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Related papers: Higher genus universally decodable matrices (UDMG)

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Universally decodable matrices (UDMs) can be used for coding purposes when transmitting over slow fading channels. These matrices are parameterized by positive integers $L$ and $N$ and a prime power $q$. The main result of this paper is…

Information Theory · Computer Science 2007-07-13 Ashwin Ganesan , Pascal O. Vontobel

The notion of universally decodable matrices (UDMs) was recently introduced by Tavildar and Viswanath while studying slow fading channels. It turns out that the problem of constructing UDMs is tightly connected to the problem of…

Information Theory · Computer Science 2007-07-13 Pascal O. Vontobel , Ashwin Ganesan

Universally decodable matrices can be used for coding purposes when transmitting over slow fading channels. These matrices are parameterized by positive integers $L$ and $n$ and a prime power $q$. Based on Pascal's triangle we give an…

Information Theory · Computer Science 2007-07-13 Pascal O. Vontobel , Ashwin Ganesan

Euclidean distance matrices (EDM) are symmetric nonnegative matrices with several interesting properties. In this article, we introduce a wider class of matrices called generalized Euclidean distance matrices (GDMs) that include EDMs. Each…

Functional Analysis · Mathematics 2021-08-20 R. Balaji , R. B. Bapat , Shivani Goel

We prove a sharp upper bound on the number of distinct columns of a totally unimodular matrix with column sums $1$ improving upon Heller's classical bound. The proof uses Seymour's decomposition theorem. Such matrices are closely related to…

Combinatorics · Mathematics 2026-04-14 Benjamin Nill

In this paper, we give upper bounds on the sizes of $(d, L)$ list-decodable codes in the Hamming metric space from covering codes with the covering radius smaller than or equal to $d$. When the list size $L$ is $1$, this gives many new…

Information Theory · Computer Science 2023-01-25 Hao Chen , Longjiang Qu , Chengju Li , Shanxiang Lyu , Liqing Xu

Let $G$ denote the unramified quasi-split unitary group $\mathbb{U}(1,1)(F)$ over a $p$-adic field $F$ with residual characteristic $p \neq 2$. In this paper, we first construct a large family of irreducible representations of the maximal…

Representation Theory · Mathematics 2025-11-11 Ekta Tiwari

An undirected graphical model is a joint probability distribution defined on an undirected graph G*, where the vertices in the graph index a collection of random variables and the edges encode conditional independence relationships among…

Machine Learning · Statistics 2013-12-03 Divyanshu Vats , Robert Nowak

A unitary design is a collection of unitary matrices that approximate the entire unitary group, much like a spherical design approximates the entire unit sphere. In this paper, we use irreducible representations of the unitary group to find…

Combinatorics · Mathematics 2009-08-31 Aidan Roy , A. J. Scott

We extend an earlier result by Dan Abramovich, showing that a conjecture of S. Lang's implies the existence of a uniform bound on the number of $K$-rational points over all smooth curves of genus $g$ defined over $K$, where $K$ is any…

alg-geom · Mathematics 2008-02-03 Patricia L. Pacelli

A matrix $H=[d_{ij}]$ is a generalized Hadamard matrix of order $u\lambda$ with entries from $U$ which is a finite group of order $u$ (for short $\mathrm{GH}(u,\,\lambda)$) such that whenever $i\neq \ell$ the set $\{d_{ij}d_{\ell…

Combinatorics · Mathematics 2013-09-10 Hiroaki Kido

Based on work presented in [4], we define $S^2$-Upper Triangular Matrices and $S^2$-Lower Triangular Matrices, two special types of $d\times d(2d-1)$ matrices generalizing Upper and Lower Triangular Matrices, respectively. Then, we show…

Rings and Algebras · Mathematics 2023-10-03 Steven R. Lippold

The ranks and kernels of generalized Hadamard matrices are studied. It is proven that any generalized Hadamard matrix $H(q,\lambda)$ over $F_q$, $q>3$, or $q=3$ and $\gcd(3,\lambda)\not =1$, generates a self-orthogonal code. This result…

Information Theory · Computer Science 2016-11-15 Steven T. Dougherty , Josep Rifà , Mercè Villanueva

Generalized diagonal matrices are matrices that have two ladders of entries that are zero in the upper right and bottom left corners. The minors of generic generalized diagonal matrices have square-free initial ideals. We give a description…

Commutative Algebra · Mathematics 2022-06-06 Vinh Nguyen , Hunter Simper

As part of the graph minor project, Robertson and Seymour showed in 1990 that the class of graphs that can be embedded in a given surface can be characterized by a finite set of minimal excluded minors. However, their proof, because…

Combinatorics · Mathematics 2026-04-06 Sarah Houdaigoui , Ken-ichi Kawarabayashi

In the present paper we introduce a notion of $G-$decompositions of matrices. Main result of the paper is that a symmetric matrix $A_m$ has a $G-$decomposition in the class of stochastic (resp. substochastic) matrices if and only if $A_m$…

Combinatorics · Mathematics 2015-02-10 Rasul Ganikhodjaev , Farrukh Mukhamedov , Mansoor Saburov

A universal adjacency matrix of a graph $G$ with adjacency matrix $A$ is any matrix of the form $U = \alpha A + \beta I + \gamma J + \delta D$ with $\alpha \neq 0$, where $I$ is the identity matrix, $J$ is the all-ones matrix and $D$ is the…

Combinatorics · Mathematics 2020-04-07 Willem H. Haemers , Mohammad Reza Oboudi

We consider the problem of deciding if a set of quantum one-qudit gates $\mathcal{S}=\{g_1,\ldots,g_n\}\subset G$ is universal, i.e if the closure $\overline{<\mathcal{S}>}$ is equal to $G$, where $G$ is either the special unitary or the…

Quantum Physics · Physics 2017-11-07 Adam Sawicki , Katarzyna Karnas

A real symmetric matrix $M$ is completely positive semidefinite if it admits a Gram representation by (Hermitian) positive semidefinite matrices of any size $d$. The smallest such $d$ is called the (complex) completely positive semidefinite…

Optimization and Control · Mathematics 2016-10-27 Sander Gribling , David de Laat , Monique Laurent

Let $\Mg$ denote the moduli space of compact Riemann surfaces of genus $g$. Mumford had proved that, for each fixed genus $g$, there are isomorphisms asserting that certain higher $DET$ bundles over $\Mg$ are certain fixed…

alg-geom · Mathematics 2008-02-03 Indranil Biswas , Subhashis Nag , Dennis Sullivan
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