Results 31 to 40 of about 1,068 (81)

Characteristic foliations — A survey

Bulletin of the London Mathematical Society, Volume 56, Issue 7, Page 2231-2249, July 2024.
Abstract This is a survey article, with essentially complete proofs, of a series of recent results concerning the geometry of the characteristic foliation on smooth divisors in compact hyperkähler manifolds, starting with work by Hwang–Viehweg, but also covering articles by Amerik–Campana and Abugaliev.
Fabrizio Anella, Daniel Huybrechts
wiley   +1 more source

Subquadratic harmonic functions on Calabi‐Yau manifolds with maximal volume growth

Communications on Pure and Applied Mathematics, Volume 77, Issue 6, Page 3080-3106, June 2024.
Abstract On a complete Calabi‐Yau manifold M$M$ with maximal volume growth, a harmonic function with subquadratic polynomial growth is the real part of a holomorphic function. This generalizes a result of Conlon‐Hein. We prove this result by proving a Liouville‐type theorem for harmonic 1‐forms, which follows from a new local L2$L^2$ estimate of the ...
Shih‐Kai Chiu
wiley   +1 more source

Gravitational instantons with quadratic volume growth

Journal of the London Mathematical Society, Volume 109, Issue 4, April 2024.
Abstract There are two known classes of gravitational instantons with quadratic volume growth at infinity, known as type ALG$\operatorname{ALG}$ and ALG∗$\operatorname{ALG}^*$. Gravitational instantons of type ALG$\operatorname{ALG}$ were previously classified by Chen–Chen.
Gao Chen, Jeff Viaclovsky
wiley   +1 more source

Closed 3‐forms in five dimensions and embedding problems

Journal of the London Mathematical Society, Volume 109, Issue 4, April 2024.
Abstract We consider the question if a five‐dimensional manifold can be embedded into a Calabi–Yau manifold of complex dimension 3 such that the real part of the holomorphic volume form induces a given closed 3‐form on the 5‐manifold. We define an open set of 3‐forms in dimension five which we call strongly pseudoconvex, and show that for closed ...
Simon Donaldson, Fabian Lehmann
wiley   +1 more source

Systems of symplectic forms on four-manifolds [PDF]

, 2012
We study almost Hermitian 4-manifolds with holonomy algebra, for the canonical Hermitian connection, of dimension at most one. We show how Riemannian 4-manifolds admitting five orthonormal symplectic forms fit therein and classify them. In this set-up we
Chiossi, SImon G., Nagy, Paul-Andi
core   +1 more source

Spin(7)-instantons, Cayley submanifolds, and Fueter sections

, 2016
We prove an existence theorem for Spin(7)-instantons, which are highly concentrated near a Cayley submanifold; thus giving a partial converse to Tian's foundational compactness theorem.
Walpuski, Thomas
core   +1 more source

Integrability of Einstein deformations and desingularizations

Communications on Pure and Applied Mathematics, Volume 77, Issue 1, Page 177-220, January 2024.
Abstract We study the question of the integrability of Einstein deformations and relate it to the question of the desingularization of Einstein metrics. Our main application is a negative answer to the long‐standing question of whether or not every Einstein 4‐orbifold (which is an Einstein metric space in a synthetic sense) is limit of smooth Einstein ...
Tristan Ozuch
wiley   +1 more source

One‐dimensional local families of complex K3 surfaces

Bulletin of the London Mathematical Society, Volume 56, Issue 1, Page 296-305, January 2024.
Abstract For any complex K3 surface X$X$, we construct a one‐dimensional deformation in which all integers ρ$\rho$ with 0⩽ρ⩽20$0 \leqslant \rho \leqslant 20$ occur as Picard numbers of some fibres. In contrast, we prove that the generic one‐dimensional local family of K3 surfaces admits only 0 and 1 as Picard numbers of the fibres.
Riccardo Carini, Francesco Viganò
wiley   +1 more source

Tensionless Strings and Supersymmetric Sigma Models: Aspects of the Target Space Geometry [PDF]

, 2006
In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models. The equivalent to a massless particle in string theory is a tensionless string.
Bredthauer, Andreas
core   +1 more source

Abundance for varieties with many differential forms

, 2018
We prove that the abundance conjecture holds on a variety $X$ with mild singularities if $X$ has many reflexive differential forms with coefficients in pluricanonical bundles, assuming the Minimal Model Program in lower dimensions.
Lazić, Vladimir, Peternell, Thomas
core   +1 more source