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Related papers: A remark on minimal Fano threefolds

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We study prime Fano threefolds of genus 12 ($V_{22}$-varieties) with positive-dimensional automorphism groups in positive and mixed characteristic. We classify such varieties over any perfect field. In particular, we prove that…

Algebraic Geometry · Mathematics 2026-01-16 Tetsushi Ito , Akihiro Kanemitsu , Teppei Takamatsu , Yuuji Tanaka

We study semi-stable degenerations of quasi-Fano varieties to unions of two pieces. We conjecture that the higher rank Landau-Ginzburg models mirror to these two pieces can be glued together to lower rank Landau-Ginzburg models which are…

Algebraic Geometry · Mathematics 2026-01-05 Charles F. Doran , Jordan Kostiuk , Fenglong You

We propose a general approach to classification problems in algebraic geometry via mirror duality. For Fano threefolds, a modularity conjecture describes small quantum cohomology and predicts the values of certain Gromov-Witten invariants.

Algebraic Geometry · Mathematics 2007-05-23 V. Golyshev

In this paper, we provide examples of Sarkisov links of type II between complex projective Fano threefolds $X$ with $\rho(X) = 1$. To show examples of these links, we study smooth weak Fano threefolds with extremal rays of type $E$. We…

Algebraic Geometry · Mathematics 2014-01-07 Joseph W. Cutrone , Nicholas A. Marshburn

We prove Weak Borisov--Alexeev--Borisov Conjecture in dimension three which states that the anti-canonical volume of an $\epsilon$-klt log Fano pair of dimension three is bounded from above.

Algebraic Geometry · Mathematics 2022-07-11 Chen Jiang

A well-known conjecture of Orlov asks whether the existence of a full exceptional collection implies rationality of the underlying variety. We prove this conjecture for arithmetic toric varieties over general fields. We also investigate a…

Algebraic Geometry · Mathematics 2024-09-27 Matthew R. Ballard , Alexander Duncan , Alicia Lamarche , Patrick K. McFaddin

In this paper, we study the explicit geometry of threefolds, in particular, Fano varieties. We find an explicitly computable positive integer $N$, such that all but a bounded family of Fano threefolds have $N$-complements. This result has…

Algebraic Geometry · Mathematics 2023-11-14 Caucher Birkar , Jihao Liu

We prove the Manin-Peyre conjecture for the number of rational points of bounded height outside of a thin subset on a family of Fano threefolds of bidegree (1,2). The proof uses a mixture of the circle method and techniques from the…

Number Theory · Mathematics 2022-07-18 Dante Bonolis , Tim Browning , Zhizhong Huang

In this paper we prove that given a pair $(X,D)$ of a threefold $X$ and a boundary divisor $D$ with mild singularities, if $(K_X+D)$ is movable, then the orbifold second Chern class $c_2$ of $(X,D)$ is pseudo-effective. This generalizes the…

Algebraic Geometry · Mathematics 2022-08-04 Erwan Rousseau , Behrouz Taji

Let $X$ be a hyperk\"ahler variety, and assume $X$ has a non-symplectic automorphism $\sigma$ of order $>{1\over 2}\dim X$. Bloch's conjecture predicts that the quotient $X/<\sigma>$ should have trivial Chow group of $0$-cycles. We verify…

Algebraic Geometry · Mathematics 2017-12-19 Robert Laterveer

We give a proof of Mukai's Theorem on the existence of certain exceptional vector bundles on prime Fano threefolds. To our knowledge this is the first complete proof in the literature. The result is essential for Mukai's biregular…

Algebraic Geometry · Mathematics 2025-09-26 Arend Bayer , Alexander Kuznetsov , Emanuele Macrì

Small codimensional embedded manifolds defined byequations of small degree are Fano and covered by lines. They are complete intersections exactly when the variety of lines through a general point is so and has the right codimension. This…

Algebraic Geometry · Mathematics 2014-11-25 Paltin Ionescu , Francesco Russo

The map given by the anticanonical bundle of a Fano manifold is investigated with respect to a number of natural notions of higher order embeddings of projective manifolds. This is of importance in the understanding of higher order…

alg-geom · Mathematics 2007-05-23 M. C. Beltrametti , S. Di Rocco , A. J. Sommese

The Manin-Peyre conjecture is established for a class of smooth spherical Fano varieties of semisimple rank one. This includes all smooth spherical Fano threefolds of type T as well as some higher-dimensional smooth spherical Fano…

Number Theory · Mathematics 2023-12-04 Valentin Blomer , Jörg Brüdern , Ulrich Derenthal , Giuliano Gagliardi

Let $X$ be a hyperk\"ahler variety, and assume that $X$ admits a non-symplectic automorphism $\sigma$ of order $k>{1\over 2}\dim X$. Bloch's conjecture predicts that the quotient $X/<\sigma>$ should have trivial Chow group of $0$-cycles. We…

Algebraic Geometry · Mathematics 2018-02-21 Robert Laterveer

In this article we discuss some numerical parts of the mirror conjecture. For any 3 - dimensional Calabi - Yau manifold author introduces a generalization of the Casson invariant known in 3 - dimensional geometry, which is called Casson -…

Algebraic Geometry · Mathematics 2007-05-23 Andrey N. Tyurin

Property $\mathcal{O}$ for an arbitrary complex, Fano manifold $X$, is a statement about the eigenvalues of the linear operator obtained from the quantum multiplication of the anticanonical class of $X$. Conjecture $\mathcal{O}$ is a…

Algebraic Geometry · Mathematics 2020-12-01 Lela Bones , Garrett Fowler , Lisa Schneider , Ryan M. Shifler

We prove that the ACC conjecture for minimal log discrepancies holds for threefolds in $[1-\delta,+\infty)$, where $\delta>0$ only depends on the coefficient set. We also study Reid's general elephant for pairs, and show Shokurov's…

Algebraic Geometry · Mathematics 2022-02-16 Jingjun Han , Jihao Liu , Yujie Luo

We study quartic double fivefolds from the perspective of Fano manifolds of Calabi-Yau type and that of exceptional quaternionic representations. We first prove that the generic quartic double fivefold can be represented, in a finite number…

Algebraic Geometry · Mathematics 2017-10-13 Roland Abuaf

We show that the moduli space of elliptic curves of minimal degree in a general Fano variety of lines of a cubic fourfold is a non-singular curve of genus $631$. The curve admits a natural involution with connected quotient. We find that…

Algebraic Geometry · Mathematics 2020-01-20 Denis Nesterov , Georg Oberdieck