My research interests fall into three broad areas:

although all three are linked. I've also worked on topics including coding theory, hypergraphs, matroids, enumeration, and combinatorial matrix theory.

My favourite mathematical topic is distance-regular graphs. Along with some student research assistants, I have developed, an online catalogue of distance-regular graphs, with graphs available to be downloaded for use in computations. This work led to some interesting new observations and is the subject of ongoing research.

A lot of my time has been devoted to the relationship between base sizes of permutation groups and the metric dimension of graphs. A survey article on this topic, with Peter Cameron, was published in the Bulletin of the London Mathematical Society in 2011. In particular, I've investigated the metric dimension of numerous families of distance-regular graphs.

In combinatorial design theory, my main contributions have focused on packing and covering versions of so-called "generalized t-designs", along with resolvability and block-colourings of designs.

Details of my publications are available here, or (if you have a subscription) MathSciNet. I also have a Google Scholar profile. Recent preprints are available on the arXiv.


Research funding

My research is funded by an NSERC Discovery Grant (2016–23), and has previously also been supported by a university start-up grant, and the university's "Seed, Bridge & Multidisciplinary Fund".


Students and Postdocs


Conferences attended

Travelling around the world (literally, on one occasion) to attend conferences and give talks is definitely one of the more enjoyable aspects of being a mathematician. A list of conferences I have attended (or may attend soon) is here.


Conferences organized

I was responsible for organizing, or co-organizing, the following conferences, workshops or conference sessions:


Erdős number

My Erdős number is 2, via the route Bailey–Cameron–Erdős. (For a long time, this was not mentioned in the Erdős Number Project's data, as they thought I was someone else....)