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For any connected component $H_0$ of the space of real meromorphic functions we build a compactification $N(H_0)$ of the space $H_0$. Then we express the Euler characteristics of the spaces $H_0$ and $N(H_0)$ in terms of topological…

Complex Variables · Mathematics 2017-08-22 S. V. Shadrin

For a group $G$ of not prime power order, Oliver showed that the obstruction for a finite CW-complex $F$ to be the fixed point set of a contractible finite $G$-CW-complex is the Euler characteristic $\chi(F)$. He also has the similar…

Algebraic Topology · Mathematics 2025-04-02 Sylvain Cappell , Shmuel Weinberger , Min Yan

Let $M$ be a compact 3-manifold with a triangulation $\tau$. We give an inequality relating the Euler characteristic of a surface $F$ normally embedded in $M$ with the number of normal quadrilaterals in $F$. This gives a relation between a…

Geometric Topology · Mathematics 2008-10-02 Tejas Kalelkar

Given a simple, simply connected compact Lie group G, let M be a G-space. We describe the quantization of the category of positive energy representations of the loop group of G at a given level and parametrized over the loop space LM. This…

Algebraic Topology · Mathematics 2018-05-17 Nitu Kitchloo

In this short note we present a generating function computing the compactly supported Euler characteristic $\chi_c(F(X, n), K^{\boxtimes n})$ of the configuration spaces on a topologically stratified space $X$, with $K$ a constructible…

Algebraic Topology · Mathematics 2023-04-21 Louis Hainaut

The equivariant bootstrap class in the Kasparov category of actions of a finite group G consists of those actions that are equivalent to one on a Type I C*-algebra. Using a result by Arano and Kubota, we show that this bootstrap class is…

Operator Algebras · Mathematics 2026-02-25 Ralf Meyer , George Nadareishvili

It is well known that the Euler characteristic of the cohomology of a complex algebraic variety coincides with the Euler characteristic of its cohomology with compact support. An old result of G. Laumon asserts that a relative version of…

Algebraic Geometry · Mathematics 2014-10-09 Rahbar Virk

For a countable group $G$ we construct a small, idempotent complete, symmetric monoidal, stable $\infty$-category $\mathrm{KK}^{G}_{\mathrm{sep}}$ whose homotopy category recovers the triangulated equivariant Kasparov category of separable…

Operator Algebras · Mathematics 2025-12-03 Ulrich Bunke , Alexander Engel , Markus Land

We prove the conjectures of Graham-Kumar and Griffeth-Ram concerning the alternation of signs in the structure constants for torus-equivariant K-theory of generalized flag varieties G/P. These results are immediate consequences of an…

Algebraic Geometry · Mathematics 2017-03-14 Dave Anderson , Stephen Griffeth , Ezra Miller

By the work of J.Huh, one can interpret binomial coefficients as a solution to an intersection problem on a permutohedral variety $X_E$. Applying Hirzebruch-Riemann-Roch, this intersection problem is equivalent to computing Euler…

Algebraic Geometry · Mathematics 2025-10-16 Vincenzo Galgano , Hanieh Keneshlou , Mateusz Michalek

A $Q$-manifold $M$ is a supermanifold endowed with an odd vector field $Q$ squaring to zero. The Lie derivative $L_Q$ along $Q$ makes the algebra of smooth tensor fields on $M$ into a differential algebra. In this paper, we define and study…

Mathematical Physics · Physics 2015-05-13 S. L. Lyakhovich , E. A. Mosman , A. A. Sharapov

We give explicit computations of the $\Gamma$-Euler characteristic of several families of orbit space definable translation groupoids. These include the translation groupoids associated to finite-dimensional linear representations of the…

Algebraic Topology · Mathematics 2025-08-27 Carla Farsi , Hannah Mobley , Christopher Seaton

For any compact Lie group $G$ and any $n$ we construct a smooth $G$-manifold $U_n(G)$ such that any smooth $n$-dimensional $G$-manifold can be embedded in $U_n(G)$ with a trivial normal bundle. Furthermore, we show that such embeddings are…

Algebraic Topology · Mathematics 2025-01-03 Arthur G. Wasserman

The local Euler obstructions and the Euler characteristics of linear sections with all hyperplanes on a stratified projective variety are key geometric invariants in the study of singularity theory. Despite their importance, in general it…

Algebraic Geometry · Mathematics 2021-05-11 Xiping Zhang

We construct a global geometric model for complex analytic equivariant elliptic cohomology for all compact Lie groups. Cocycles are specified by functions on the space of fields of the two-dimensional sigma model with background gauge…

Algebraic Topology · Mathematics 2020-08-25 Daniel Berwick-Evans , Arnav Tripathy

We study equivariant Arakelov-Euler characteristics of hermitian sheaves on arithmetic varieties which support a tame action by a finite group G. The tameness of the group action allows us to produce an equivariant Arakelov-Euler…

Number Theory · Mathematics 2007-05-23 T. Chinburg , G. Pappas , M. J. Taylor

We extend Ghys' theory about semiconjugacy to the world of measurable cocycles. More precisely, given a measurable cocycle with values into $\text{Homeo}^+(\mathbb{S}^1)$, we can construct a $\text{L}^\infty$-parametrized Euler class in…

Geometric Topology · Mathematics 2021-01-29 Alessio Savini

Consider a complex algebraic group $G$ acting on a smooth variety $M$ with finitely many orbits, and let $\Omega$ be an orbit. The following three invariants of $\Omega\subset M$ can be characterized axiomatically: (1) the equivariant…

Algebraic Geometry · Mathematics 2019-12-10 Laszlo M. Feher , Richard Rimanyi , Andrzej Weber

This note proves that, as K-theory elements, the symbol classes of the de Rham operator and the signature operator on a closed manifold of even dimension are congruent mod 2. An equivariant generalization is given pertaining to the…

Geometric Topology · Mathematics 2008-04-08 James F. Davis , Pisheng Ding

If two G-manifolds are G-cobordant then characteristic numbers corresponding to the fixed point sets (submanifolds) of subgroups of G and to normal bundles to these sets coincide. We construct two analogues of these characteristic numbers…

Algebraic Geometry · Mathematics 2014-06-18 Wolfgang Ebeling , Sabir M. Gusein-Zade