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Related papers: Boundedness theorem for Fano log-threefolds

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We prove a conjecture due to V.V. Shokurov on the boundedness of $\epsilon$-log canonical complements on surfaces. As an application we give a new proof to the boundedness of weak log Fano surfaces.

Algebraic Geometry · Mathematics 2007-05-23 Caucher Birkar

We investigate the rationality problem for $\mathbf{Q}$-Fano threefolds of Fano index $\ge 2$.

Algebraic Geometry · Mathematics 2026-01-22 Yuri Prokhorov

In this article, we prove that any Q-Calabi-Yau 3-fold with only ordinary terminal singularities and any Q-Fano 3-fold of Fano index 1 with only terminal singularities have Q-smoothings.

Algebraic Geometry · Mathematics 2007-05-23 Tatsuhiro Minagawa

We show that any union of slc strata of a Fano log pair with semi-log canonical singularities is simply connected. In particular, Fano log pairs with semi-log canonical singularities are simply connected, which confirms a conjecture of the…

Algebraic Geometry · Mathematics 2017-12-12 Osamu Fujino , Wenfei Liu

A main purpose of this paper is to prove that the class of finite dimensional algebras which verify Han's conjecture is closed under split bounded extensions.

K-Theory and Homology · Mathematics 2021-03-01 Claude Cibils , Marcelo Lanzilotta , Eduardo N. Marcos , Andrea Solotar

In the present paper we discuss stability of the tanget bundle of a Fano n-fold of index >= n-2 and b_2=1. For example, we prove that all Fano 4-folds with b_2=1 have stable tangent bundle. For this purpose we prove some vanishing theorems…

alg-geom · Mathematics 2008-02-03 Thomas Peternell , Jaroslaw A. Wisniewski

Let $(X,\Delta)$ be an $n$-dimensional $\epsilon$-klt log $\QQ$-Fano pair. We give an upper bound for the volume ${\rm Vol}(-(K_X+\Delta))=(-(K_X+\Delta))^n$ when $n=2$ or $n=3$ and $X$ is {$\QQ$-factorial} of $\rho(X)=1$. This bound is…

Algebraic Geometry · Mathematics 2012-04-13 Ching-Jui Lai

We investigate when the fundamental group of the smooth part of a K3 surface or Enriques surface with Du Val singularities, is finite. As a corollary we give an effective upper bound for the order of the fundamental group of the smooth part…

Algebraic Geometry · Mathematics 2007-05-23 J. Keum , D. -Q. Zhang

Let $(X,D)$ be log canonical pair such $\dim X = 3$ and the divisor $-(K_X + D)$ is nef and big. For a special class of such $(X,D)$'s we prove that the linear system $|-n(K_{X}+D)|$ is free for $n \gg 0$.

Algebraic Geometry · Mathematics 2010-02-01 Ilya Karzhemanov

In this paper, we prove various results on boundedness and singularities of Fano fibrations and of Fano type fibrations. A Fano fibration is a projective morphism $X\to Z$ of algebraic varieties with connected fibres such that $X$ is Fano…

Algebraic Geometry · Mathematics 2022-09-20 Caucher Birkar

In a work of Costa and Mir\'{o}-Roig state the following conjecture: Every smooth complete toric Fano variety has a full strongly exceptional collection of line bundles. The goal of this article is to prove it for toric Fano 3-folds.

Algebraic Geometry · Mathematics 2010-12-30 Alessandro Bernardi , Sofia Tirabassi

The aim of this note is to settle some foundational questions about the behavior of birational rigidity in extensions of algebraically closed fields.

Algebraic Geometry · Mathematics 2008-09-08 János Kollár

We prove a finiteness result for the $\partial$-patterned guts decomposition of all 3-manifolds obtained by splitting a given orientable, irreducible and $\partial$-irreducible 3-manifold along a closed incompressible surface. Then using…

Geometric Topology · Mathematics 2011-06-01 Michel Boileau , J. Hyam Rubinstein , Shicheng Wang

We prove a structure theorem for non-isomorphic endomorphisms of weak Q-Fano threefolds, or more generally for threefolds with big anti-canonical divisor. Also provided is a criterion for a fibred rationally connected threefold to be…

Algebraic Geometry · Mathematics 2018-09-24 De-Qi Zhang

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

The main theorem states that any complete connected Riemannian manifold of bounded geometry can be isometrically realized as a leaf with trivial holonomy in a compact Riemannian foliated space.

Geometric Topology · Mathematics 2016-12-21 Jesús A. Álvarez López , Ramón Barral Lijó

We study global log canonical thresholds on anticanonically embedded quasismooth weighted Fano threefold hypersurfaces having terminal quotient singularities to prove the existence of a Kahler-Einstein metric on most of them, and to produce…

Algebraic Geometry · Mathematics 2007-06-18 Ivan Cheltsov

We prove a finiteness theorem for subgroups of bounded rank in hyperbolic $3$-manifold groups. As a consequence, we show that every bounded rank covering tower of closed hyperbolic $3$-manifolds is a tower of finite covers associated to a…

Geometric Topology · Mathematics 2024-04-03 Ian Biringer

Given an orientation-preserving and area-preserving homeomorphism $f$ of the sphere, we prove that every point which is in the common boundary of three pairwise disjoint invariant open topological disks must be a fixed point. As an…

Dynamical Systems · Mathematics 2018-06-05 Andres Koropecki , Patrice Le Calvez , Fabio Armando Tal

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
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