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Related papers: Singularities on Fano fibrations and beyond

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It is conjectured that the canonical models of varieties (not of general type) are bounded when the Iitaka volume is fixed. We confirm this conjecture when the general fibers of the corresponding Iitaka fibration are in a fixed bounded…

Algebraic Geometry · Mathematics 2025-09-17 Junpeng Jiao

We prove finiteness of hyperkaehler Lagrangian fibrations in any fixed dimension with fixed Fujiki constant and discriminant of the Beauville-Bogomolov-Fujiki lattice, up to deformation. We also prove finiteness of hyperk\"ahler Lagrangian…

Algebraic Geometry · Mathematics 2016-06-08 Ljudmila Kamenova

We discuss the role of hyperelliptic fibrations in F-theory. For each even integer $n$ we give a noncompact Calabi--Yau threefold $X$ containing a hyperelliptically fibered surface $Y$, such that $X$ and $Y$ are homotopy equivalent and…

High Energy Physics - Theory · Physics 2025-03-06 E. Ballico , E. Gasparim , M. P. García del Moral , C. las Heras

We study the interaction between Fourier-Mukai transforms and perverse filtrations for a certain class of dualizable abelian fibrations. Multiplicativity of the perverse filtration and the "Perverse $\supset$ Chern" phenomenon for these…

Algebraic Geometry · Mathematics 2025-10-09 Davesh Maulik , Junliang Shen , Qizheng Yin

We prove that a fibration X \to \Bbb P_1, the general fiber of which is a smooth Fano threefold, is rationally connected. The proof is based on a generalization of Tsen's classical theorem: a fibration X/C over a curve the general fiber of…

Algebraic Geometry · Mathematics 2015-06-26 Frederic Campana , Thomas Peternell , Aleksandr Pukhlikov

We prove that up to birational equivalence, there exists only a finite number of families of Calabi-Yau threefolds (i.e. a threefold with trivial canonical class and factorial terminal singularities) which have an elliptic fibration to a…

alg-geom · Mathematics 2008-02-03 M. Gross

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 formulate some precise conjectures concerning the existence and structure of supersymmetric T3 fibrations of Calabi-Yau threefolds, and describe how these conjectural fibrations would give rise to the Strominger-Yau-Zaslow version of…

Algebraic Geometry · Mathematics 2010-10-29 David R. Morrison

We study local, global and local-to-global properties of threefolds with certain singularities. We prove criteria for these threefolds to be rational homology manifolds and conditions for threefolds to satisfy rational Poincar\'e duality.…

Algebraic Geometry · Mathematics 2018-04-10 Antonella Grassi , Timo Weigand , with an Appendix by V. Srinivas

We relate the Morrison-Kawamata cone conjecture for Calabi-Yau fiber spaces to the existence of Shokurov polytopes. For K3 fibrations, the existence of (weak) fundamental domains for movable cones is established. The relationship between…

Algebraic Geometry · Mathematics 2025-11-05 Zhan Li , Hang Zhao

We will use flat divisors, and canonically associated singular holomorphic foliations, to investigate some of the geometry of compact complex manifolds. The paper is mainly concerned with three distinct problems: the existence of…

Algebraic Geometry · Mathematics 2010-04-20 Jorge Vitorio Pereira

For a birational analogue of minimal elliptic surfaces X/Y, the singularities of the fibers define a log structure in codimension one on Y. Via base change, we have a log structure in codimension one on Y', for any birational model Y' of Y.…

Algebraic Geometry · Mathematics 2007-05-23 Florin Ambro

We complete the study of birational geometry of Fano fiber spaces $\pi\colon V\to {\mathbb P}^1$, the fiber of which is a Fano double hypersurface of index 1. For each family of these varieties we either prove birational rigidity or produce…

Algebraic Geometry · Mathematics 2015-06-26 Aleksandr V. Pukhlikov

We introduce a canonical strip hypothesis for Fano varieties. We show that the canonical strip hypothesis for a Fano variety implies that the zeros of the Hilbert polynomial of embedded Calabi--Yau and general type hypersurfaces are located…

Algebraic Geometry · Mathematics 2009-03-13 V. Golyshev

Let $\pi:X\rightarrow\mathbb{P}^n$ be a (holomorphic) Lagrangian fibration that is very general in the moduli space of Lagrangian fibrations. We conjecture that the singular fibres in codimension one must be semistable degenerations of…

Algebraic Geometry · Mathematics 2021-12-28 Justin Sawon

In this paper we prove a uniqueness theorem on generalized Kahler-Einstein metrics on Fano manifolds. Our result generalize the one shown by Berndtsson using the convexity properties of Bergman kernels. The same technics as well as that of…

Complex Variables · Mathematics 2013-01-16 Li Yi

We classify singular fibres over general points of the discriminant locus of projective complex Lagrangian fibrations on 4-dimensional holomorphic symplectic manifolds. The singular fibre F is the following either one: F is isomorphic to…

Algebraic Geometry · Mathematics 2007-05-23 Daisuke Matsushita

Filipazzi, Hacon and Svaldi proved that there are only finitely many topological types of elliptically fibered Calabi-Yau threefolds. We explore the implications of their results on the boundedness of the geometric quantities in the…

Algebraic Geometry · Mathematics 2023-07-28 Antonella Grassi

We prove the general diagram method theorem valid for the quite large class of 3-folds with Q-factorial singularities (see Basic Theorem 1.3.2 and also Theorem 2.2.6). This gives the generalization of our results about Fano 3-folds with…

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

Let $\pi:X\rightarrow Z$ be a Fano type fibration with $\dim X-\dim Z=d$ and let $(X,B)$ be an $\epsilon$-lc pair with $K_X+B\sim_{\RR} 0/Z$. The canonical bundle formula gives $(Z,B_Z+M_Z)$ where $B_Z$ is the discriminant divisor and $M_Z$…

Algebraic Geometry · Mathematics 2024-11-28 Bingyi Chen