Chip-Firing Games and Graph Gonality by Prof. Ralph Morrison

Chip-Firing Games and Graph Gonality by Prof. Ralph Morrison, Mathematics Colloquium, Wednesday, June 21, 1 – 1:50 pm, North Science Building 113, Wachenheim.

Abstract:  We place poker chips on a graph, and slide them around according to certain chip-firing rules.  We then ask:  how many chips do we have to place on a graph so that we can move a chip to any vertex we like, without any other vertex being in debt?  The minimum possible number of chips to achieve this goal is called the gonality of the graph, which is an important and difficult invariant to study.  We’ll talk about how to find upper and lower bounds on gonality, and about how gonality can change as we modify our graph.