Talks

Here are the slides for some of the talks I have given:

Creating Pathways to Math Success at a Liberal Arts College: This talk is about the changes Lauren Rose and I made at Bard College to help students succeed in introductory math courses. I gave this talk at the AMS-MAA Joint Meetings in 2012.
Abstract: Bard College is a liberal arts college with close to 2000 students. While many of our students enter college ready for calculus, we also have some students who need to start with precalculus, and some students who would have difficulty in a precalculus course. In the past few years, we have made several changes to help these students succeed in their math courses and to create a pathway for students with weak backgrounds to major in math and science. We added a Math Placement Exam as a way to identify students in need, we created an evening Math Study Room staffed by peer tutors, and we added two 2-credit algebra review courses for students who want to improve their algebra or precalculus skills. In this talk, we will go over the details of these changes, and discuss our impressions of how these changes have helped students to succeed in their math and science courses.

Realizability of Graphs: This is the talk I gave at Discrete Math Day at Bard College in November 2008.
Abstract: A graph is d-realizable if, for every realization of the graph in some Euclidean space, there exists a realization in d-dimensional Euclidean space with the same edge lengths. For example, any tree is 1-realizable, but a triangle is not. In this talk, we will classify all 3-realizable graphs. This talk is based on joint research with Robert Connelly.

Realizability of Graphs: This is a version of the above talk that was aimed at undergraduates attending the Carleton Summer Math Program during the summer of 2007.

Making Your House Safe from Zombie Attacks: I gave this talk at the AMS-MAA Joint Meetings in January 2008.
Abstract: We investigate the important question of how many zombies are required to catch and eat a person in an enclosed structure. We model the structure with a graph, and we assume that the person can move much faster than the zombies. The minimum number of zombies required to catch an intelligent person is called the zombie number of the graph. This is a variation on the "cops and robbers" game from graph theory, which can be used to define the treewidth of a graph. In this talk, we will discuss how the zombie number of a graph relates to the treewidth, and we will investigate forbidden minors for zombie number n. This talk will assume no prior knowledge of graph theory, and should be accessible to undergraduates. This talk is based on ongoing research with Jim Belk.

Problems related to the Kneser-Poulsen Conjecture: I gave this talk in Fall 2007 in the Algebra and Combinatorics seminar at Texas A&M.
Abstract: Consider a collection of overlapping balls in Euclidean space. If we change the positions of the balls, then the volume of the union may change. In the 1950's, Kneser and Poulsen conjectured that if the distances between the centers do not decrease, then the volume of the union must increase or remain the same. In 2002, Bezdek and Connelly proved this conjecture for discs on the Euclidean plane. The conjecture remains open for higher dimensional Euclidean spaces, as well as for spherical and hyperbolic spaces. In this talk, we will examine the difficulties involved in extending the proof to these other settings.