collaborators

6 papers

math.CO2026

Complex generalised weighing matrices in centraliser algebras of monomial representations

Ronan Egan, Padraig Ó Catháin, Andrea Švob

An matrix with exactly non-zero entries taken from the set of complex roots of unity in each row and column satisfying is a com…

math.CO2026

Cliques in graphs constructed from Strongly Orthogonal Subsets in exceptional root systems

Patrick J. Browne, Pádraig Ó Catháin

Given a root system , two roots are said to be \emph{strongly orthogonal} if neither their sum nor difference is a root. Gashi defined a family of graphs with vertices labelled…

math.CO2026

Symmetries of regular -graphs

Daniel R Hawtin, Padraig Ó Catháin

Given a finite vector space , the -analogue of a graph, called a -graph, is a pair , where is the set of -dim…

math.CO2025

A generalisation of bent vectors for Butson Hadamard matrices

José Andrés Armario, Ronan Egan, Hadi Kharaghani +1

An complex matrix with entries in the roots of unity which satisfies is called a Butson Hadamard matrix. While a matrix with…

math.CO2025

Centraliser algebras of monomial representations and applications in combinatorics

Santiago Barrera Acevedo, Padraig Ó Catháin, Heiko Dietrich +1

Centraliser algebras of monomial representations of finite groups may be constructed and studied using methods similar to those employed in the study of permutation groups. Guided…

math.CO2025

Extendibility of Latin Hypercuboids

Candida Bowtell, Alice Devillers, André Kündgen +2

A Latin hypercuboid of order is a -dimensional matrix of dimensions , with symbols from a set of cardinality such that each symbol…