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Related papers: The spectral site revisited

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We construct classifying $\infty$-topoi by showing that the $(\infty,2)$-category of topoi has weighted limits. We show that several prestacks of interest have a classifying topos, including the prestack of spectra.

Category Theory · Mathematics 2026-01-29 Ivan Di Liberti , Nicholas Meadows

We initiate a systematic study of spectral theory for bounded-degree Borel pmp graphs. Specifically, we study spectral properties of the associated adjacency and Laplacian operators. We start with proving a spectral characterization of…

Logic · Mathematics 2026-02-06 Cecelia Higgins , Pieter Spaas , Alexander Tenenbaum

In a previous work we introduced an elementary method to analyze the periodicity of a generating function defined by a single equation y=G(x,y). This was based on deriving a single set-equation Y = Gammma(Y) defining the spectrum of the…

Logic · Mathematics 2009-11-16 Jason Bell , Stanley Burris , Karen Yeats

We introduce a new topological invariant of a rigidly-compactly generated tensor-triangulated category and two new notions of support. The first is based on smashing subcategories: it is unknown whether the frame of smashing subcategories…

Category Theory · Mathematics 2023-09-01 Scott Balchin , Greg Stevenson

The finite spectrum of a first-order sentence is the set of positive integers that are the sizes of its models. The class of finite spectra is known to be the same as the complexity class NE. We consider the spectra obtained by limiting…

Logic in Computer Science · Computer Science 2023-06-22 Anuj Dawar , Eryk Kopczyński

The study of spectral graph determination is a fascinating area of research in spectral graph theory and algebraic combinatorics. This field focuses on examining the spectral characterization of various classes of graphs, developing methods…

Combinatorics · Mathematics 2025-04-14 Igal Sason , Noam Krupnik , Suleiman Hamud , Abraham Berman

Based on tiles and on the Coven-Meyerowitz property, we present some examples and some general constructions of spectral subsets of integers.

Number Theory · Mathematics 2017-06-21 Dorin Ervin Dutkay , Isabelle Kraus

We discuss the problem of characterizing the property of a Grothendieck topos to satisfy a given 'geometric' invariant as a property of its sites of definition, and indicate a set of general techniques for establishing such criteria. We…

Category Theory · Mathematics 2013-04-26 Olivia Caramello

Categorial methods for generating new local algebras from old ones are presented. A direct proof of the differential structure of the prolongations of a manifold is proposed.

Category Theory · Mathematics 2007-09-05 Margherita Barile , Fiorella Barone , Wlodzimierz M. Tulczyjew

We classify 0-dimensional spectral triples over complex and real algebras and provide some general statements about their differential structure. We investigate also whether such spectral triples admit a symmetry arising from the Hopf…

q-alg · Mathematics 2016-09-08 Mario Paschke , Andrzej Sitarz

We introduce, comment and develop the Scott adjunction, mostly from the point of view of a category theorist. Besides its technical and conceptual aspects, in a nutshell we provide a categorification of the Scott topology over a posets with…

Category Theory · Mathematics 2022-01-27 Ivan Di Liberti

This paper studies the foundations of the geometric fixed point functor in multiplicative equivariant stable homotopy theory. We introduce a new class of equivariant orthogonal spectra called generalized orbit desuspension spectra and…

Algebraic Topology · Mathematics 2024-12-23 Andrew J. Blumberg , Michael A. Mandell

The aim of this project is to attach a geometric structure to the ring of integers. It is generally assumed that the spectrum $\mathrm{Spec}(\mathbb{Z})$ defined by Grothendieck serves this purpose. However, it is still not clear what…

Logic · Mathematics 2016-09-26 Boris Zilber , Lubna Shaheen

As the prototypical category, $\mathbf{Set}$ has many properties which make it special amongst categories. From the point of view of mathematical logic, one such property is that $\mathbf{Set}$ has enough structure to "properly" formalise…

Category Theory · Mathematics 2020-11-30 Jordan Mitchell Barrett

Two graphs are co-spectral if their respective adjacency matrices have the same multi-set of eigenvalues. A graph is said to be determined by its spectrum if all graphs that are co-spectral with it are isomorphic to it. We consider these…

Logic in Computer Science · Computer Science 2016-09-15 Anuj Dawar , Simone Severini , Octavio Zapata

We introduce a formalism to produce several families of spectral sequences involving the derived functors of the limit and colimit functors over a finite partially ordered set. The first type of spectral sequences involves the left derived…

Commutative Algebra · Mathematics 2022-10-18 Josep Àlvarez Montaner , Alberto F. Boix , Santiago Zarzuela

Neural networks represent more features than they have dimensions via superposition, forcing features to share representational space. Current methods decompose activations into sparse linear features but discard geometric structure. We…

Machine Learning · Computer Science 2026-02-03 Georgi Ivanov , Narmeen Oozeer , Shivam Raval , Tasana Pejovic , Shriyash Upadhyay , Amir Abdullah

We establish the various properties as well as diverse relations of the ascent and descent spectra for bounded linear operators. We specially focus on the theory of subspectrum. Furthermore, we construct a new concept of convergence for…

Functional Analysis · Mathematics 2018-08-27 Nassim Athmouni , Mondher Damak , Chiraz Jendoubi

We develop Spectral-Operator Calculus (SOC), an axiomatic calculus for scalar evaluation of operator-generated spectral observables. This paper (SOC-I) treats the self-adjoint setting, where observables are bounded Borel transforms and…

Functional Analysis · Mathematics 2025-12-29 John Homer

We define a class of sites such that the associated topos is equivalent to the category of smooth sets (representations) of some locally prodiscrete monoids (to be defined). Examples of locally prodiscrete monoids include profinite groups…

Number Theory · Mathematics 2017-11-08 Satoshi Kondo , Seidai Yasuda