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Related papers: On the construction of Weakly Ulrich bundles

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A Riemannian manifold $(M,g)$ is called \emph{weakly Einstein} if the tensor $R_{iabc}R_{j}^{~~abc}$ is a scalar multiple of the metric tensor $g_{ij}$. We give a complete classification of weakly Einstein hypersurfaces in the spaces of…

Differential Geometry · Mathematics 2024-12-18 Jihun Kim , Yuri Nikolayevsky , JeongHyeong Park

In this paper we characterize smooth complex projective varieties that admit a quadric bundle structure on some dense open subset in terms of the geometry of certain families of rational curves.

Algebraic Geometry · Mathematics 2008-11-07 Carolina Araujo

Context. A porous and/or fractal description can generally be applied where particles have undergone coagulation into aggregates. Aims. To characterise finite-sized, porous and fractal particles and to understand the possible limitations of…

Disordered Systems and Neural Networks · Physics 2015-11-09 A. P. Jones

We derive a general formula for the Euler characteristic of a fibration of projective hypersurfaces in terms of invariants of an arbitrary base variety. When the general fiber is an elliptic curve, such formulas have appeared in the physics…

Algebraic Geometry · Mathematics 2019-05-10 James Fullwood , Martin Helmer

In this article we develop a new way of systematically constructing infinitely many families of smooth subvarieties $X$ of any given dimension $m$, $m \geq 3$, and any given codimension in $\mathbb P^N$, embedded by complete subcanonical…

Algebraic Geometry · Mathematics 2022-12-20 Purnaprajna Bangere , Francisco Javier Gallego , Jayan Mukherjee , Debaditya Raychaudhury

We study aspects of the A^1-homotopy classification problem in dimensions >= 3 and, to this end, we investigate the problem of computing A^1-homotopy groups of some A^1-connected smooth varieties of dimension >=. Using these computations,…

Algebraic Geometry · Mathematics 2012-12-21 Aravind Asok

In this paper we contribute to the construction of families of arithmetically Cohen-Macaulay (aCM) indecomposable vector bundles on a wide range of polarized surfaces $(X,\Oo_X(1))$ for $\Oo_X(1)$ an ample line bundle. In many cases, we…

Algebraic Geometry · Mathematics 2018-07-25 Edoardo Ballico , Sukmoon Huh , Joan Pons-Llopis

In this paper we continue our study of the Frobenius instability locus in the coarse moduli space of semi-stable vector bundles of rank $r$ and degree $0$ over a smooth projective curve defined over an algebraically closed field of…

Algebraic Geometry · Mathematics 2024-10-14 Kirti Joshi , Christian Pauly

De Concini-Procesi introduced varieties known as wonderful compactifications, which are smooth projective compactifications of semisimple adjoint groups $G$. We study the Frobenius pushforwards of invertible sheaves on the wonderful…

Algebraic Geometry · Mathematics 2022-09-07 Merrick Cai , Vasily Krylov

The thesis studies Frobenius-type theorems in non-smooth settings. We extend the definition of involutivity to non-Lipschitz subbundles using generalized functions. We prove the real Frobenius Theorem with sharp regularity on log-Lipschitz…

Classical Analysis and ODEs · Mathematics 2022-10-18 Liding Yao

In this paper, we prove the existence of an Enriques surface with a polarization of degree four with an Ulrich bundle of rank one. As a consequence, we prove that general polarized Enriques surfaces of degree four, with the same numerical…

Algebraic Geometry · Mathematics 2024-01-17 Marian Aprodu , Yeongrak Kim

Given a projective variety $X$ and a very ample line bundle $\mathcal{L}$ on $X$, we classify for which $X$ and $\mathcal{L}$ the twisted syzygies and twisted dual syzygies bundles are Ulrich with respect to the polarizations…

Algebraic Geometry · Mathematics 2026-01-08 H. Torres López , Alexis G. Zamora

We construct an explicit K3 surface over the field of rational numbers that has geometric Picard rank one, and for which there is a transcendental Brauer-Manin obstruction to weak approximation. To do so, we exploit the relationship between…

Algebraic Geometry · Mathematics 2015-03-17 Brendan Hassett , Anthony Várilly-Alvarado , Patrick Varilly

In 1981 J. Wahl described smoothings of surface quotient singularities with no vanishing cycles. Given a smoothing of a projective surface X of this type, we construct an associated exceptional vector bundle on the nearby fiber Y in the…

Algebraic Geometry · Mathematics 2019-12-19 Paul Hacking

We prove that quasi-projective base spaces of smooth families of minimal varieties of general type with maximal variation do not admit Zariski dense entire curves. We deduce the fact that moduli stacks of polarized varieties of this sort…

Algebraic Geometry · Mathematics 2019-12-11 Mihnea Popa , Behrouz Taji , Lei Wu

We partially extend to hyperk\"ahler fourfolds of Kummer type the results that we have proved regarding stable rigid vector bundles on hyperk\"ahler (HK) varieties of type $K3^{[n]}$. Let $(M,h)$ be a general polarized HK fourfold of Kummer…

Algebraic Geometry · Mathematics 2026-05-27 Kieran G. O'Grady

This paper review one construction of Frobenius manifolds (and slightly weaker structures). It splits it into several steps and discusses the freedom and the constraints in these steps. The steps pass through holomorphic bundles with…

Differential Geometry · Mathematics 2019-12-10 Liana David , Claus Hertling

We show that a hyperbolic three-manifold $M$ containing a closed minimal surface with principal curvatures in $[-1,1]$ also contains nearby (non-minimal) surfaces with principal curvatures in $(-1,1)$. When $M$ is complete and homeomorphic…

Differential Geometry · Mathematics 2025-01-22 Manh-Tien Nguyen , Jean-Marc Schlenker , Andrea Seppi

We establish a new universal relation between the Lie bracket and $\circ$-multiplication of tangent fields on any Frobenius (super)manifold. We use this identity in order to introduce the notion of ``weak Frobenius manifold'' which does not…

Quantum Algebra · Mathematics 2007-05-23 Claus Hertling , Yuri Manin

First, we show that a warped product of a line and a fiber manifold is weakly conformally flat and quasi Einstein if and only if the fiber is Einstein. Next, we characterize and classify contact (in particular, $K$-contact) Riemannian…

Differential Geometry · Mathematics 2022-12-02 Ramesh Sharma