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This paper introduces an abelian category of logarithmic coherent sheaves that arranges coherent sheaves across all expansions and root stacks of a simple normal crossing degeneration. Formally, logarithmic coherent sheaves are coherent…

Algebraic Geometry · Mathematics 2026-04-08 Hannah Dell , Xianyu Hu , Patrick Kennedy-Hunt , Kabeer Manali Rahul , Maximilian Schimpf

We show that for quasi-compact quasi-separated schemes of finite dimension, the constructibility condition in real \'etale cohomology agrees with a notion of constructibility arising naturally from topology. As application we prove that the…

Algebraic Geometry · Mathematics 2022-01-04 Fangzhou Jin

We introduce stacks classifying \'etale germs of pointed n-dimensional varieties. We show that quasi-coherent sheaves on these stacks are universal D- and O-modules. We state and prove a relative version of Artin's approximation theorem,…

Algebraic Geometry · Mathematics 2017-02-27 Emily Cliff

A geometric stack is a quasi-compact and semi-separated algebraic stack. We prove that the quasi-coherent sheaves on the small flat topology, Cartesian presheaves on the underlying category, and comodules over a Hopf algebroid associated to…

Algebraic Geometry · Mathematics 2017-04-27 Leovigildo Alonso , Ana Jeremias , Marta Perez , Maria J. Vale

We show a few basic results about moduli spaces of semistable modules over Lie algebroids. The first result shows that such moduli spaces exist for relative projective morphisms of noetherian schemes, removing some earlier constraints. The…

Algebraic Geometry · Mathematics 2022-11-15 Adrian Langer

For a noetherian scheme that has an ample family of invertible sheaves, we prove that direct products in the category of quasi-coherent sheaves are not exact unless the scheme is affine. This result can especially be applied to all…

Category Theory · Mathematics 2020-06-23 Ryo Kanda

Let $k$ be a perfect field of characteristic $p > 0$. For a strictly semi-stable scheme over $k[[t]]$, we construct the weight spectral sequence in $p$-adic cohomology using the theory of arithmetic $\mathcal{D}$-modules, whose $E_1$ terms…

Algebraic Geometry · Mathematics 2026-04-16 Yuanmin Liu

We identify a class of "quasi-compact semi-separated" (qcss) twisted presheaves of algebras A for which well-behaved Grothendieck abelian categories of quasi-coherent modules Qch(A) are defined. This class is stable under algebraic…

Algebraic Geometry · Mathematics 2015-09-14 Hoang Dinh Van , Liyu Liu , Wendy Lowen

The moduli spaces of stable sheaves on projective schemes admit certain gluing data of Kapranov's NC structures, which we call quasi NC structures. The formal completion of the quasi NC structure at a closed point coincides with the…

Algebraic Geometry · Mathematics 2015-11-03 Yukinobu Toda

We develop a theory of derived rigid spaces and quasi-coherent sheaves and analytic "stratifications" on them. Amongst other things, we obtain a six-functor formalism for these quasi-coherent sheaves and analytic stratifications. We provide…

Number Theory · Mathematics 2025-09-22 Arun Soor

We classify finitely generated modules over a class of algebras introduced in the authors' Ph.D thesis, called complete gentle algebras. These rings generalise the finite-dimensional gentle algebras introduced by Assem and Skowro\'{n}ski,…

Representation Theory · Mathematics 2021-07-21 Raphael Bennett-Tennenhaus

A general notion of a quasi-finite algebra is introduced as an algebra graded by the set of all integers equipped with topologies on the homogeneous subspaces satisfying certain properties. An analogue of the regular bimodule is introduced…

Quantum Algebra · Mathematics 2007-05-23 Atsushi Matsuo , Kiyokazu Nagatomo , Akihiro Tsuchiya

In this paper we prove a general convergence theorem for almost-additive set functions on unimodular, amenable groups. These mappings take their values in some Banach space. By extending the theory of epsilon-quasi tiling techniques, we set…

Dynamical Systems · Mathematics 2017-10-26 Felix Pogorzelski

Quasi-projective dimension of modules over associative rings is generalized in this paper to the one of complexes of modules. Basic properties of this dimension are established, including a comparison result with projective dimension and a…

Rings and Algebras · Mathematics 2026-04-13 Hongxing Chen , Jiangsheng Hu , Xiaoyan Yang

We show that a purely algebraic structure, a two-dimensional scattering diagram, describes a large part of the wall-crossing behavior of moduli spaces of Bridgeland semistable objects in the derived category of coherent sheaves on…

Algebraic Geometry · Mathematics 2025-09-30 Pierrick Bousseau

Raynaud--Gruson characterized flat and pure morphisms between affine schemes in terms of projective modules. We give a similar characterization for non-affine morphisms. As an application, we show that every quasi-coherent sheaf is the…

Algebraic Geometry · Mathematics 2016-09-01 David Rydh

Let $\varphi\colon R \rightarrow A$ be a finite ring homomorphism, where $R$ is a two-sided Noetherian ring, and let $M$ be a finitely generated left $A$-module. Under suitable homological conditions on $A$ over $R$, we establish a close…

Representation Theory · Mathematics 2026-04-27 Jian Liu

In a previous paper the authors constructed a class of quasi-Hopf algebras $D^{\omega}(G, A)$ associated to a finite group $G$, generalizing the twisted quantum double construction. We gave necessary and sufficient conditions, cohomological…

Quantum Algebra · Mathematics 2023-02-09 Geoffrey Mason , Siu-Hung Ng

A quasi-coherent ringed scheme is a pair (X,A), where X is a scheme, and A is a noncommutative quasi-coherent O_X-ring. We introduce dualizing complexes over quasi-coherent ringed schemes and study their properties. For a separated…

Algebraic Geometry · Mathematics 2007-05-23 Amnon Yekutieli , James J. Zhang

We start the general structure theory of not necessarily semisimple finite tensor categories, generalizing the results in the semisimple case (i.e. for fusion categories), obtained recently in our joint work with D.Nikshych. In particular,…

Quantum Algebra · Mathematics 2007-05-23 Pavel Etingof , Viktor Ostrik