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Related papers: Hodge sheaves underlying flat projective families

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Fix a smooth projective family of curves $C \to S$ and a split reductive group scheme $G$ over a Noetherian base scheme $S$. For any (possibly nonreduced) fixed relative Cartier divisor $D$, we provide a treatment of the moduli of…

Algebraic Geometry · Mathematics 2025-04-02 Andres Fernandez Herrero , Siqing Zhang

The sl_2-triples play a fundamental role for the structure theory of Lie algebras, and representation theory in general. Here we investigate sl_2-triples of global vector fields on schemes X in positive characteristics p>0, and develop a…

Algebraic Geometry · Mathematics 2026-01-08 Stefan Schröer , Nikolaos Tziolas

Considering the so-called Simpson system on smooth projective varieties, defined over an algebraically closed field of characteristic 0, whose canonical bundle is ample, I give another proof the stability of this Higgs bundle, from which…

Algebraic Geometry · Mathematics 2025-10-07 Armando Capasso

I consider the class of surfaces $X$ over algebraically closed fields with numerical invariants given in the title. In characteristic zero, this class contains fake projective planes which were introduced by David Mumford. I prove that in…

Algebraic Geometry · Mathematics 2025-08-19 Kirti Joshi

Let G be an infinitesimal group scheme of finite height r and V(G) the scheme which represents 1-parameter subgroups of G. We consider sheaves over the projectivization P(G) of V(G) constructed from a G-module M. We show that if P(G) is…

Representation Theory · Mathematics 2015-04-01 Jim Stark

We propose a geometric and categorical approach to the Hodge Conjecture for all smooth projective complex varieties. By embedding any such variety into a flat family with general fibers smooth complete intersections, we prove the conjecture…

Algebraic Geometry · Mathematics 2025-08-15 Karim Mansour

For any free oriented Borel-Moore homology theory $A$, we construct an associative product on the $A$-theory of the stack of Higgs torsion sheaves over a projective curve $C$. We show that the resulting algebra $A\mathbf{Ha}_C^0$ admits a…

Representation Theory · Mathematics 2023-11-02 Alexandre Minets

A co-Higgs sheaf is a pair of a torsion-free coherent sheaf $\mathcal{E}$ and a global section of $\mathcal{E}nd(\mathcal{E})\otimes T_X$ with $T_X$ the tangent bundle. We construct $2$-nilpotent co-Higgs sheaves of rank two for some…

Algebraic Geometry · Mathematics 2017-07-28 Edoardo Ballico , Sukmoon Huh

We show that there exists a fine moduli space for torsion-free sheaves on a projective surface, which have a "good framing" on a big and nef divisor. This moduli space is a quasi-projective scheme. This is accomplished by showing that such…

Algebraic Geometry · Mathematics 2011-07-19 Ugo Bruzzo , Dimitri Markushevich

Let M be a projective fine moduli space of stable sheaves on a smooth projective variety X with a universal family E. We prove that in four examples, E can be realized as a complete flat family of stable sheaves on M parametrized by X,…

Algebraic Geometry · Mathematics 2020-06-12 Fabian Reede , Ziyu Zhang

We show that the dualizing sheaves of reduced simple normal crossings pairs have a canonical weight filtration in a compatible way with the one on the corresponding mixed Hodge modules by calculating the extension classes between the…

Algebraic Geometry · Mathematics 2013-06-25 Osamu Fujino , Taro Fujisawa , Morihiko Saito

We prove that any flat family $(\mathcal{ F}_u)_{u\in U}$ of rank 2 torsion-free sheaves on a Gauduchon surface defines a continuous map on the semi-stable locus $U^{\mathrm {ss}}:=\{u\in U \ |\ \mathcal{ F}_u\hbox{ is slope semi-stable}\}$…

Complex Variables · Mathematics 2017-11-01 Nicholas Buchdahl , Andrei Teleman , Matei Toma

The goal of this paper is to first define a Hodge theoretic fundamental group for smooth connected complex algebraic varieties and then prove and study a right exact sequence of Hodge theoretic fundamental groups associated to a smooth…

Algebraic Geometry · Mathematics 2025-10-22 Simon Shuofeng Xu

Cohomology of a compatible family of Lie algebroids defined on a family of transverse manifolds is defined. A sheaf of differential forms on a compatible family of Lie algebroids defined over regular open subsets of a simplicial complex is…

Algebraic Topology · Mathematics 2018-02-20 Jose R. Oliveira

Recently, many authors have embraced the study of certain properties of modules such as projectivity, injectivity and flatness from an alternative point of view. This way, Durgun has introduced absolutely pure domains of modules as a mean…

Algebraic Geometry · Mathematics 2024-11-15 Soumia Mamdouhi

Given a complex affine hypersurface with isolated singularity determined by a homogeneous polynomial, we identify the noncommutative Hodge structure on the periodic cyclic homology of its singularity category with the classical Hodge…

Algebraic Geometry · Mathematics 2025-08-19 Michael K. Brown , Mark E. Walker

We give a Hodge-theoretic proof of Hwang's theorem, which says that if the base of a Lagrangian fibration of an irreducible holomorphic symplectic manifold is smooth, it must be projective space.

Algebraic Geometry · Mathematics 2023-11-16 Benjamin Bakker , Christian Schnell

We define a notion of total acyclicity for complexes of flat quasi-coherent sheaves over a semi-separated noetherian scheme, generalising complete flat resolutions over a ring. By studying these complexes as objects of the pure derived…

Algebraic Geometry · Mathematics 2009-02-19 Daniel Murfet , Shokrollah Salarian

We show that a Hodge class of a complex smooth projective hypersurface is an analytic logarithmic De Rham class. On the other hand we show that for a complex smooth projective variety an analytic logarithmic De Rham class of of type $(d,d)$…

Algebraic Geometry · Mathematics 2025-10-17 Johann Bouali

A framed symplectic sheaf on a smooth projective surface $X$ is a torsion-free sheaf $E$ together with a trivialization on a divisor $D\subseteq X$ and a morphism $\Lambda^{2}E\rightarrow\mathcal{O}_{X}$ satisfying some additional…

Algebraic Geometry · Mathematics 2016-04-29 Jacopo Scalise