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This conference is meant to be a celebration of the scholarship of the late David A. Gregory, a long-serving Professor in the Department of Mathematics at Queen's University. David Gregory explored mathematical problems that bridged two areas of mathematics: linear algebra and discrete mathematics, especially graph theory. His insights, careful approach and writing influenced many mathematicians, especially in combinatorial matrix theory.

David's research was initially focused upon vector sequence spaces but moved into topics related to ranks, exploring Boolean rank, nonnegative rank, and even introducing a new concept, Hermitian rank. He explored algebraic connections with some graph theoretic counting problems, like finding bounds on clique cover numbers, biclique partitions, and multiclique decompositions of graphs. He was fond of exploring variations on the Graham-Pollak theorem, a result which solves a purely combinatorial problem via clever algebraic means. Following along these lines, David has been keenly interested in eigenvalues of graphs and tournaments, exploring connections to inertia of graphs, spread of the eigenvalues of a graph, and most recently, relationships between eigenvalues and the size of matchings of a graph, or the independence number.

David Gregory made many contributions to these topics. The goal of the conference is to spend some time reflecting on David's contributions, to gather researchers who have collaborated with David (of which there are many), as well as other researchers who have been influenced by his work, to explore recent developments, and to make new or stronger connections in the research community. The conference will be of interest to the linear algebra community, especially those in combinatorial matrix theory, but researchers representing any aspect of David Gregory's mathematical scholarship are invited to attend and propose a presentation.

Further, some colleagues who have worked closely with David are preparing a manuscript which surveys the scholarship of David Gregory and presents open problems that he has proposed. David left some very interesting open problems that are of interest to the wider linear algebra and discrete mathematics communities.