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We introduce an "extended locus of Hodge classes" that also takes into account integral classes that become Hodge classes "in the limit". More precisely, given a polarized variation of integral Hodge structure of weight zero on a…

Algebraic Geometry · Mathematics 2014-01-29 Christian Schnell

We use tools of mathematical logic to analyse the notion of a path on an complex algebraic variety, and are led to formulate a "rigidity" property of fundamental groups specific to algebraic varieties, as well as to define a bona fide…

Algebraic Geometry · Mathematics 2009-05-12 Misha Gavrilovich

In this paper we give a characterization of the height of K3 surfaces in positive characteristic. This enables us to calculate the cycle classes of the loci in families of K3 surfaces where the height is at least h. The formulas for such…

Algebraic Geometry · Mathematics 2007-05-23 G. van der Geer , T. Katsura

We study a notion of total acyclicity for complexes of flat sheaves over a scheme. It is Zariski-local - i.e. it can be verified on any open affine covering of the scheme - and it agrees, in their setting, with the notion studied by Murfet…

Commutative Algebra · Mathematics 2016-06-24 Lars Winther Christensen , Sergio Estrada , Alina Iacob

Let $k$ be a field of characteristic zero and I an ideal defining an arrangement of linear subspaces in the affine space $A^n_k$. We compute the D-module theoretic characteristic cycle of the local cohomology modules $H^r_I(k[x_1,...,x_n])$…

Algebraic Geometry · Mathematics 2007-05-23 Josep Alvarez Montaner , Ricardo Garcia Lopez , Santiago Zarzuela

We develop and collect techniques for determining Hochschild cohomology of skew group algebras S(V)#G and apply our results to graded Hecke algebras. We discuss the explicit computation of certain types of invariants under centralizer…

Rings and Algebras · Mathematics 2007-05-23 Anne V. Shepler , Sarah Witherspoon

Given a smooth projective 3-fold Y, with $H^{3,0}(Y)=0$, the Abel-Jacobi map induces a morphism from each smooth variety parameterizing 1-cycles in Y to the intermediate Jacobian J(Y). We study in this paper the existence of families of…

Algebraic Geometry · Mathematics 2011-08-16 Claire Voisin

Given a smooth projective 3-fold Y, with $H^{3,0}(Y)=0$, the Abel-Jacobi map induces a morphism from each smooth variety parameterizing 1-cycles in Y to the intermediate Jacobian J(Y). We study in this paper the existence of families of…

Algebraic Geometry · Mathematics 2015-08-14 Claire Voisin

Let $A$ be a non-isotrivial almost ordinary abelian surface with possibly bad reductions over a global function field of odd characteristic $p$. Suppose $\Delta$ is an infinite set of positive integers, such that…

Number Theory · Mathematics 2025-04-10 Ruofan Jiang

We compute the subgroup of the monodromy group of a generalized Kummer variety associated to equivalences of derived categories of abelian surfaces. The result was previously announced in arXiv:1201.0031. Mongardi showed that the subgroup…

Algebraic Geometry · Mathematics 2024-10-29 Eyal Markman

We explicitly describe cycle-class maps c_H from motivic cohomology to absolute Hodge cohomology, for smooth quasi-projective and (some) proper singular varieties, and compute special cases of the latter. For smooth projective varieties, we…

Algebraic Geometry · Mathematics 2009-11-11 Matt Kerr , James D. Lewis

This article studies the symplectic cohomology of affine algebraic surfaces that admit a compactification by a normal crossings anticanonical divisor. Using a toroidal structure near the compactification divisor, we describe the complex…

Symplectic Geometry · Mathematics 2019-12-11 James Pascaleff

Let $K$ be an unramified $p$-adic local field and let $W$ be the ring of integers of $K$. Let $(X,S)/W$ be a smooth proper scheme together with a simple normal crossings divisor and fix positive integers $r$ and $f$. We show that the set of…

Algebraic Geometry · Mathematics 2020-09-02 Raju Krishnamoorthy , Jinbang Yang , Kang Zuo

In this paper, we study the combinatorics of a subcomplex of the Bloch-Kriz cycle complex [4] used to construct the category of mixed Tate motives. The algebraic cycles we consider properly contain the subalgebra of cycles that correspond…

Algebraic Geometry · Mathematics 2018-03-16 Susama Agarwala , Owen Patashnick

This paper explores the cohomology of linear cycle sets, focusing on extensions of a specific linear cycle set H by an abelian group I. We derive explicit formulas for the second cohomology group, which classifies these extensions, and…

Group Theory · Mathematics 2025-01-16 Jorge Guccione , Juan José Guccione , Christian Valqui

We study the algebraic exceptional set for surfaces (S,B) of log general type, when B has at least three irreducible components; we prove that in most cases it is finite or empty.

Algebraic Geometry · Mathematics 2026-03-27 Lucia Caporaso , Amos Turchet

We prove that the universal cover of a normal complex algebraic variety admitting a faithful complex representation of its fundamental group is an analytic Zariski open subset of a holomorphically convex complex space. This is a non-proper…

Algebraic Geometry · Mathematics 2024-08-30 Benjamin Bakker , Yohan Brunebarbe , Jacob Tsimerman

Using the classical universal coefficient theorem of Rosenberg-Schochet, we prove a simple classification of all localizing subcategories of the Bootstrap category of separable complex C*-algebras. Namely, they are in bijective…

K-Theory and Homology · Mathematics 2012-02-21 Ivo Dell'Ambrogio

In this short note, we simply collect some known results about representing algebraic cycles by various kind of "nice" (e.g. smooth, local complete intersection, products of local complete intersection) algebraic cycles, up to rational…

Algebraic Geometry · Mathematics 2016-12-15 Marco Maggesi , Gabriele Vezzosi

For W a finite (2-)reflection group and B its (generalized) braid group, we determine the Zariski closure of the image of B inside the corresponding Iwahori-Hecke algebra. The Lie algebra of this closure is reductive and generated in the…

Representation Theory · Mathematics 2009-11-11 Ivan Marin