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We compute the equivariant cohomology Chern character of the index of elliptic operators along the leaves of the foliation of a flat bundle. The proof is based on the study of certain algebras of pseudodifferential operators and uses…

dg-ga · Mathematics 2008-02-03 Victor Nistor

We obtain the equivariant K-homology of the classifying space \underline{E}W for W a right-angled or, more generally, an even Coxeter group. The key result is a formula for the relative Bredon homology of \underline{E}W in terms of Coxeter…

K-Theory and Homology · Mathematics 2009-08-07 Ruben Sanchez-Garcia

In this paper the cosheaf homology is investigated from different viewpoints: the behavior under site morphisms, connections with Cech homology via spectral sequences, and description of cosheaf homology using hypercoverings. It is proved…

Algebraic Topology · Mathematics 2025-04-24 Andrei V. Prasolov

Transcendental Brauer elements are notoriously difficult to compute. Work of Wittenberg, and later, Ieronymou, gives a method for computing 2-torsion transcendental classes on surfaces that have a genus 1 fibration with rational 2-torsion…

Algebraic Geometry · Mathematics 2012-02-29 Bianca Viray

For an odd-dimensional oriented hyperbolic manifold with cusps and strongly acyclic coefficient systems we define the Reidemeister torsion of the Borel-Serre compactification of the manifold using bases of cohomology classes defined via…

Spectral Theory · Mathematics 2015-07-08 Jonathan Pfaff

We study Brou\'e's abelian defect group conjecture for groups of Lie type using the recent theory of perverse equivalences and Deligne--Lusztig varieties. Our approach is to analyze the perverse equivalence induced by certain…

Representation Theory · Mathematics 2012-07-03 David A. Craven

We show that in locally-ringed connected topoi the primes dividing the period and index of a Brauer class coincide. The result applies in particular to Brauer classes on connected schemes, algebraic stacks, topological spaces and to the…

Algebraic Geometry · Mathematics 2014-08-08 Benjamin Antieau , Ben Williams

We bound the symbol length of elements in the Brauer group of a field $K$ containing a $C_m$ field (for example any field containing an algebraically closed field or a finite field), and solve the local exponent-index problem for a $C_m$…

Rings and Algebras · Mathematics 2014-02-04 Eliyahu Matzri

An index theory for projective families of elliptic pseudodifferential operators is developed. The topological and the analytic index of such a family both take values in twisted K-theory of the parametrizing space, X. The main result is…

Differential Geometry · Mathematics 2014-11-11 Varghese Mathai , Richard B Melrose , Isadore M Singer

We revisit the definition of transverse frames and tetrad choices with regards to its application to numerically generated spacetimes, in particular those from the merger of binary black holes. We introduce the concept of local and…

General Relativity and Quantum Cosmology · Physics 2021-08-25 Nicole Rosato , Hiroyuki Nakano , Carlos O. Lousto

Let $F$ be the function field of a smooth curve over the $p$-adic number field $\Q_p$. We show that for each prime-to-$p$ number $n$ the $n$-torsion subgroup $\H^2(F,\mu_n)={}_n\Br(F)$ is generated by $\Z/n$-cyclic classes; in fact the…

Rings and Algebras · Mathematics 2013-07-15 Eric Brussel , Kelly McKinnie , Eduardo Tengan

The space of smotth functions and vector fields on $\R^d$ is a Lie subalgebra of the (graded) Lie algebra $T\_{poly}(\R^d)$, equipped with the Scouten bracket. In this paper, we compute the cohomology of this subalgebra for the adjoint…

Quantum Algebra · Mathematics 2007-05-23 Walid Aloulou , Didier Arnal , Ridha Chatbouri

These notes form the next episode in a series of articles dedicated to a detailed proof of a cohomological index formula for transversally elliptic pseudo-differential operators and applications. The first two chapters are already available…

Differential Geometry · Mathematics 2008-01-21 Paul-Emile Paradan , Michèle Vergne

It is shown that the known notion of selective coideal can be extended to a family $\mathcal{H}$ of subsets of $\mathcal{R}$, where $(\mathcal{R},\leq,r)$ is a topological Ramsey space in the sense of Todorcevic (see \cite{todo}). Then it…

Logic · Mathematics 2007-12-17 José Mijares , Jesús Nieto

In the world of chain complexes E_n-algebras are the analogues of based n-fold loop spaces in the category of topological spaces. Fresse showed that operadic E_n-homology of an E_n-algebra computes the homology of an n-fold algebraic…

Algebraic Topology · Mathematics 2015-10-30 Birgit Richter , Stephanie Ziegenhagen

For a locally convex Lie group with the Trotter property, we prove that the space of k-times differentiable vectors of a unitary representation is equal to the intersection of domains of k-fold products of the Lie algebra action. The result…

Representation Theory · Mathematics 2012-11-19 Hadi Salmasian , Karl-Hermann Neeb

Let Y be a closed oriented 3-manifold with a contact form such that all Reeb orbits are nondegenerate. The embedded contact homology (ECH) index associates an integer to each relative 2-dimensional homology class of surfaces whose boundary…

Symplectic Geometry · Mathematics 2008-10-22 Michael Hutchings

Building on recent results by A. Blanc, M. Robalo and the authors, we present an $\ell$-adic trace formula for smooth and proper dg-categories over a base $\mathbb{E}_{\infty}$-algebra $B$. We also give a variant when $B$ is only an…

Algebraic Geometry · Mathematics 2016-05-31 B. Toën , G. Vezzosi

We prove that the group of normalized cohomological invariants of degree 3 modulo the subgroup of semidecomposable invariants of a semisimple split linear algebraic group G is isomorphic to the torsion part of the Chow group of codimension…

Algebraic Geometry · Mathematics 2015-08-19 Alexander Merkurjev , Alexander Neshitov , Kirill Zainoulline

We prove that every Brauer class over a field splits over a torsor under an abelian variety. If the index of the class is not congruent to 2 modulo 4, we show that the Albanese variety of any smooth curve of positive genus that splits the…

Algebraic Geometry · Mathematics 2018-11-14 Wei Ho , Max Lieblich