I have been part of the math
department at the University of Western Ontario since 2002. I
received my PhD at the University
of Michigan in 1999. In 201819, I am the Acting Chair of the
Department of Mathematics.
Research
My mathematical interests fit roughly under a heading of algebraic
combinatorics. More precisely, this includes arrangements of
hyperplanes and subspaces, combinatorial aspects of rational homotopy
theory, and "toric topology."
I have some preprints and publications available here.
Teaching
Winter 2019:
Other Activities
The mathematics colloquium:
Scheduled events for 201718 are listed
here.
Conference and workshop organization:
Upcoming events:
Past events:
 Arrangements
of Hypersurfaces, a oneday workshop (April 20th 2018) and an AMS special session at the 2018 Spring Eastern
Meeting, April 2122, 2018, Northeastern University, Boston, MA. Coorganized
with Alex Suciu.

Topology of
Arrangements and Representation Stability, Oberwolfach, 1420
January 2018, coorganized with Giovanni Gaiffi (Pisa), Rita Jimenez
Rolland (Oaxaca), and
Alex Suciu (Boston).
 CAAC 2016, Western, 2224 January
2016, coorganized with Nicole
Lemire
(Western) and Hugh Thomas (UQAM), a threeday meeting in algebraic
combinatorics and its interactions with algebraic geometry and
commutative algebra. (The abstracts
page has slides from some of the talks.)
 Combinatorial
Constructions in Topology, University of Regina, August 1721,
2015, coorganized
with Soumen Sarkar, Don Stanley (U. Regina) and Alex Suciu
(Northeastern University). See the abstracts page for slides
from some of the talks.
 Differential
and Combinatorial Aspects of Singularities, TU Kaiserslautern,
coorganized with Mathias
Schulze, Christian
Sevenheck, Uli
Walther, August 37, 2015. See the abstracts page for the slides
from some of the talks.
 Computational
Geometric Topology in Arrangement Theory, ICERM (Providence, RI),
July 610, 2015, with Nero Budur, Dani Matei, Laurentiu Maxim, Hal
Schenck, and Max Wakefield.
 A focussed research group
Hyperplane Arrangements, Wonderful Compactifications, and
Tropicalization
at BIRS, with June
Huh
and Alex Suciu,
April 2014.
 Cohomology
Rings and
Fundamental Groups of Hyperplane Arrangements, Wonderful
Compactifications, and Real Toric Varieties at the Mathematisches
Forschungsinstitut Oberwolfach, with Alex Suciu, October
2012.
 An AMS special session "The Algebraic Geometry
and
Topology of
Hyperplane Arrangements" at the AMS
spring sectional meeting in Worcester, MA, April 910, 2011,
preceded by
a workshop at Northeastern University on April 8, with Alex Suciu.
 A Conference
in Honour of Peter Orlik at the Fields Institute in Toronto,
with Dan Cohen
and Nicole Lemire,
August 2008.
I am a fan of Macaulay
2 (software for commutative algebra and algebraic geometry). Greg Smith
and I have written a package for computation with hyperplane
arrangements. It is included with the standard Macaulay 2
distribution (versions ≥ 1.0).
I was on sabbatical from July 2016  June 2017: I visited the University of Sydney from January through April, and ALTA at the University of Bremen from May through July. During my previous sabbatical in 200910, I visited
the EPFL (Lausanne) from September
through November, and the University
of
Oregon from January through summer 2010.