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For $\Gamma_1$-structures on 3-manifolds, we give a very simple proof of Thurston's regularization theorem, first proved in \cite{thurston}, without using Mather's homology equivalence. Moreover, in the co-orientable case, the resulting…

Geometric Topology · Mathematics 2009-09-14 Francois Laudenbach , Gaël Meigniez

We construct, using geometric invariant theory, a quasi-projective Deligne-Mumford stack of stable graded algebras. We also construct a derived enhancement, which classifies twisted bundles of stable graded A-infinity-algebras. The tangent…

Algebraic Geometry · Mathematics 2015-07-28 Kai Behrend , Behrang Noohi

This paper concerns homological notions of regularity for noncommutative algebras. Properties of an algebra $A$ are reflected in the regularities of certain (complexes of) $A$-modules. We study the classical Tor-regularity and…

Rings and Algebras · Mathematics 2025-08-07 Ellen Kirkman , Robert Won , James J. Zhang

Gelfand - Na\u{i}mark theorem supplies a one to one correspondence between commutative $C^*$-algebras and locally compact Hausdorff spaces. So any noncommutative $C^*$-algebra can be regarded as a generalization of a topological space.…

Operator Algebras · Mathematics 2015-08-25 Petr Ivankov

We show that every connected graph can be approximated by a normal tree, up to some arbitrarily small error phrased in terms of neighbourhoods around its ends. The existence of such approximate normal trees has consequences of both…

Combinatorics · Mathematics 2021-02-05 Jan Kurkofka , Ruben Melcher , Max Pitz

As a ramification of a motivational discussion for previous joint work, in which equations of motion for the finite spectral action of the Standard Model were derived, we provide a new analysis of the results of the calculations herein,…

High Energy Physics - Theory · Physics 2008-11-26 R. A. D. Martins

For the quantum Heisenberg manifolds, using the action of Heisenberg group we construct a family of spectral triples. It is shown that associated Kasparov module is same for all these spectral triples. Then we show that element is…

Operator Algebras · Mathematics 2007-05-23 Partha Sarathi Chakraborty , Kalyan B. Sinha

We introduce a theory of stratifications of noncommutative stacks (i.e. presentable stable $\infty$-categories), and we prove a reconstruction theorem that expresses them in terms of their strata and gluing data. This reconstruction theorem…

Algebraic Geometry · Mathematics 2023-11-10 David Ayala , Aaron Mazel-Gee , Nick Rozenblyum

We consider in the plane the problem of reconstructing a domain from the normal derivative of its Green's function with pole at a fixed point in the domain. By means of the theory of conformal mappings, we obtain existence, uniqueness,…

Analysis of PDEs · Mathematics 2009-12-11 Virginia Agostiniani , Rolando Magnanini

For differential calculi on noncommutative algebras, we construct a twisted de Rham cohomology using flat connections on modules. This has properties similar, in some respects, to sheaf cohomology on topological spaces. We also discuss…

Quantum Algebra · Mathematics 2007-05-23 EJ Beggs , Tomasz Brzezinski

We study the isospectral deformations of the Eguchi-Hanson spaces along a torus isometric action in the noncompact noncommutative geometry. We concentrate on locality, smoothness and summability conditions of the nonunital spectral triples,…

Operator Algebras · Mathematics 2009-11-13 C. Yang

Grand Unified Theories (GUTs) are a very well motivated extensions of the Standard Model (SM), but the landscape of models and possibilities is overwhelming, and different patterns can lead to rather distinct phenomenologies. In this work…

High Energy Physics - Phenomenology · Physics 2017-09-08 Frank F. Deppisch , Tomas E. Gonzalo , Lukas Graf

A topology $\tau$ on a set $X$ is called maximal connected if it is connected, but no strictly finer topology $\tau^* > \tau$ is connected. We consider a construction of so-called tree sums of topological spaces, and we show how this…

General Topology · Mathematics 2018-12-04 Adam Bartoš

Taking a Feynman categorical perspective, several key aspects of the geometry of surfaces are deduced from combinatorial constructions with graphs. This provides a direct route from combinatorics of graphs to string topology operations via…

Algebraic Topology · Mathematics 2022-01-26 Clemens Berger , Ralph M. Kaufmann

A generalized-homology bordism-theory is constructed, such that for certain manifold homotopy stratified sets (MHSS; Quinn-spaces) homeomorphism-invariant geometric fundamental-classes exist. The construction combines three ideas: Firstly,…

Algebraic Topology · Mathematics 2023-10-16 Martin Rabel

We present a simple yet rigorous approach to the determination of the spectral dimension of random trees, based on the study of the massless limit of the Gaussian model on such trees. As a byproduct, we obtain evidence in favor of a new…

Condensed Matter · Physics 2008-11-26 C. Destri , L. Donetti

We study notions of hyperuniformity for invariant locally square-integrable point processes in regular trees. We show that such point processes are never geometrically hyperuniform, and if the diffraction measure has support in the…

Probability · Mathematics 2024-09-18 Mattias Byléhn

We study the topology of the space of positive scalar curvature metrics on high dimensional spheres and other spin manifolds. Our main result provides elements of infinite order in higher homotopy and homology groups of these spaces, which,…

Geometric Topology · Mathematics 2015-07-16 Bernhard Hanke , Thomas Schick , Wolfgang Steimle

After an introduction to some basic issues in non-commutative geometry (Gel'fand duality, spectral triples), we present a "panoramic view" of the status of our current research program on the use of categorical methods in the setting of…

Operator Algebras · Mathematics 2012-01-06 Paolo Bertozzini , Roberto Conti , Wicharn Lewkeeratiyutkul

We initiate a unified, axiomatic study of noncommutative algebras R whose prime spectra are, in a natural way, finite unions of commutative noetherian spectra. Our results illustrate how these commutative spectra can be functorially ``sewn…

Rings and Algebras · Mathematics 2007-05-23 Edward S. Letzter