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Related papers: Twisted conjugacy classes in unitriangular groups

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Non-Hermitian random matrices have been utilized in such diverse fields as dissipative and stochastic processes, mesoscopic physics, nuclear physics, and neural networks. However, the only known universal level-spacing statistics is that of…

Statistical Mechanics · Physics 2020-06-08 Ryusuke Hamazaki , Kohei Kawabata , Naoto Kura , Masahito Ueda

In the paper we prove an extension theorem for matrices with entries in H^{\infty}(U) for U being a Riemann surface of a special type. One of the main components of the proof is a Grauert type theorem for "holomorphic" vector bundles…

Complex Variables · Mathematics 2007-05-23 Alex Brudnyi

We construct two practical algorithms for twisted conjugacy classes of polycyclic-by-finite groups. The first algorithm determines whether two elements of a group are twisted conjugate for two given endomorphisms, under the condition that…

Group Theory · Mathematics 2021-10-22 Karel Dekimpe , Sam Tertooy

Given an ample Hausdorff groupoid $G$, a unital commutative ring $R$, and a discrete twist $(\Sigma,i,q)$, we establish a generalised uniqueness theorem for the twisted Steinberg algebra $A_R(G;\Sigma)$. By applying this theorem when $G$ is…

Rings and Algebras · Mathematics 2026-05-13 Rizalyn S. Bongcawel , Lyster Rey B. Cabardo , Lisa O. Clark

We extend the classical construction of operator colligations and characteristic functions. Consider the group $G$ of finite block unitary matrices of size $\alpha+\infty+...+\infty$ ($k$ times). Consider the subgroup $K=U(\infty)$, which…

Representation Theory · Mathematics 2017-08-08 Yury A. Neretin

Given a holomorphic vector bundle $E:EX X$ over a compact K\"ahler manifold, one introduces twisted GW-invariants of $X$ replacing virtual fundamental cycles of moduli spaces of stable maps $f: \Sigma \to X$ by their cap-product with a…

Algebraic Geometry · Mathematics 2007-05-23 Tom Coates , Alexander Givental

Let $n > 1$. Let $\{U_{ij}\}_{1 \leq i < j \leq n}$ be $\binom{n}{2}$ commuting unitaries on some Hilbert space $\mathcal{H}$, and suppose $U_{ji} := U_{ij}^*$, $1 \leq i < j \leq n$. An $n$-tuple of isometries $V = (V_1, \ldots ,V_n)$ on…

Operator Algebras · Mathematics 2022-05-10 Narayan Rakshit , Jaydeb Sarkar , Mansi Suryawanshi

We study the fundamental group of an open $n$-manifold $M$ of nonnegative Ricci curvature. We show that if there is an integer $k$ such that any tangent cone at infinity of the Riemannian universal cover of $M$ is a metric cone, whose…

Differential Geometry · Mathematics 2019-12-11 Jiayin Pan

Let $R$ be a commutative ring with $\Z(R)$ its set of zero-divisors. In this paper, we study the total graph of $R$, denoted by $\T(\Gamma(R))$. It is the (undirected) graph with all elements of $R$ as vertices, and for distinct $x, y\in…

Commutative Algebra · Mathematics 2010-02-01 Hamid Reza Maimani , Cameron Wickham , Siamak Yassemi

Let $M_n$ be an $n\times n$ real (resp. complex) Wigner matrix and $U_n\Lambda_n U_n^*$ be its spectral decomposition. Set $(y_1,y_2...,y_n)^T=U_n^*x$, where $x=(x_1,x_2,...,$ $x_n)^T$ is a real (resp. complex) unit vector. Under the…

Probability · Mathematics 2013-10-29 Zhigang Bao , Guangming Pan , Wang Zhou

We prove several new results on the combinatorial structures of the unit spheres of the norms induced by Thurston's metric on the tangent and cotangent spaces of the Teichm{\"u}ller space of a closed surface of negative Euler…

Geometric Topology · Mathematics 2026-05-27 Ken'Ichi Ohshika , Athanase Papadopoulos

Let $R$ be a commutative ring with identity and let $M$ be an $R$-module which is generated by $\mu$ elements but not fewer. We denote by $\operatorname{SL}_n(R)$ the group of the $n \times n$ matrices over $R$ with determinant $1$. We…

Commutative Algebra · Mathematics 2020-12-11 Luc Guyot

Let $A$ be a finite dimensional symmetric Hopf algebra over a field $k$. We show that there are $A$-modules whose Tate cohomology is not finitely generated over the Tate cohomology ring of $A$. However, we also construct $A$-modules which…

Rings and Algebras · Mathematics 2013-09-20 Van C. Nguyen

Given the unital C$^*$-algebra $A$, the unitary orbit of the projector $p_0=\begin{pmatrix}1 & 0 \\ 0 & 0 \end{pmatrix}$ in the C$^*$-algebra $M_2(A)$ of $2\times 2$ matrices with coefficients in $A$ is called in this paper, the Riemann…

Operator Algebras · Mathematics 2025-05-13 Esteban Andruchow , Gustavo Corach , Lázaro Recht , Alejandro Varela

We study various covering spectra for complete noncompact length spaces with universal covers (including Riemannian manifolds and the pointed Gromov Hausdorff limits of Riemannian manifolds with lower bounds on their Ricci curvature). We…

Differential Geometry · Mathematics 2014-04-30 Christina Sormani , Guofang Wei

The complex Ginibre ensemble is an $N\times N$ non-Hermitian random matrix over $\mathbb{C}$ with i.i.d. complex Gaussian entries normalized to have mean zero and variance $1/N$. Unlike the Gaussian unitary ensemble, for which the…

Probability · Mathematics 2018-05-24 Nicholas Crawford , Ron Rosenthal

We study conjugacy orbits of certain types of subalgebras in tracial von Neumann algebras. For any separable II$_1$ factor $N_0$ we construct a highly indecomposable non Gamma II$_1$ factor $N$ such that $N_0 \subset N$ and moreover every…

Operator Algebras · Mathematics 2025-08-29 David Gao , Srivatsav Kunnawalkam Elayavalli , Gregory Patchell , Hui Tan

Reciprocality in Kirchberg algebras with finitely generated K-groups is regarded as a K-theoretic duality through K-groups and strong extension groups. We will prove that the reciprocal Kirchberg algebra has a universal property with…

Operator Algebras · Mathematics 2025-11-11 Kengo Matsumoto , Taro Sogabe

We study the property of spectral-tightness of Riemannian manifolds, which means that the bottom of the spectrum of the Laplacian separates the universal covering space from any other normal covering space of a Riemannian manifold. We prove…

Differential Geometry · Mathematics 2021-10-13 Panagiotis Polymerakis

In this article we present new proofs for the boundedness and the compactness on $\ell^2$ of the Rhaly matrices, also known as terraced matrices. We completely characterize when such matrices belong to the Schatten class…

Functional Analysis · Mathematics 2025-08-29 Carlo Bellavita , Eugenio Dellepiane , Georgios Stylogiannis