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The Chern topological numbers of a material system are traditionally written in terms of the Berry curvature which depends explicitly on the material band structure and on the Bloch eigenwaves. Here, we demonstrate that it is possible to…

Optics · Physics 2018-04-04 Mário G. Silveirinha

We study the Brauer groups of regular conic bundles over elliptic curves defined over a number field $k$. We explicitly compute the Brauer group of the conic bundle when the singular fibres lie above $k$-points that are divisible by $2$ in…

Algebraic Geometry · Mathematics 2025-09-22 Abdulmuhsin Alfaraj

In 1996, Berline and Vergne gave a cohomological formula for the index of a transversally elliptic operator. In this paper we propose a new point of view where the cohomological formulae make use of equivariant Chern characters with…

Differential Geometry · Mathematics 2008-12-18 Paul-Emile Paradan , Michèle Vergne

We study the relationship between the period and the index of a principal homogeneous space over an abelian variety, obtaining results which generalize work of Cassels and Lichtenbaum on curves of genus one. In addition, we show that the…

Number Theory · Mathematics 2007-05-23 Pete L. Clark

Given a number field $F$ with ring of integers $\mathcal{O}_{F}$, one can associate to any torsion free subgroup of $\operatorname{SL}(2,\mathcal{O}_{F})$ of finite index a complete Riemannian manifold of finite volume with fibered cusp…

Differential Geometry · Mathematics 2026-02-17 Werner Mueller , Frédéric Rochon

Classical approximation bases such as Chebyshev polynomials provide principled and interpretable representations, but their multivariate tensor-product constructions scale exponentially with dimension and impose axis-aligned structure that…

Machine Learning · Computer Science 2026-04-07 Milo Coombs

We establish a local topological obstruction to the simultaneous flattening of Berry curvature in spin--orbit-coupled Bose--Einstein condensates (SOC BECs), which remains valid even when the global Chern number vanishes. For a generic…

Differential Geometry · Mathematics 2026-02-11 Alexander Pigazzini , Magdalena Toda

For a countable ordinal a we denote by C_a the class of separable, reflexive Banach spaces whose Szlenk index and the Szlenk index of their dual are bounded by a. We show that each C_a admits a separable, reflexive universal space. We also…

Functional Analysis · Mathematics 2007-06-06 Edward Odell , Thomas Schlumprecht , András Zsák

Given a $(0,p)$-mixed characteristic complete discrete valued field $\mathcal{K}$ we define a class of finite field extensions called \emph{pseudo-perfect} extensions such that the natural restriction map on the mod-$p$ Milnor $K$-groups is…

Number Theory · Mathematics 2025-10-17 Srinivasan Srimathy

In this paper, we revisit the construction of the hairy graph complexes associated to a cyclic operad, by exploiting modules over the appropriate twisted linearization of the downward Brauer category (and working over a field of…

Algebraic Topology · Mathematics 2025-12-24 Geoffrey Powell

We use Galois group actions on \'etale cohomology to prove results of formality for dg-operads and dg-algebras with torsion coefficients. Our theory applies, among other related constructions, to the dg-operad of singular chains on the…

Algebraic Topology · Mathematics 2025-08-05 Joana Cirici , Geoffroy Horel

On an odd-dimensional oriented hyperbolic manifold of finite volume with strongly acyclic coefficient systems, we derive a formula relating analytic torsion with the Reidemeister torsion of the Borel-Serre compactification of the manifold.…

Differential Geometry · Mathematics 2019-03-18 Werner Mueller , Frédéric Rochon

For an $\E$-ring spectrum $R$ and a map $f:X\to Pic(R)$ of spaces, the Thom spectrum $\T f$ is a comodule over $R\otimes\Si X$. In this parper we study the topological coHochschild homology of $R\otimes\Si X$ with coefficient $\T f$. More…

Algebraic Topology · Mathematics 2026-01-19 Jiaxi Zha

The integer Cech cohomology of canonical projection tilings of dimension three and codimension three is derived. These formulae are then evaluated for several icosahedral tilings known from the literature. Rather surprisingly, the…

Dynamical Systems · Mathematics 2012-02-15 F. Gähler , J. Hunton , J. Kellendonk

The principal aim of this paper is to construct torsion cohomology classes in the initial terms of a spectral sequence computing the cohomology of a Kottwitz-Harris-Taylor Shimura variety. Beside we produce some global congruences between…

Number Theory · Mathematics 2015-12-08 Pascal Boyer

We compute an asymptotic expansion in $1/c$ of the limit in $n$ of the empirical spectral measure of the adjacency matrix of an Erd\H{o}s-R\'enyi random graph with $n$ vertices and parameter $c/n$. We present two different methods, one of…

Probability · Mathematics 2017-01-05 Nathanael Enriquez , Laurent Menard

We extend the computations in [AGM1, AGM2, AGM3] to find the cohomology in degree five of a congruence subgroup Gamma of SL(4,Z) with coefficients in a field K, twisted by a nebentype character eta, along with the action of the Hecke…

Number Theory · Mathematics 2018-06-25 Avner Ash , Paul E. Gunnells , Mark McConnell

Following [14], we compute the motivic cohomology ring of the Nisnevich classifying space of the unitary group associated to the standard split hermitian form of a quadratic extension. This provides us with subtle characteristic classes…

Algebraic Geometry · Mathematics 2022-08-08 Fabio Tanania

For any finite group G, we construct a spectral sequence for computing the Bredon cohomology of a G-CW complex X, starting with the cohomology of X^H/\cup_{K>H}X^K with suitable local coefficients, for various H \leq G.

Algebraic Topology · Mathematics 2013-01-08 David Blanc , Debasis Sen

We produce a criterion for open sets in projective $n$-space over a separably closed field to have \'etale cohomological dimension bounded by $2n-3$. We use the criterion to exhibit a scheme for which \'etale cohomological dimension is…

Commutative Algebra · Mathematics 2010-12-01 Manoj Kummini , Uli Walther