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Related papers: On toric Fano fibrations

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We prove a conjecture of Batryev which states that the family of all Fano varieties with kawamata log terminal singularities and fixed index, forms a bounded family.

Algebraic Geometry · Mathematics 2009-09-29 James McKernan

I state a conjecture asserting that for all generic klt Fano varieties X, there exists a generalised cluster variety U and a surjection from the set of torus charts on U to the set of toric specializations of X. I prove the conjecture in…

Algebraic Geometry · Mathematics 2023-10-02 Alessio Corti

We show that the number of deformation types of canonically polarized manifolds over an arbitrary variety with proper singular locus is finite, and that this number is uniformly bounded in any finite type family of base varieties. As a…

Algebraic Geometry · Mathematics 2019-04-08 Sandor J. Kovacs , Max Lieblich

It is conjectured that the base varieties of the Iitaka fibrations are bounded when the Iitaka volumes are bounded above. We confirm this conjecture for Iitaka $\epsilon$-lc Fano type fibrations.

Algebraic Geometry · Mathematics 2023-01-26 Zhan Li

The purpose of this paper is to give basic tools for the classification of nonsingular toric Fano varieties by means of the notions of primitive collections and primitive relations due to Batyrev. By using them we can easily deal with…

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

We prove that normal projective stable families of maximal variation, of fixed dimension, and with bounded adjoint volume are birationally bounded. This is a consequence of a substantially stronger statement, formulated a priori…

Algebraic Geometry · Mathematics 2026-04-28 Paolo Cascini , Jihao Liu , Calum Spicer , Roberto Svaldi

We prove the boundedness of complements for Fano type generalized pairs (with the boundary coefficient set $[0,1]$) after Shokurov.

Algebraic Geometry · Mathematics 2025-07-31 Guodu Chen , Jingjun Han , Yang He , Lingyao Xie

In [BK], it is shown that the Turaev-Viro invariants defined for a spherical fusion category $\mathcal{A}$ extends to invariants of 3-manifolds with corners. In [Kir], an equivalent formulation for the 2-1 part of the theory (2-manifolds…

Quantum Algebra · Mathematics 2022-11-01 Alexander Kirillov , Ying Hong Tham

In a first result, we describe all finitely generated factorial algebras over an algebraically closed field of characteristic zero that come with an effective multigrading of complexity one by means of generators and relations. This enables…

Algebraic Geometry · Mathematics 2011-04-26 Juergen Hausen , Elaine Herppich , Hendrik Süß

A conjecture of Pukhlikov states that a smooth Fano variety of dimension at least four and index one is birationally rigid. We show that a general member of the linear system given by the ample generator of the Picard group of the moduli…

Algebraic Geometry · Mathematics 2007-05-23 Ana-Maria Castravet

A consistent exposition of the arguments and constructions of the method of maximal singularities, the aim of which is to describe birational iso/automorphisms of Fano varieties and Fano fibrations. The principal elements of the method are…

Algebraic Geometry · Mathematics 2007-05-23 Aleksandr V. Pukhlikov

Every finitely presented group is the fundamental group of the total space of a Lefschetz fibration. This follows from results of Gompf and Donaldson, and was also proved by Amoros-Bogomolov-Katzarkov-Pantev. We give another proof by…

Geometric Topology · Mathematics 2007-05-23 Mustafa Korkmaz

We develop a theory of multi-stage degenerations of toric varieties over finite rank valuation rings, extending the Mumford--Gubler theory in rank one. Such degenerations are constructed from fan-like structures over totally ordered abelian…

Algebraic Geometry · Mathematics 2018-05-16 Tyler Foster , Dhruv Ranganathan

We investigate birational boundedness of Fano varieties and Fano fibrations. We establish an inductive step towards birational boundedness of Fano fibrations via conjectures related to boundedness of Fano varieties and Fano fibrations. As…

Algebraic Geometry · Mathematics 2019-12-02 Chen Jiang

We give a necessary and sufficient condition for the nonsingular projective toric variety associated to a finite simple graph to be Fano or weak Fano in terms of the graph.

Algebraic Geometry · Mathematics 2016-05-17 Yusuke Suyama

The main result of this note is an effective uniform bound for the number of deformation types of certain nonisotrivial families of canonically polarized manifolds. It extends the author's earlier such bound for the classical Shafarevich…

Algebraic Geometry · Mathematics 2010-06-21 Gordon Heier

In this article, we prove a toroidalization principle for finite actions on klt singularities. As an application, we prove that the Jordan property for the regional fundamental group of klt singularities can be realized geometrically: by…

Algebraic Geometry · Mathematics 2021-09-21 Joaquín Moraga

We introduce an analogue of the Novikov Conjecture on higher signatures in the context of the algebraic geometry of (nonsingular) complex projective varieties. This conjecture asserts that certain "higher Todd genera" are birational…

Algebraic Geometry · Mathematics 2011-03-10 Jonathan Rosenberg

A conic bundle is a contraction $X\to Z$ between normal varieties of relative dimension $1$ such that $-K_X$ is relatively ample. We prove a conjecture of Shokurov which predicts that, if $X\to Z$ is a conic bundle such that $X$ has…

Algebraic Geometry · Mathematics 2022-07-12 Jingjun Han , Chen Jiang , Yujie Luo

In this paper a large class of Fano double quadrics and cubics are shown to be factorial and birationally superrigid, in particular they admit no non-trivial structure of a fibration with rationally connected fibres and are therefore…

Algebraic Geometry · Mathematics 2018-01-30 Ewan Johnstone