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This work focuses on approximation and generation for the derived category of complexes with quasi-coherent cohomology on algebraic stacks. Our methods establish that approximation by compact objects descends along covers that are…

Algebraic Geometry · Mathematics 2025-05-01 Jack Hall , Alicia Lamarche , Pat Lank , Fei Peng

We give several related versions of global Grothendieck Duality for unbounded complexes on noetherian formal schemes. The proofs, based on a non-trivial adaptation of Deligne's method for the special case of ordinary schemes, are reasonably…

alg-geom · Mathematics 2008-02-03 Leovigildo Alonso , Ana Jeremias , Joseph Lipman

We investigate the properties of relative analogues of admissible Ind, Pro, and elementary Tate objects for pairs of exact categories, and give criteria for those categories to be abelian. A relative index map is introduced, and as an…

K-Theory and Homology · Mathematics 2015-11-19 Oliver Braunling , Michael Groechenig , Jesse Wolfson

We show that every quasi-compact and quasi-separated algebraic stack can be approximated by a noetherian algebraic stack. We give several applications such as eliminating noetherian hypotheses in the theory of good moduli spaces.

Algebraic Geometry · Mathematics 2023-11-16 David Rydh

A subgroup $H\leq G$ is said to be almost normal if every conjugate of $H$ is commensurable to $H$. If $H$ is almost normal, there is a well-defined quotient space $G/H$. We show that if a group $G$ has type $F_{n+1}$ and contains an almost…

Group Theory · Mathematics 2021-09-15 Alexander Margolis

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

The R-module functors that are essential for the development of the theory of the linear representations of an affine R-group are the quasi-coherent R-modules and the R-module schemes. The aim of this paper is to study when a quasi-coherent…

Commutative Algebra · Mathematics 2011-11-10 Amelia Álvarez Sánchez , Carlos Sancho de Salas , Pedro Sancho de Salas

We develop the theory of almost-holomorphic and quasimodular forms for orthogonal groups of a lattice of signature $(2,n)$ through orthogonal lowering and raising operators. The interactions with the regularized theta lift of Borcherds is a…

Algebraic Geometry · Mathematics 2025-05-15 Georg Oberdieck , Brandon Williams

We develop the theory of coregular sequences and codepth for modules that need not be finitely generated or artinian over a Noetherian ring. We use this theory to give a new version of a theorem of Hellus characterizing set-theoretic…

Commutative Algebra · Mathematics 2019-07-15 Robin Hartshorne , Claudia Polini

Noether's theorem, which connects continuous symmetries to exact conservation laws, remains one of the most fundamental principles in physics and dynamical systems. In this work, we draw a conceptual parallel between two paradigms: the…

Chaotic Dynamics · Physics 2026-03-24 Tim Zolkin , Sergei Nagaitsev , Ivan Morozov , Sergei Kladov

Given an algebraic stack $X$, one may compare the derived category of quasi-coherent sheaves on $X$ with the category of dg-modules over the dg-ring of functions on $X$. We study the analogous question in stable homotopy theory, for derived…

Algebraic Topology · Mathematics 2016-06-27 Akhil Mathew , Lennart Meier

Let $f \colon X \to Y$ be a morphism of concentrated schemes. We characterize $f$-perfect complexes $\mathcal{E}$ as those such that the functor $\mathcal{E} \otimes^{\mathbf{L}}_X \mathbf{L} f^*-$ preserves bounded complexes. We prove, as…

Algebraic Geometry · Mathematics 2023-09-15 Leovigildo Alonso , Ana Jeremias , Fernando Sancho

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 quasi-projective relation algebras and directed cylindric algebras are equivalent categorialy. We work out a Godels second incompleteness theorem for finite varibale fragments of first order logic. We show that distinct set…

Logic · Mathematics 2013-04-04 Tarek Sayed Ahmed

Let $\mathbb{X}$ be a semiseparated Noetherian scheme with a dualizing complex $D$. We lift some well-known triangulated equivalences associated with Grothendieck duality to Quillen equivalences of model categories. In the process we are…

Algebraic Topology · Mathematics 2021-09-08 Sergio Estrada , James Gillespie

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

In this article we continue our investigation of the Derived Equivalences over noetherian quasi-projective schemes $X$, over affine schemes $\spec{A}$. For integers $k\geq 0$, let $C{\mathbb M}^k(X)$ denote the category of coherent…

Commutative Algebra · Mathematics 2015-09-10 Satya Mandal

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

We display a symmetric monoidal equivalence between the stable $\infty$-category of filtered spectra, and quasi-coherent sheaves on $\mathbb{A}^1 / \mathbb{G}_m$, the quotient in the setting of spectral algebraic geometry, of the flat…

Algebraic Topology · Mathematics 2021-09-17 Tasos Moulinos

We construct a quasi-particle basis of the integrable highest weight module of highest weight $3\Lambda_0$ for the twisted affine Lie algebra of type $A_2^{(2)}$ in the principal realization. More specifically, by introducing the concept of…

Quantum Algebra · Mathematics 2026-03-25 Marijana Butorac , Slaven Kožić , Mirko Primc