Research
My work centers on combinatorial algebraic geometry, with a focus on the abelian sandpile model, chip-firing, and divisor theory on graphs.
- 2025Cycle systems, coparking functions, and h-vectors of matroids with S. Corry, A. Dochtermann, S. McClain, and L. Yi
- 2023Counting weighted maximal chains in the circular Bruhat order with G. Goel and O. McGough · Journal of Combinatorial Theory, Series A
- 2020Enumerating linear systems on graphs with S. Brauner and F. Glebe · Mathematische Zeitschrift
- 2018Divisors and Sandpiles with S. Corry · American Mathematical Society
- 2016Bigraphical arrangements with S. Hopkins · Transactions of the AMS
Projects
Divisors and Sandpiles
A textbook with Scott Corry, published by the AMS — an introduction to chip-firing and divisor theory on graphs.
Read →Sandpile simulation
An interactive WebGL sandpile explorer. Watch the identity element and other configurations emerge.
Launch →SageMath
Author of the sandpiles module and co-author of the hyperplane arrangements module.
Documentation →Teaching
Lecture notes from courses taught at Reed College, 1991–2024.
Students
Over three decades at Reed, I advised more than fifty senior theses on topics ranging from sandpile theory to tropical geometry to the mathematics of juggling.
Music
Concertina and fiddle duets with my daughter Joy, mbira recordings by my son Cole, and experiments in sandpile-generated music.