April 20, 2014

June 20-21,2014
Conference on Graph Theory, Matrix Theory and Interactions

A Conference to celebrate the scholarship of David Gregory
Queen's University

Organizing Committee
Sebastian Cioaba, Bryan Shader, Ram Murty,
Claude Tardif, Kevin Vander Meulen, David Wehlau

Conference Summary

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.

Publications of David Gregory

Please contact any committee member if you wish to attend and/or present, or to receive further information.

Dedicated Journal Issue

A special issue of the Electronic Journal of Linear Algebra will be dedicated to David Gregory. Details forthcoming.

Local Accommodation

A block of rooms has been set aside on a first-come first-serve basis at the Donald Gordon Centre.

Rooms at the Donald Gordon Centre are reserved for Friday June 20 and Saturday June 21 (there is awaiting list for Thursday June 19).

Online Reservation:
Group Code: 134830 PIN 200614
or call 1-866-455-2655
Rate: $130 Cdn plus taxes/night – including on-site parking
Location: 20 minute walk to lecture room.
Cut-off-date: June 1st, 2014.
Name of booking: David Gregory Conference


A block of suites has been set aside on a first-come first-serve basis at Leggett/Watts Hall. The suites include two rooms with a bathroom in between. Participants may make there own arrangement to share a suite to save costs, otherwise they have the whole suite to themselves. These suites are reserved for Thursday June 19 and Friday June 20. If an additional night is desired, e.g. staying a third night June 21, then please indicate so in the notes section of
the online booking.

Online Reservation:
 Group Code:    25751
  or call   613-533-2223
 Rate: $99 Cdn plus taxes/night – parking extra
Location: 5 minute walk to lecture room.
Cut-off-date: June 1st, 2014
Name of booking: David Gregory Conference

Participants as of March 27, 2014

Full Name University/Affiliation
Brualdi, Richard A. University of Wisconsin - Madison
Cioaba, Sebastian University of Delaware
Elzinga, Randall Royal Military College
Fallat, Shaun

[The Hans Schneider ILAS Lecturer]
University of Regina

Godsil, Chris University of Waterloo
Haemers, Willem Tilburg university
Kirkland, Steve University of Manitoba
Lemay, Joel University of Ottawa
Mollahajiaghaei, Mohsen The University of Western Ontario
Murty, Ram Queen's University
Shader, Bryan University of Wyoming
Shaked-Monderer, Naomi The Max Stern Yezreel Valley College
Shibesh, Abraham kulleuven
Tardif, Claude Royal Military College of Canada
van Dam, Edwin Tillburg University
Vander Meulen, Kevin Redeemer University College
Wehlau, David Queen's University