically birational have the same number of…

Algebraic Geometry · Mathematics 2010-04-26 Antoine Chambert-Loir