Eric Swartz

activity

20172020

collaborators

5 papers

math.RA2020

Covering numbers of commutative rings

Eric Swartz, Nicholas J. Werner

A cover of a unital, associative (not necessarily commutative) ring $R$ is a collection of proper subrings of $R$ whose set-theoretic union equals $R$ . If such a cover exists, then…

math.CO2020

Restrictions on parameters of partial difference sets in nonabelian groups

Eric Swartz, Gabrielle Tauscheck

A partial difference set $S$ in a finite group $G$ satisfying $1 \in / S$ and $S = S^{- 1}$ corresponds to an undirected strongly regular Cayley graph $Cay (G, S)$ . While the c…

math.CO2019

Homomorphisms of matrix algebras and constructions of Butson-Hadamard matrices

Padraig O Cathain, Eric Swartz

An $n \times n$ matrix $H$ is Butson-Hadamard if its entries are $k^{th}$ roots of unity and it satisfies $H H^{*} = n I_{n}$ . Write $B H (n, k)$ for the set of such matrices. Suppo…

math.GR2019

A classification of finite locally 2-transitive generalized quadrangles

John Bamberg, Cai Heng Li, Eric Swartz

Ostrom and Wagner (1959) proved that if the automorphism group $G$ of a finite projective plane $π$ acts $2$ -transitively on the points of $π$ , then $π$ is isomorphic to the Desarg…

cs.IT2017

Improved User-Private Information Retrieval via Finite Geometry

Oliver Gnilke, Marcus Greferath, Camilla Hollanti +3

In a User-Private Information Retrieval (UPIR) scheme, a set of users collaborate to retrieve files from a database without revealing to observers which participant in the scheme r…