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Related papers: Lagrangian fibrations on hyperk\"ahler fourfolds

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Let $X$ be a hyperk\"ahler manifold, and let $A$ be a nef and big divisor on $X$. We show that the fixed part of the linear system $|A|$ is reduced and as a consequence $|2A|$ is mobile. If $X$ has dimension four we also show that if the…

Algebraic Geometry · Mathematics 2025-11-17 Daniele Agostini , Andreas Höring

We show that Lagrangian submanifolds in six-dimensional nearly K\"ahler (non K\"ahler) manifolds and in twistor spaces $Z\sp{4n+2}$ over quaternionic K\"ahler manifolds $Q\sp{4n}$ are minimal. Moreover, we will prove that any Lagrangian…

Differential Geometry · Mathematics 2009-04-24 Lars Schäfer , Knut Smoczyk

We extend the Abreu-Guillemin theory of invariant K\"ahler metrics from toric symplectic manifolds to any symplectic manifold admitting a toric action of a symplectic torus bundle. We show that these are precisely the symplectic manifolds…

Differential Geometry · Mathematics 2026-04-16 Rui Loja Fernandes , Maarten Mol

We develop the foundation of the complex symplectic geometry of Lagrangian subvarieties in a hyperkahler manifold. We establish a characterization, a Chern number inequality, topological and geometrical properties of Lagrangian…

Symplectic Geometry · Mathematics 2016-09-07 Naichung Conan Leung

A tractable definition of the homogeneous nearly K\"ahler structure on $\mathbb{C}P^3$ is given via the Hopf fibration, facilitating explicit computations and analysis. The description extends to all homogeneous metrics on $\mathbb{C}P^3$,…

Differential Geometry · Mathematics 2026-01-27 Michaël Liefsoens , Joeri Van der Veken

We review the theory of Lagrangian fibrations of hyperk\"ahler manifolds as initiated by Matsushita. We also discuss more recent work of Shen-Yin and Harder-Li-Shen-Yin. Occasionally, we give alternative arguments and complement the…

Algebraic Geometry · Mathematics 2022-02-02 Daniel Huybrechts , Mirko Mauri

In this note we build on the arguments of van Geemen and Voisin to prove a conjecture of Matsushita that a Lagrangian fibration of an irreducible hyperk\"ahler manifold is either isotrivial or of maximal variation. We also complete a…

Algebraic Geometry · Mathematics 2022-10-03 Benjamin Bakker

We shall show how to decompose, by functorial and canonical fibrations, arbitrary $n$-dimensional complex projective {Although the geometric results apply to compact K\" ahler manifolds without change, we consider here for simplicity this…

Algebraic Geometry · Mathematics 2010-01-22 Frederic Campana

In this paper a bijective correspondence between superminimal surfaces of an oriented Riemannian $4$-manifold and particular Lagrangian submanifolds of the twistor space over the $4$-manifold is proven. More explicitly, for every…

Differential Geometry · Mathematics 2020-01-22 Reinier Storm

We study O'Grady examples of irreducible symplectic varieties: we establish that both of them can be deformed into lagrangian fibrations. We analyse in detail the topology of the six dimensional example: in particular we compute its Euler…

Algebraic Geometry · Mathematics 2007-05-23 Antonio Rapagnetta

Given a Lagrangian fibration $\pi : X \to \mathbb{P}^n$ of a compact hyper-K\"ahler manifold of $\text{K3}^{[n]}$, $\text{Kum}_n$, $\text{OG10}$ or $\text{OG6}$-type, we construct a natural compactification of its dual torus fibration.…

Algebraic Geometry · Mathematics 2022-08-09 Yoon-Joo Kim

We consider the question whether a real threefold X fibred into quadric surfaces over the real projective line is stably rational (over R) if the topological space X(R) is connected. We give a counterexample. When all geometric fibres are…

Algebraic Geometry · Mathematics 2026-02-11 Jean-Louis Colliot-Thélène , Alena Pirutka

Suppose that f is a projective birational morphism with at most one-dimensional fibres between d-dimensional varieties X and Y, satisfying ${\bf R}f_* \mathcal{O}_X = \mathcal{O}_Y$. Consider the locus L in Y over which f is not an…

Algebraic Geometry · Mathematics 2018-10-30 Will Donovan , Michael Wemyss

Let $M$ be a compact, holomorphic symplectic Kaehler manifold, and $L$ a non-trivial line bundle admitting a metric of semi-positive curvature. We show that some power of $L$ is effective. This result is related to the hyperkaehler SYZ…

Algebraic Geometry · Mathematics 2010-04-07 Misha Verbitsky

The purpose of this note is to establish the following theorem: Let N be a Kahler manifold, L be a compact oriented immersed minimal Lagrangian submanifold in N and V be a holomorphic vector field in a neighbourhood of L in N. Let div(V) be…

Differential Geometry · Mathematics 2007-05-23 Edward Goldstein

We generalize Voisin's theorem on deformations of pairs of a symplectic manifold and a Lagrangian submanifold to the case of Lagrangian normal crossing subvarieties. Partial results are obtained for arbitrary Lagrangian subvarieties. We…

Algebraic Geometry · Mathematics 2015-04-27 Christian Lehn

In 1996, Strominger, Yau and Zaslow made a conjecture about the geometric relationship between two mirror Calabi-Yau manifolds. Roughly put, if X and Y are a mirror pair of such manifolds, then X should possess a special Lagrangian torus…

alg-geom · Mathematics 2007-05-23 Mark Gross

We prove that irreducible Calabi-Yau varieties of a fixed dimension, admitting a fibration by abelian varieties or primitive symplectic varieties of a fixed analytic deformation class, are birationally bounded. We prove that there are only…

Algebraic Geometry · Mathematics 2025-07-02 Philip Engel , Stefano Filipazzi , François Greer , Mirko Mauri , Roberto Svaldi

We prove some results on the fibers and images of rational maps from a hyper-K\"ahler manifold. We study in particular the minimal genus of fibers of a fibration into curves. The last section of this paper is devoted to the study of the…

Algebraic Geometry · Mathematics 2022-08-23 Claire Voisin

We define topological invariants of regular Lagrangian fibrations using the integral affine structure on the base space and we show that these coincide with the classes known in the literature. We also classify all symplectic types of…

Symplectic Geometry · Mathematics 2015-05-14 D. Sepe