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We say that a diagonal in an array is {\em $\lambda$-balanced} if each entry occurs $\lambda$ times. Let $L$ be a frequency square of type $F(n;\lambda^m)$; that is, an $n\times n$ array in which each entry from $\{1,2,\dots ,m\}$ occurs…

Combinatorics · Mathematics 2018-02-06 Nicholas Cavenagh , Adam Mammoliti

In 1975, Stein made a wide generalisation of the Ryser-Brualdi-Stein conjecture on transversals in Latin squares, conjecturing that every equi-$n$-square (an $n\times n$ array filled with $n$ symbols where each symbol appears exactly $n$…

Combinatorics · Mathematics 2024-12-11 Debsoumya Chakraborti , Micha Christoph , Zach Hunter , Richard Montgomery , Teo Petrov

Gy\'{a}rf\'{a}s and S\'{a}rk\"{o}zy conjectured that every $n\times n$ Latin square has a `cycle-free' partial transversal of size $n-2$. We confirm this conjecture in a strong sense for almost all Latin squares, by showing that as $n…

Combinatorics · Mathematics 2022-04-12 Stephen Gould , Tom Kelly

A latin square of order $n$ with pairwise disjoint subsquares of orders $h_1,\dots,h_k$ such that $h_1+\dots+h_k = n$ is known as a realization. The existence of realizations is a partially solved problem with a few general results for an…

Combinatorics · Mathematics 2026-03-26 Tara Kemp

We investigate MacNeish's conjecture (known to be false in general) in the setting of what we call "transitive" Mutually Orthogonal Latin Squares (MOLS). When we restrict our attention to "simply transitive" MOLS, we find that the…

Combinatorics · Mathematics 2026-02-02 Amadou Keita , Ilya Shapiro

In this paper we study pattern avoidance in Latin Squares, which gives us a two dimensional analogue of the well studied notion of pattern avoidance in permutations. Our main results include enumerating and characterizing the Latin Squares…

Combinatorics · Mathematics 2014-03-11 Michael J. Earnest , Samuel C. Gutekunst

Let $m \leq n \leq k$. An $m \times n \times k$ 0-1 array is a Latin box if it contains exactly $mn$ ones, and has at most one $1$ in each line. As a special case, Latin boxes in which $m = n = k$ are equivalent to Latin squares. Let…

Combinatorics · Mathematics 2019-02-12 Zur Luria , Michael Simkin

A quantum Latin square of order $n$ (denoted as QLS$(n)$) is an $n\times n$ array whose entries are unit column vectors from the $n$-dimensional Hilbert space $\mathcal{H}_n$, such that each row and column forms an orthonormal basis. Two…

Quantum Physics · Physics 2026-01-15 Ying Zhang , Lijun Ji

A Latin square of order $n$ is an $n \times n$ matrix of $n$ symbols, such that each symbol occurs exactly once in each row and column. For an odd prime power $q$ let $\mathbb{F}_q$ denote the finite field of order $q$. A quadratic Latin…

Combinatorics · Mathematics 2023-07-18 Jack Allsop

In 2008, Cavenagh and Dr\'{a}pal, et al, described a method of constructing Latin trades using groups. The Latin trades that arise from this construction are entry-transitive (that is, there always exists an autoparatopism of the Latin…

Combinatorics · Mathematics 2023-08-30 Nicholas Cavenagh , Raúl Falcón

To any $n \times n$ Latin square $L$, we may associate a unique sequence of mutually orthogonal permutation matrices $P = P_1, P_2, ..., P_n$ such that $L = L(P) = \sum kP_k$. Brualdi and Dahl (2018) described a generalisation of a Latin…

Combinatorics · Mathematics 2020-08-18 Cian O'Brien

We investigate retransmission permutation arrays (RPAs) that are motivated by applications in overlapping channel transmissions. An RPA is an $n\times n$ array in which each row is a permutation of ${1, ..., n}$, and for $1\leq i\leq n$,…

Combinatorics · Mathematics 2015-05-05 Ian M. Wanless , Xiande Zhang

Latin tableaux are a generalization of Latin squares, which first appeared in the early 2000's in a paper of Chow, Fan, Goemans, and Vondr\'{a}k. Here, we extend the notion of isotopy, a permutation group action, from Latin squares to Latin…

Combinatorics · Mathematics 2021-04-02 R. Karpman , É. Roldán

This is a companion note to the paper "Almost all Steiner triple systems have perfect matchings (arXiv:1611.02246). That paper contains several general lemmas about random Steiner triple systems; in this note we record analogues of these…

Combinatorics · Mathematics 2021-10-01 Matthew Kwan , Ashwin Sah , Mehtaab Sawhney

The problem of completing a partially specified n by n Latin square is solved by an alternative proof, based on filling the rows (or diagonals) from 1 to n, using an extended form of Hall's marriage theorem.

Combinatorics · Mathematics 2016-12-28 Eli Shamir

We show that any partial Latin square of order $n$ can be embedded in a Latin square of order at most $16n^2$ which has at least $2n$ mutually orthogonal mates. We also show that for any $t\geq 2$, a pair of orthogonal partial Latin squares…

Combinatorics · Mathematics 2018-11-13 Diane M. Donovan , Mike Grannell , Emine Şule Yazıcı

To study orthogonal arrays and signed orthogonal arrays, Ray-Chaudhuri and Singhi (1988 and 1994) considered some module spaces. Here, using a linear algebraic approach we define an inclusion matrix and find its rank. In the special case of…

Combinatorics · Mathematics 2009-05-05 A. A. Khanban , M. Mahdian , E. S. Mahmoodian

An $n$-ary quasigroup $f$ of order $q$ is an $n$-ary operation over a set of cardinality $q$ such that the Cayley table of the operation is an $n$-dimensional latin hypercube of order $q$. A transversal in a quasigroup $f$ (or in the…

Combinatorics · Mathematics 2017-09-12 Anna Taranenko

A Latin square is reduced if its first row and column are in natural order. For Latin squares of a particular order $n$ there are four possible different parities. We confirm a conjecture of Stones and Wanless by showing asymptotic equality…

Combinatorics · Mathematics 2016-10-21 Nicholas J. Cavenagh , Ian M. Wanless

A latin bitrade is a pair of partial latin squares which are disjoint, occupy the same set of non-empty cells, and whose corresponding rows and columns contain the same set of entries. Dr\'apal (\cite{Dr9}) showed that a latin bitrade is…

Combinatorics · Mathematics 2008-03-08 Nicholas J. Cavenagh , Ales Drapal , Carlo Hamalainen