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We develop a theory of Hilbert $\widetilde{\C}$-modules by investigating their structural and functional analytic properties. Particular attention is given to finitely generated submodules, projection operators, representation theorems for…

Functional Analysis · Mathematics 2014-04-01 Claudia Garetto , Hans Vernaeve

We prove a vanishing theorem for one forms on the moduli stack of principally polarized abelian varieties of genus g>1 with level structure N over fields of characteristic p different from two. This is used to compute the Picard groups of…

Number Theory · Mathematics 2010-10-22 Rainer Weissauer

We provide a general method for constructing moduli stacks whose points are diagrams of vector bundles over a fixed base, indexed by a fixed simplicial set -- that is, quiver bundles of a fixed shape. We discuss some constraints on the base…

Algebraic Geometry · Mathematics 2025-02-18 Mahmud Azam , Steven Rayan

The aim of this paper is two--fold. We first strongly improve our previous main result Theorem 3.1 in Arxiv 1702.00918v3 12Feb2018 ("Brill-Noether loci of rank two vector bundles on a general $\nu$-gonal curve"), concerning classification…

Algebraic Geometry · Mathematics 2018-09-07 Youngook Choi , Flaminio Flamini , Seonja Kim

The goal is to verify the Hodge conjecture (and some related conjectures) for certain moduli spaces. It is shown that the (generalized) Hodge conjecture holds for the projective moduli spaces of vector bundles over an abelian or K3 surface…

Algebraic Geometry · Mathematics 2007-05-23 Donu Arapura

We introduce ``sheafification'' functors from categories of (lax monoidal) linear functors to categories of quasi-coherent sheaves (of algebras) of stacks. They generalize the homogeneous sheafification of graded modules for projective…

Algebraic Geometry · Mathematics 2020-10-27 Fabio Tonini

In a recent paper, G. Cz\'edli and E.\,T. Schmidt present a structure theorem for planar semimodular lattices. In this note, we present an alternative proof.

Rings and Algebras · Mathematics 2022-08-08 G. Grätzer

''Positive geometries'' are a class of semi-algebraic domains which admit a unique ''canonical form'': a logarithmic form whose residues match the boundary structure of the domain. The study of such geometries is motivated by recent…

Algebraic Geometry · Mathematics 2025-09-11 Francis Brown , Clément Dupont

We show how natural functors from the category of coherent sheaves on a projective scheme to categories of Kronecker modules can be used to construct moduli spaces of semistable sheaves. This construction simplifies or clarifies technical…

Algebraic Geometry · Mathematics 2009-11-11 Luis Álvarez-Cónsul , Alastair King

We introduce moduli spaces of quasi-admissible hyperelliptic covers with at worst A and D singularities. The stability conditions for these moduli spaces depend on two parameters describing allowable singularities. By varying these…

Algebraic Geometry · Mathematics 2010-12-03 Maksym Fedorchuk

A stable pair on a projective variety consists of a sheaf and a global section subject to stability conditions parameterized by rational polynomials. We will show that for a smooth projective threefold and a class of a rank 2 sheaf, there…

Algebraic Geometry · Mathematics 2026-01-12 Marcos Jardim , Dapeng Mu

Let S be a connected scheme smooth and of finite type over the field of complex numbers. To every 1-motive over S, Andr\'e associated the enriched Hodge realization given by a torsion-free, graded-polarizable and admissible variation of…

Algebraic Geometry · Mathematics 2026-05-28 Cristiana Bertolin

We investigate a semi-continuity property for stability conditions for sheaves that is important for the problem of variation of the moduli spaces as the stability condition changes. We place this in the context of a notion of stability…

Algebraic Geometry · Mathematics 2019-06-28 Daniel Greb , Julius Ross , Matei Toma

In this note, we aim to prove the finite semi-algebraic chamber decomposition theorem for K-semi(poly)stability under the assumption of the log boundedness of K-semistable degenerations. This boundedness assumption is naturally arising from…

Algebraic Geometry · Mathematics 2025-09-22 Chuyu Zhou

We show that very general hypersurfaces in odd-dimensional simplicial projective toric varieties verifying a certain combinatorial property satisfy the Hodge conjecture (these include projective spaces). This gives a connection between the…

Algebraic Geometry · Mathematics 2021-10-12 Ugo Bruzzo , Antonella Grassi

We review a proof of the well know result stating that moduli spaces of stable sheaves with fixed Chern character on a polarized $K3$ surface are deformations of a hyperk\"ahler variety of Type $K3^{[n]}$ (if a suitable numerical hypothesis…

Algebraic Geometry · Mathematics 2021-09-16 Kieran G. O'Grady

K-polystability is, on the one hand, conjecturally equivalent to the existence of certain canonical K\"ahler metrics on polarised varieties, and, on the other hand, conjecturally gives the correct notion to form moduli. We introduce a…

Algebraic Geometry · Mathematics 2021-09-15 Ruadhaí Dervan , Lars Martin Sektnan

We reformulate the construction of Kontsevich's completion and use Lawson homology to define many new motivic invariants. We show that the dimensions of subspaces generated by algebraic cycles of the cohomology groups of two $K$-equivalent…

Algebraic Geometry · Mathematics 2008-07-10 Jyh-Haur Teh

We provide supplements and open problems related to structure theorems for maximal rationally connected fibrations of certain positively curved projective varieties, including smooth projective varieties with semi-positive holomorphic…

Algebraic Geometry · Mathematics 2022-11-18 Shin-ichi Matsumura

We introduce a notion of stable spherical variety which includes the spherical varieties under a reductive group $G$ and their flat equivariant degenerations. Given any projective space $\bP$ where $G$ acts linearly, we construct a moduli…

Algebraic Geometry · Mathematics 2007-05-23 Valery Alexeev , Michel Brion