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We present an Eilenberg-Steenrod-like axiomatic framework for equivariant coarse homology and cohomology theories. We also discuss a general construction of such coarse theories from topological ones and the associated transgression maps. A…

Algebraic Topology · Mathematics 2022-07-27 Christopher Wulff

We use tools of representation theory to get a better understanding of the cohomology of graded group schemes. For that, we focus our attention on the case in which the base field is of characteristic $p > 0$. Using as inspiration the work…

Algebraic Geometry · Mathematics 2014-12-02 Camil I. Aponte Román

Let $\mathbb{G}$ be a split connected reductive group scheme over the ring of integers $\mathfrak{o}$ of a finite extension $L|\mathbb{Q}_p$ and $\lambda\in X(\mathbb{T})$ an algebraic character of a split maximal torus…

Representation Theory · Mathematics 2019-10-16 Andrés Sarrazola Alzate

A Stein covering of a complex manifold may be used to realise its analytic cohomology in accordance with the Cech theory. If, however, the Stein covering is parameterised by a smooth manifold rather than just a discrete set, then we…

Complex Variables · Mathematics 2007-05-23 Toby Bailey , Michael Eastwood , Simon Gindikin

We say A is a quasi-normal subgroup of the group G if the commensurator of A in G is all of G. We develop geometric versions of commensurators in finitely generated groups. In particular, g is an element of the commensurator of A in G iff…

Group Theory · Mathematics 2009-12-31 Gregory R. Conner , Michael L. Mihalik

Characterizing graphs by their spectra is an important topic in spectral graph theory, which has attracted a lot of attention of researchers in recent years. It is generally very hard and challenging to show a given graph to be determined…

Combinatorics · Mathematics 2020-11-02 Wei Wang , Fenjin Liu , Wei Wang

Using determinantal schemes, we construct explicit cycles in the higher Chow complex of BGL that represent the universal Chern classes in higher Chow groups. As an application, we use these cycles, along with a canonical \emph{stable moving…

Algebraic Geometry · Mathematics 2023-05-24 Paulo Lima-Filho

We investigate strictly developable simple complexes of groups with arbitrary local groups, or equivalently, group actions admitting a strict fundamental domain. We introduce a new method for computing the cohomology of such groups. We also…

Group Theory · Mathematics 2022-10-10 Nansen Petrosyan , Tomasz Prytuła

Kaplansky introduced the notions of CCR and GCR $C^*$-algebras because they have a tractable representation theory. Many years later, he introduced the notions of CCR and GCR rings. In this paper we characterize when the algebra of an ample…

Operator Algebras · Mathematics 2019-08-28 Lisa Orloff Clark , Benjamin Steinberg , Daniel W van Wyk

In previous definition of $\mathrm{E}$-theory, separability of the $\mathrm{C}^*$-algebras is needed either to construct the composition product or to prove the long exact sequences. Considering the latter, the potential failure of the long…

Operator Algebras · Mathematics 2022-12-15 Christopher Wulff

Coherent sheaves on general complex manifolds do not necessarily have resolutions by finite complexes of vector bundles. However D. Toledo and Y.L.L. Tong showed that one can resolve coherent sheaves by objects analogous to chain complexes…

Algebraic Topology · Mathematics 2025-01-01 Cheyne Glass , Micah Miller , Thomas Tradler , Mahmoud Zeinalian

We study partial homology and cohomology from ring theoretic point of view via the partial group algebra $\mathbb{K}_{par}G$. In particular, we link the partial homology and cohomology of a group $G$ with coefficients in an irreducible…

Group Theory · Mathematics 2023-11-10 Marcelo Muniz Alves , Mikhailo Dokuchaev , Dessislava H. Kochloukova

A ring R is called an E-ring if the canonical homomorphism from R to the endomorphism ring End(R_Z) of the additive group R_Z, taking any r in R to the endomorphism left multiplication by r turns out to be an isomorphism of rings. In this…

Logic · Mathematics 2007-05-23 Rüdiger Göbel , Saharon Shelah , Lutz Strüngmann

In Remarks on Galois Cohomology and Definability [2], Pillay introduced definable Galois cohomology, a model-theoretic generalization of Galois cohomology. Let $M$ be an atomic and strongly $\omega$-homogeneous structure over a set of…

Logic · Mathematics 2026-01-12 David Meretzky

We generalize a cohomological construction of representations due to Lusztig from the hyperspecial case to arbitrary parahoric subgroups of a reductive group over a local field, which splits over an unramified extension. We compute the…

Representation Theory · Mathematics 2019-03-15 Charlotte Chan , Alexander B. Ivanov

Let $\Gamma$ be a dense countable subgroup of $\mathbb{R}$. Then, consider $IE(\Gamma)$; the group of piecewise linear bijections of $[0,1]$ with finitely many angles, all in $\Gamma$. We introduce and systematically study a family of…

Group Theory · Mathematics 2023-07-06 Owen Tanner

The family of cycle completable graphs has several cryptomorphic descriptions, the equivalence of which has heretofore been proven by a laborious implication-cycle that detours through a motivating matrix completion problem. We give a…

Combinatorics · Mathematics 2023-09-06 Maria Chudnovsky , Ian Malcolm Johnson McInnis

In this paper, we propose another characterization of the generalized mirror transformation on the quantum cohomology rings of general type projective hypersurfaces. This characterics is useful for explicit determination of the form of the…

Algebraic Geometry · Mathematics 2009-10-31 Masao Jinzenji

For a connected quasi-split reductive algebraic group $G$ over a field $k$, which is either a finite field or a non-archimedean local field, $\theta$ an involutive automorphism of $G$ over $k$, let $K =G^\theta$. Let $K^1=[K^0,K^0]$, the…

Representation Theory · Mathematics 2019-03-06 Dipendra Prasad

In this paper, motivated by Chen--Ruan's stringy orbifold theory on almost complex orbifolds, we construct a new cohomology ring $\mathscr H^\ast_{G,cs}(X)$ for an equivariant almost complex pair $(X,G)$, where $X$ is a compact connected…

Symplectic Geometry · Mathematics 2018-12-06 Bohui Chen , Cheng-Yong Du , Tiyao Li