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Using the unbounded picture of analytical K-homology, we associate a well-defined K-homology class to an unbounded symmetric operator satisfying certain mild technical conditions. We also establish an ``addition formula'' for the Dirac…

K-Theory and Homology · Mathematics 2007-05-23 Hela Bettaieb , Michel Matthey , Alain Valette

We study the vanishing cycles of a one-parameter smoothing of a complex analytic space and show that the weight filtration on its perverse cohomology sheaf of the highest degree is quite close to the monodromy filtration so that its graded…

Algebraic Geometry · Mathematics 2010-08-11 Alexandru Dimca , Morihiko Saito

The real cohomology of the space of imbeddings of S^1 into R^n, n>3, is studied by using configuration space integrals. Nontrivial classes are explicitly constructed. As a by-product, we prove the nontriviality of certain cycles of…

Geometric Topology · Mathematics 2014-10-01 Alberto S. Cattaneo , Paolo Cotta-Ramusino , Riccardo Longoni

We study some topological spaces that can be considered as hyperspaces associated to noncommutative spaces. More precisely, for a NC compact space associated to a unital C*-algebra, we consider the set of closed projections of the second…

Operator Algebras · Mathematics 2017-01-09 Maysam Maysami Sadr

This is a report on the present state of the problem of determining the dimension of the Nichols algebra associated to a rack and a cocycle. This is relevant for the classification of finite-dimensional complex pointed Hopf algebras whose…

Quantum Algebra · Mathematics 2011-03-22 N. Andruskiewitsch , F. Fantino , G. A. Garcia , L. Vendramin

It is known that irreducible noncommutative differential structures over $\Bbb F_p[x]$ are classified by irreducible monics $m$. We show that the cohomology $H_{\rm dR}^0(\Bbb F_p[x]; m)=\Bbb F_p[g_d]$ if and only if ${\rm Tr}(m)\ne 0$,…

Quantum Algebra · Mathematics 2019-02-05 M. E. Bassett , S. Majid

We show that any measurable solution of the cohomological equation for a H\"older linear cocycle over a hyperbolic system coincides almost everywhere with a H\"older solution. More generally, we show that every measurable invariant…

Dynamical Systems · Mathematics 2018-07-25 Clark Butler

The notion of homomorphism indistinguishability offers a combinatorial framework for characterizing equivalence relations of graphs, in particular equivalences in counting logics within finite model theory. That is, for certain graph…

Logic in Computer Science · Computer Science 2025-06-26 Georg Schindling

For a smooth Morse-Smale vector field with Lyapunov constraints (Lyapunov function) one shows how and why the non-triviality of the cohomology, as concluded from its additive structure, detects rest points and the multiplicative structure…

Dynamical Systems · Mathematics 2024-10-15 Dan Burghelea

We use hypersurface support to classify thick (two-sided) ideals in the stable categories of representations for several families of finite-dimensional integrable Hopf algebras: bosonized quantum complete intersections, quantum Borels in…

Representation Theory · Mathematics 2023-05-03 Cris Negron , Julia Pevtsova

We begin the study the algebraic topology of semi-coarse spaces, which are generalizations of coarse spaces that enable one to endow non-trivial `coarse-like' structures to compact metric spaces, something which is impossible in coarse…

Algebraic Topology · Mathematics 2024-10-01 Antonio Rieser , Jonathan Treviño-Marroquín

Shellable complexes are homotopy equivalent to a wedge of spheres of possibly different dimensions, so that the (co)homology of the constant functor over the complex is concentrated in those degrees. In this work, we introduce the concept…

Algebraic Topology · Mathematics 2025-09-30 Guille Carrión Santiago , Antonio Díaz Ramos

This paper proposes a new theoretical perspective for studying the Hodge conjecture through an analytical framework based on constraint geometry. Our theory begins with a key observation: in compatible pair Spencer theory, a "differential…

General Mathematics · Mathematics 2025-08-12 Dongzhe Zheng

Let $t$ be a positive integer. Following work of D. M. Davis, we study the topology of complex-projective product spaces, i.e. quotients of cartesian products of odd dimensional spheres by the diagonal $S^1$-action, and of the $t$-torsion…

Algebraic Topology · Mathematics 2013-11-07 Jesus Gonzalez , Maurilio Velasco

By a result of Gerstenhaber and Schack the simplicial cohomology ring $H^*(\mathcal{C};k)$ of a poset $\mathcal{C}$ is isomorphic to the Hochschild cohomology ring $HH^*(k\mathcal{C})$ of the category algebra $k\mathcal{C}$, where the poset…

K-Theory and Homology · Mathematics 2022-06-22 I. -I. Simion , C. -C. Todea

In determining when a four-dimensional ellipsoid can be symplectically embedded into a ball, McDuff and Schlenk found an infinite sequence of "ghost" obstructions that generate an infinite "ghost staircase" determined by the even index…

Symplectic Geometry · Mathematics 2018-04-18 Dan Cristofaro-Gardiner , Richard Hind , Dusa McDuff

We introduce the general notions of an overconvergent site and a constructible crystal on an overconvergent site. We show that if $V$ is a geometric materialization of a locally noetherian formal scheme $X$ over an analytic space $O$…

Algebraic Geometry · Mathematics 2022-09-19 Bernard Le Stum

We study the irreducible components of special loci of curves whose group of symmetries is given as certain group extension. We introduce some relative Hurwitz data, which we show by using mixed \'etale cohomology theory, identifies some…

Algebraic Geometry · Mathematics 2020-06-22 Benjamin Collas , Sylvain Maugeais

We discuss the cohomology of superforms and integral forms from a new perspective based on a recently proposed Hodge dual operator. We show how the superspace constraints (a.k.a. rheonomic parametrisation) are translated from the space of…

High Energy Physics - Theory · Physics 2015-12-09 Leonardo Castellani , Roberto Catenacci , Pietro Antonio Grassi

Continual learning systems operating in fixed-dimensional spaces face a fundamental geometric barrier: the flat manifold problem. When experience is represented as a linear trajectory in Euclidean space, the geodesic distance between…

Machine Learning · Computer Science 2025-12-23 Xin Li