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In this paper we consider binary linear codes spanned by incidence matrices of Steiner 2-designs associated with maximal arcs in projective planes of even order, and their dual codes. Upper and lower bounds on the 2-rank of the incidence…

Combinatorics · Mathematics 2020-03-06 Mustafa Gezek , Rudi Mathon , Vladimir D. Tonchev

Let $K$ be a field and let $V$ be a vector space of dimension $n$ over $K$. Let $M$ be a subspace of bilinear forms defined on $V\times V$. Let $r$ be the number of different non-zero ranks that occur among the elements of $M$. Our aim is…

Rings and Algebras · Mathematics 2018-01-24 Rod Gow

In this paper we prove new lower bounds for the maximal size of permutation codes by connecting the theory of permutation codes with the theory of linear block codes. More specifically, using the columns of a parity check matrix of an…

Information Theory · Computer Science 2019-01-28 Giacomo Micheli , Alessandro Neri

A (q,k,t)-design matrix is an m x n matrix whose pattern of zeros/non-zeros satisfies the following design-like condition: each row has at most q non-zeros, each column has at least k non-zeros and the supports of every two columns…

Combinatorics · Mathematics 2011-03-11 Boaz Barak , Zeev Dvir , Avi Wigderson , Amir Yehudayoff

In this note we prove two extensions of a recent combinatorial characterization due to Li, Qiao, Wigderson, Wigderson and Zhang (arXiv:2206.04815) of the maximal dimension of bounded rank subspaces of the graphical matrix space associated…

Combinatorics · Mathematics 2023-10-30 Alexander Guterman , Roy Meshulam , Igor Spiridonov

The linkage construction and its generalization is one of the most powerful constructions for constant dimension code, accounting for approximately 50\% of all the listed parameters. We show how to improve the linkage construction of…

Information Theory · Computer Science 2020-05-12 Xianmang He

Inspired by the work of Zhou "On equivalence of maximum additive symmetric rank-distance codes" (2020) based on the paper of Schmidt "Symmetric bilinear forms over finite fields with applications to coding theory" (2015), we investigate the…

Combinatorics · Mathematics 2020-08-14 Rocco Trombetti , Ferdinando Zullo

In the context of constant--dimension subspace codes, an important problem is to determine the largest possible size $A_q(n, d; k)$ of codes whose codewords are $k$-subspaces of $\mathbb{F}_q^n$ with minimum subspace distance $d$. Here in…

Combinatorics · Mathematics 2021-11-22 Antonio Cossidente , Sascha Kurz , Giuseppe Marino , Francesco Pavese

Let $X=X(n,q)$ be the set of $n\times n$ Hermitian matrices over $\mathbb{F}_{q^2}$. It is well known that $X$ gives rise to a metric translation association scheme whose classes are induced by the rank metric. We study $d$-codes in this…

Combinatorics · Mathematics 2017-08-18 Kai-Uwe Schmidt

We show that large subsets of vector spaces over finite fields determine certain point configurations with prescribed distance structure. More specifically, we consider the complete graph with vertices as the points of $A \subseteq…

Combinatorics · Mathematics 2018-02-20 Alex Iosevich , Hans Parshall

In this paper we investigate connections between linear sets and subspaces of linear maps. We give a geometric interpretation of the results of [18, Section 5] on linear sets on a projective line. We extend this to linear sets in arbitrary…

Combinatorics · Mathematics 2018-06-18 John Sheekey , Geertrui Van de Voorde

We investigate the maximum cardinality and the mathematical structure of error-correcting codes endowed with the Kendall-$\tau$ metric. We establish an averaging bound for the cardinality of a code with prescribed minimum distance, discuss…

Combinatorics · Mathematics 2024-05-24 Benjamin Jany , Alberto Ravagnani

In the context of error control in random linear network coding, it is useful to construct codes that comprise well-separated collections of subspaces of a vector space over a finite field. In this paper, the metric used is the so-called…

Information Theory · Computer Science 2009-04-08 Azadeh Khaleghi , Frank R. Kschischang

In the last decade there has been a great interest in extending results for codes equipped with the Hamming metric to analogous results for codes endowed with the rank metric. This work follows this thread of research and studies the…

Information Theory · Computer Science 2020-01-22 Paulo Almeida , Umberto Martínez-Penas , Diego Napp

For any admissible value of the parameters there exist Maximum Rank distance (shortly MRD) $\mathbb{F}_{q^n}$-linear codes of $\mathbb{F}_q^{n\times n}$. It has been shown in \cite{H-TNRR} (see also \cite{ByrneRavagnani}) that, if field…

Information Theory · Computer Science 2019-04-08 Luca Giuzzi , Ferdinando Zullo

A new construction for constant weight codes is presented. The codes are constructed from $k$-dimensional subspaces of the vector space $\F_q^n$. These subspaces form a constant dimension code in the Grassmannian space $\cG_q(n,k)$. Some of…

Information Theory · Computer Science 2015-03-14 Tuvi Etzion , Alexander Vardy

Consider $S$, a set of $n$ points chosen uniformly at random and independently from the unit hypercube of dimension $t>2$. Order $S$ by using the Cartesian product of the $t$ standard orders of $[0,1]$. We determine a constant $\bar x(t)<e$…

Combinatorics · Mathematics 2025-07-15 Boris Pittel

The application of flags to network coding has been introduced recently by Liebhold, Nebe, and Vazquez-Castro. It is a variant to random linear network coding and explicit routing solutions for given networks. Here we study lower and upper…

Combinatorics · Mathematics 2021-10-12 Sascha Kurz

Let $C$ be a linear code of length $n$ and dimension $k$ over the finite field $\mathbb{F}_{q^m}$. The trace code $\mathrm{Tr}(C)$ is a linear code of the same length $n$ over the subfield $\mathbb{F}_q$. The obvious upper bound for the…

Information Theory · Computer Science 2023-09-06 Márton Erdélyi , Pál Hegedüs , Sándor Z. Kiss , Gábor P. Nagy

Fedorchuk's fully closed (continuous) maps and resolutions are applied in constructions of non-metrizable higher-dimensional analogues of Anderson, Choquet, and Cook's continua. Certain theorems on dimension-lowering maps are proved for…

General Topology · Mathematics 2010-10-19 Jerzy Krzempek