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Related papers: Boundedness theorem for Fano log-threefolds

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We investigate the boundedness problem for log Calabi-Yau fibrations whose bases and general fibers are bounded. We prove that the total spaces of log Calabi-Yau fibrations are bounded in codimension one after fixing some natural…

Algebraic Geometry · Mathematics 2025-04-08 Xiaowei Jiang , Junpeng Jiao , Minzhe Zhu

This paper studies the defect of terminal Gorenstein Fano 3 folds. I determine a bound on the defect of terminal Gorenstein Fano 3-folds of Picard rank 1 that do not contain a plane. I give a general bound for quartic 3-folds and indicate…

Algebraic Geometry · Mathematics 2009-08-24 Anne-Sophie Kaloghiros

We prove rationality criteria over algebraically non-closed fields of characteristic $0$ for five out of six types of geometrically rational Fano threefolds of Picard number $1$ and geometric Picard number bigger than $1$. For the last type…

Algebraic Geometry · Mathematics 2022-08-04 Alexander Kuznetsov , Yuri Prokhorov

We shall investigate index 1 covers of 2-dimensional log terminal singularities. The main result is that the index 1 cover is canonical if the characteristic of the base field is different from 2 or 3. We also give some counterexamples in…

Algebraic Geometry · Mathematics 2007-05-23 Yujiro Kawamata

In this article, we study how the rationality of a Fano threefold is reflected in its standard mirror Landau-Ginzburg model and its deformations. The main result is that a Fano threefold is rational if and only if the monodromy around every…

Algebraic Geometry · Mathematics 2025-10-27 Sukjoo Lee , Victor Przyjalkowski

For any closed Riemannian three-manifold, we prove that for any sequence of closed embedded minimal surfaces with uniformly bounded index, the genus can only grow at most linearly with respect to the area.

Differential Geometry · Mathematics 2018-12-31 Davi Maximo

We generalize the equivariant intermediate Jacobian torsor obstruction over $\mathbb{C}$ to algebraically closed fields of characteristic zero. It is an obstruction to the (projective) linearizability problem of finite group actions on…

Algebraic Geometry · Mathematics 2026-01-13 Shuto Abe

In the representation theory of real reductive Lie groups, many objects have finiteness properties. For example, the lengths of Verma modules and principal series representations are finite, and more precisely, they are bounded. In this…

Representation Theory · Mathematics 2021-09-22 Masatoshi Kitagawa

We prove a boundedness result for klt pairs $(X,B)$ such that $K_X+B\equiv 0$ and $B$ is big. As a consequence we obtain a positive answer to the Effective Iitaka Fibration Conjecture for klt pairs with big boundary.

Algebraic Geometry · Mathematics 2014-10-31 Christopher D. Hacon , Chenyang Xu

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 produce a list of 64 families of Fano fourfolds of K3 type, extracted from our database of at least 634 Fano fourfolds constructed as zero loci of general global sections of completely reducible homogeneous vector bundles on products of…

Algebraic Geometry · Mathematics 2025-05-23 Marcello Bernardara , Enrico Fatighenti , Laurent Manivel , Fabio Tanturri

We prove the following main result: Let X be a Fano 3-fold with terminal Q-factorial singularities and X does not have a small extremal ray and a face of Kodaira dimension 1 or 2 for Mori polyhedron of X. Then the Picard number \rho (X) <…

alg-geom · Mathematics 2008-02-03 Viacheslav V. Nikulin

One measure of the complexity of a first-order theory, and similarly a type, is the complexity of the formulas required to axiomatize it. We say a theory is bounded if there is an axiomatization involving only $\forall_n$-formulas for some…

Logic · Mathematics 2026-04-29 Hongyu Zhu

In this note, we aim to prove the finite semi-algebraic chamber decomposition theorem for K-semi(poly)stability under the assumption of the log boundedness of K-semistable degenerations. This boundedness assumption is naturally arising from…

Algebraic Geometry · Mathematics 2025-09-22 Chuyu Zhou

We discuss various results on Hilbert schemes of lines and conics and automorphism groups of smooth Fano threefolds with Picard rank 1. Besides a general review of facts well known to experts, the paper contains some new results, for…

Algebraic Geometry · Mathematics 2018-09-05 Alexander Kuznetsov , Yuri Prokhorov , Constantin Shramov

We find all K-polystable limits of smooth Fano threefolds in family 3.10.

Algebraic Geometry · Mathematics 2026-04-01 Ivan Cheltsov , Alan Thompson

We show that the minimal log discrepancy of any isolated Fano cone singularity is at most the dimension of the variety. This is based on its relation with dimensions of moduli spaces of orbifold rational curves. We also propose a…

Algebraic Geometry · Mathematics 2025-02-18 Chi Li , Zhengyi Zhou

For families of continuous plurisubharmonic functions we show that, in a local sense, separately bounded above implies bounded above.

Complex Variables · Mathematics 2017-08-08 Łukasz Kosiński , Étienne Martel , Thomas Ransford

The goal of this short note is to point out that every Fano manifold with a nef tangent bundle possesses an almost K{\"a}hler-Einstein metric, in a weak sense. The technique relies on a regularization theorem for closed positive (1,…

Complex Variables · Mathematics 2018-02-07 Jean-Pierre Demailly

We give a lower bound of the $\delta$-invariants of ample line bundles in terms of Seshadri constants. As applications, we prove the uniform K-stability of infinitely many families of Fano hypersurfaces of arbitrarily large index, as well…

Algebraic Geometry · Mathematics 2022-04-28 Hamid Abban , Ziquan Zhuang
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