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Kawakami and the author showed that a projective variety with an int-amplified endomorphism of degree invertible in the base field satisfies Bott vanishing. That was a new way to analyze which varieties have nontrivial endomorphisms. In…

Algebraic Geometry · Mathematics 2025-02-12 Burt Totaro

Regular semisimple Hessenberg varieties are smooth subvarieties of the flag variety, and their examples contain the flag variety itself and the permutohedral variety which is a toric variety. We give a complete classification of Fano and…

Algebraic Geometry · Mathematics 2020-03-30 Hiraku Abe , Naoki Fujita , Haozhi Zeng

In this paper we give a splitting criterion for uniform vector bundles on Fano manifolds covered by lines. As a consequence, we classify low rank uniform vector bundles on Hermitian symmetric spaces and Fano bundles of rank two on…

Algebraic Geometry · Mathematics 2015-03-10 Roberto Munoz , Gianluca Occhetta , Luis E. Sola Conde

The paper proposes and motivates a conjecture on the invariance of cohomological support loci under derived equivalence. It contains a proof in the case of surfaces, and explains further developments and consequences.

Algebraic Geometry · Mathematics 2012-03-22 Mihnea Popa

Quiver flag zero loci are subvarieties of quiver flag varieties cut out by sections of homogeneous vector bundles. We prove the Abelian/non-Abelian Correspondence in this context: this allows us to compute genus zero Gromov--Witten…

Algebraic Geometry · Mathematics 2018-11-13 Elana Kalashnikov

We compute global log canonical thresholds, or equivalently alpha invariants, of birationally rigid orbifold Fano threefolds embedded in weighted projective spaces as codimension two or three. As an important application, we prove that most…

Algebraic Geometry · Mathematics 2016-04-04 In-Kyun Kim , Takuzo Okada , Joonyeong Won

For fixed degree $d\leq 12$, we study the Hilbert scheme of degree $d$ smooth Fano threefolds in their anticanonical embeddings. We use this to classify all possible degenerations of these varieties to toric Fano varieties with at most…

Algebraic Geometry · Mathematics 2019-11-26 Jan Arthur Christophersen , Nathan Owen Ilten

A Mukai variety is a Fano n-fold of index n-2. In this paper we study the fundamental divisor of a Mukai variety with at worst log terminal singularities. The main result is a complete classification of log terminal Mukai varieties which…

alg-geom · Mathematics 2008-02-03 Massimiliano Mella

We characterize smooth irreducible curves $C$ on a smooth hyperquadric $Y$ of $\mathbb{P}^4$ such that the blowup of $Y$ along $C$ is a weak Fano threefold. These are precisely the smooth irreducible curves $C$ of degree $d$ and genus $g$…

Algebraic Geometry · Mathematics 2026-02-12 Anne Schnattinger

We classify smooth Fano threefolds that admit degenerations to toric Fano threefolds with ordinary double points.

Algebraic Geometry · Mathematics 2018-09-11 Sergey Galkin

We prove the existence of good minimal models for any klt algebraically integrable adjoint foliated structure of general type, and that Fano algebraically integrable adjoint foliated structures with total minimal log discrepancies and…

Algebraic Geometry · Mathematics 2025-04-16 Paolo Cascini , Jingjun Han , Jihao Liu , Fanjun Meng , Calum Spicer , Roberto Svaldi , Lingyao Xie

A generalization of S. Mukai's conjecture says that if $X$ is a Fano $n$-fold with Picard number $\rho_X$ and pseudo-index $i_X$, then $\rho_X(i_X-1) \leq n$, with equality if and only if $X \cong (\mathbb{P}^{i_X-1})^{\rho_X}$. In this…

Algebraic Geometry · Mathematics 2017-03-23 Taku Suzuki

We give several examples of pairs of non-isomorphic cubic fourfolds whose Fano varieties of lines are birationally equivalent (and in one example isomorphic). Two of our examples, which are special families of conjecturally irrational…

Algebraic Geometry · Mathematics 2024-12-20 Corey Brooke , Sarah Frei , Lisa Marquand

Let $X$ be a complex smooth Fano variety of dimension $n$. Assume that $X$ admits a birational contraction of an extremal ray. In this paper, we give a classification of such $X$ when the pseudoindex is equal to $\frac{\dim X}{2}$.

Algebraic Geometry · Mathematics 2025-10-22 Kiwamu Watanabe

In our previous work we conjectured - inspired by an algebro-geometric result of Fujita - that the height of an arithmetic Fano variety X of relative dimension $n$ is maximal when X is the projective space $\mathbb{P}^n_{\mathbb{Z}}$ over…

Algebraic Geometry · Mathematics 2024-03-05 Rolf Andreasson , Robert J. Berman

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

Let $X$ be a Gorenstein canonical Fano variety of coindex $4$ and dimension $n$ with $H$ fundamental divisor. Assume $h^0(X, H) \geq n -2$. We prove that a general element of the linear system $|mH|$ has at worst canonical singularities for…

Algebraic Geometry · Mathematics 2022-06-03 Jinhyung Park

Ottem and Rennemo constructed a Fano 4-fold with torsion in $H_2(X, \mathbb Z)$. We simplify the computation of $H_2(X, \mathbb Z)$ and also exhibit 2 lines $L', L''\subset X$ such that $L'- L''$ generates the torsion.

Algebraic Geometry · Mathematics 2023-11-17 János Kollár

Based on the former parts, we classify smooth Fano threefolds of positive characteristic.

Algebraic Geometry · Mathematics 2025-12-04 Hiromu Tanaka

In this note we collect some results on the deformation theory of toric Fano varieties.

Algebraic Geometry · Mathematics 2022-06-22 Andrea Petracci