Harry Richman, Distinguishing graphs with tropical Weierstrass weights

I will introduce a new structure on finite graphs, which takes the form of a labeling of the vertices by nonnegative integers (possibly repeated). This labeling is isomorphism invariant, and seems to reflect some mix of local and global structure of the graph. I will describe an algorithm for computing these labels, which uses a form of breadth-first search, and some results on the resulting labels. This construction comes from a tropical analogue of Weierstrass weights on algebraic curves, studied in the 1800s. Finally, I will discuss some speculation on whether this may or may not be helpful for the graph isomorphism problem.

This is a joint work with Omid Amini and Lucas Gierczak.