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For a finite abelian group $A$, we determine the Balmer spectrum of $\mathrm{Sp}_A^{\omega}$, the compact objects in genuine $A$-spectra. This generalizes the case $A=\mathbb{Z}/p\mathbb{Z}$ due to Balmer and Sanders \cite{Balmer-Sanders},…

Algebraic Topology · Mathematics 2023-07-19 Tobias Barthel , Markus Hausmann , Niko Naumann , Thomas Nikolaus , Justin Noel , Nathaniel Stapleton

Complex braid groups are the natural generalizations of braid groups associated to arbitrary (finite) complex reflection groups. We investigate several methods for computing the homology of these groups. In particular, we get the Poincar\'e…

Algebraic Topology · Mathematics 2010-11-22 Filippo Callegaro , Ivan Marin

We determine the Balmer spectrum of dualisable objects in the stable module category for $\mathrm{H}_1\mathfrak{F}$ groups of type $\mathrm{FP}_{\infty}$ and show that the telescope conjecture holds for these categories. We also determine…

Representation Theory · Mathematics 2025-04-24 Gregory Kendall

We prove that for any finite-dimensional differential graded algebra with separable semisimple part the category of perfect modules is equivalent to a full subcategory of the category of perfect complexes on a smooth projective scheme with…

Algebraic Geometry · Mathematics 2020-03-18 Dmitri Orlov

The results of the paper concern the topological structure of complete riemannian manifolds with cyclic holonomy groups and low-dimensional orientable complete flat manifolds. We also discuss related results such as the affine…

Differential Geometry · Mathematics 2007-05-23 M. Sadowski

This work studies $t$-structures for the derived category of quasi-coherent sheaves on a quasi-compact quasi-separated algebraic stack. Specifically, using Thomason filtrations, we classify those $t$-structures which are generated by…

Algebraic Geometry · Mathematics 2025-07-04 Pat Lank

We investigate the profinite completions of a certain family of groups acting on trees. It turns out that for some of the groups considered, the completions coincide with the closures of the groups in the full group of tree automorphisms.…

Group Theory · Mathematics 2007-05-23 Ekaterina Pervova

The complexity of an action of a reductive algebraic group G on an algebraic variety X is the codimension of a generic B-orbit in X, where B is a Borel subgroup of G. We classify affine homogeneous spaces G/H of complexity one. These…

Algebraic Geometry · Mathematics 2015-06-26 Ivan V. Arzhantsev , Olga V. Chuvashova

This work concerns finite free complexes over commutative noetherian rings, in particular over group algebras of elementary abelian groups. The main contribution is the construction of complexes such that the total rank of their underlying…

Commutative Algebra · Mathematics 2018-05-11 Srikanth B. Iyengar , Mark E. Walker

For any compactly generated triangulated category we introduce two topological spaces, the shift-spectrum and the shift-homological spectrum. We use them to parametrise a family of thick subcategories of the compact objects, which we call…

Category Theory · Mathematics 2026-01-07 Isaac Bird , Jordan Williamson , Alexandra Zvonareva

In this article we show how to calculate the group of automorphisms of flat K\"ahler manifolds. Moreover we are interested in the problem of classification of such manifolds up to biholomorphism. We consider these problems from two points…

Complex Variables · Mathematics 2022-10-06 Marek Hałenda , Rafał Lutowski

We show an equivalence of categories, over general $p$-adic bases, between finite locally $p^n$-torsion commutative group schemes and $\Int/p^n\Int$-modules in perfect $F$-gauges of Tor amplitude $[-1,0]$ with Hodge-Tate weights $0,1$. By…

Number Theory · Mathematics 2025-09-03 Keerthi Madapusi , Shubhodip Mondal

Let $k$ be a field. We characterize the group schemes $G$ over $k$, not necessarily affine, such that $\mathsf{D}_{\mathrm{qc}}(B_kG)$ is compactly generated. We also describe the algebraic stacks that have finite cohomological dimension in…

Algebraic Geometry · Mathematics 2016-09-08 Jack Hall , David Rydh

We calculate the number of the isomorphism class of the finite flat models over the ring of integers of an absolutely ramified $p$-adic field of constant group schemes of rank two over finite fields, by counting the rational points of a…

Number Theory · Mathematics 2020-11-24 Naoki Imai

We give an example of proper smooth fourfold over a perfect field k of characteristic p > 0 with asymmetric Hodge--Witt numbers in total degree 3. Our example is sharp both in terms of dimension and total degree. We arrive at our example by…

Algebraic Geometry · Mathematics 2026-04-06 Shizhang Li , Yuan Yang

We calculate the cluster modular groups of affine and doubly extended typecluster algebras in a uniform way by introducing a new family of quivers. We use this uniformdescription to construct a natural finite quotient of the cluster complex…

Combinatorics · Mathematics 2025-04-08 Dani Kaufman , Zachary Greenberg

We develop an alternative approach to the homological spectrum of a tensor-triangulated category through the lens of definable subcategories. This culminates in a proof that the homological spectrum is homeomorphic to a quotient of the…

Category Theory · Mathematics 2025-01-13 Isaac Bird , Jordan Williamson

We prove an equivalence of categories from formal complex structures with formal holomorphic maps to homotopy algebras over a simple operad with its associated homotopy morphisms. We extend this equivalence to complex manifolds. A complex…

Algebraic Topology · Mathematics 2015-01-19 Joan Millès

For the cyclic group $C_2$ we give a complete description of the derived category of perfect complexes of modules over the constant Mackey ring $\underline{\mathbb{Z}/\ell}$, for $\ell$ a prime. This is fairly simple for $\ell$ odd, but for…

Algebraic Topology · Mathematics 2023-07-03 Daniel Dugger , Christy Hazel , Clover May

For a smooth $p$-adic formal scheme over the ring of integers of a perfectoid field of mixed characteristic $(0,p)$ containing all $p$-power roots of unity, we prove that the prismatic cohomology of a locally finite free prismatic crystal…

Algebraic Geometry · Mathematics 2025-09-08 Takeshi Tsuji