Math and Cookies is an undergraduate research seminar and Department seminar is for math faculty members.
Math and Cookies and Department seminar will alternate each week.
These seminars are partly supported by NSF LEAPS-MPS (DMS-2532394).
If you are interested in giving a talk (or you know somebody), please let me know!
The following is the list of the speakers for the seminar for Spring 2026.
We meet: Wednesdays 1:00 pm - 2:00 pm at OM130
Feb 11: Daniel Corey (Embry-Riddle Aeronautical University)
Title: Point configurations and matroids
Abstract: Point configurations are a classical object of study in mathematics, dating back to early work in projective geometry and combinatorics. Roughly speaking, a point configuration is a collection of points in an ambient (often projective) space together with information about which subsets of points are collinear or linearly independent. The combinatorial data underlying these dependence relations is encoded by a structure called a matroid. Matroid theory is an area that is seeing much development in recent years, especially in connection to algebraic geometry. In this talk, I will explain what a matroid is from this perspective. We will explore the geometry that arises when we fix a matroid and consider all point configurations that realize it. This leads to the notion of a realization space, which can be described using systems of polynomial equations and inequalities. The fundamental result in this area is Mnëv’s universality theorem, which shows that realization spaces satisfy “Murphy’s Law” in that every singularity type can occur. I will conclude by presenting the smallest explicit example of a matroid whose realization space is singular, which was found in joint with Dante Luber.
Feb 18: Jose David Beltran Lizarazo (The University of Iowa)
Title: Formation of singularities in nonlinear conservation laws
Abstract: In this talk, we will illustrate the formation of singularities in classical solutions to some nonlinear conservation laws in one space dimension. Using elementary tools from calculus we show that, even when the initial data is smooth, classical solutions break down in finite time, and first order derivatives blow up. We will discuss some of the physical interpretations of these singularities together with the challenges that this phenomenon imposes in the analysis of nonlinear conservation laws. Finally, we introduce some strategies to study the existence of solutions for these kind of problems.
Feb 25: Tong Jin (Vanderbilt)
Title: Homotopy theory in matroid representations
Abstract: Matroids are combinatorial abstracts of independence, a notion that appears in graph theory, linear algebra, and field extensions. In this talk, we will discuss Tutte's homotopy theory, which, roughly speaking in a modern language, asserts that the first homology of a certain 2-dimensional complex associated to the matroid M is always trivial. Tutte's homotopy theory has nice consequences in matroid representation theory and excluded minor problems, and we will see connections between the three. If time permits, I'll also talk about some recent progress on generalizations to other Coxeter types of matroids.
Mar 4: Kalina Mincheva (Tulane University)
Title: The Tropical Coordinate Semiring
Abstract: Tropical geometry provides a new set of purely combinatorial tools, which has been used to approach classical problems. In tropical geometry most algebraic computations are done on the classical side - using the algebra of the original variety. The theory developed so far has explored the geometric aspect of tropical varieties as opposed to the underlying (semiring) algebra and there are still many commutative algebra tools and notions without a tropical analogue. In the recent years, there has been a lot of effort dedicated to developing the necessary tools for commutative algebra using different frameworks, among which prime congruences, tropical ideals, tropical schemes. These approaches allows for the exploration of the properties of tropicalized spaces without tying them up to the original varieties and working with geometric structures inherently defined in characteristic one (that is, additively idempotent) semifields. In this talk we will describe the `coordinate semiring' of a tropical variety, what information it carries, its integral closure, and some examples of normalization in tropical geometry.
Mar 5 (Thursday): We have two speakers (NOTE: Special Date and Time and Location).
Dongeun Kim (Assumption University), 2:00 pm - 3:00 pm at OM237
Title: Influence of Contagious Diseases on Consumers’ Natural Preference
Abstract: It is well-established that consumers have a strong preference for natural products. For instance, consumers typically prefer non-genetically modified foods over their genetically modified counterparts, despite the fact that the latter is often cheaper. Across one empirical study and three experiments, the current research shows that this preference for naturalness can be shifted when contagious disease cues are salient. Indeed, when these cues are salient, consumers no longer prefer natural options over less natural counterparts to a significant degree. The mechanism driving this effect is consumers’ heightened distrust of natural goods. Importantly, while this reduced natural preference occurs when contagious disease cues are salient, this effect does not occur when non-contagious cues are salient; this distinction suggests that contagious disease cues may be perceived as an inherent threat from nature to consumers. This research offers insight into the underlying process behind the natural preference. In addition, this research provides marketing implications suggesting that consumers may be more willing to accept less natural products in the presence of contagious disease cues.
Seung-Wook Kim (Bentley University), 3:00 pm - 4:00 pm at OM237
Title: The Psychological Distance Discount Phenomenon in Entertainment Products: Evidence from U.S. Movies between Their Domestic and Foreign Markets
Abstract: Entertainment products are not always well received outside their country of origin, often due to cultural discount. We broaden the scope of cultural discount by examining the four dimensions of Psychological Distance (PD): (1) Person (Social Distance), (2) Hypotheticality, (3) Space, and (4) Time. We theorize that when an entertainment product is presented in a non-home country, consumers are likely to exhibit a Psychological Distance Discount (PDD), because they do not fully appreciate the psychological connotations of products from other nations. We posit that PDD will manifest in Person and Hypotheticality (the more complex, psychologically sensitive dimensions), whereas consumers’ understanding of Space and Time (the simpler, less psychologically sensitive dimensions) will not vary substantially across nations. In our empirical test, we examine how Koreans respond to U.S. movies differently from Americans. Our analysis shows that certain marketing variables—production budget and the number of screens—can mitigate the negative effects of PDD in the Korean movie market, owing to Korea’s stronger social network effect.
Mar 11: Youngsu Kim (California State University San Bernardino)
Title: Wegner’s 8-Color Theorem Revisited
Abstract: Graph coloring is a fundamental and intriguing area in graph theory. The Four-Color Theorem asserts that any planar graph can be colored using at most four colors. In 1977, Wegner proposed a set of conjectures concerning the chromatic number of the square of a graph. A distance-2 coloring is one in which any two vertices at distance one or two must receive distinct colors.
In particular, he conjectured that every planar graph of maximum degree at most three admits a distance-2 coloring with at most seven colors, and proved that eight colors always suffice. The 7-color case was settled in 2016 by Hartke, Jahanbekam, and Thomas, and independently by Thomassen.
In this talk, we present a new proof of Wegner’s 8-color theorem. We believe our approach is more streamlined and intuitive, as it eliminates the need for case-checking arguments in Wegner’s original proof. This is joint work with Hajrudin Fejzić and Gabriel Elvin.
Mar 18: Timothy Susse (industry, Link to Linked in)
Title: Random Graphs, Random Groups
Abstract: We will discuss the deep connections between the theory of random graphs and the theory of random groups. We begin by introducing the family of right-angled Coxeter groups (RACGs), a family parameterized by simple graphs. Exploring the connections between the graph structure and group structure in this family, we ask “what does a typical RACG look like?” Using the Erdos-Renyi random graph model, we give answers for a variety of geometric properties. This talk covers joint work with Jason Behrstock, Victor Falgas-Ravry and Mark Hagen.
Apr 15: Sookkyoung Lim (University of Cincinnati) (Talk cancelled and rescheduled to Fall 2026).
Apr 29: Hyunsun Lee (Brigham Women’s Hospital, Harvard Medical School, and University of Massachusetts Amherst)
Title:
Abstract: