Colloquia - Spring 2025

If you are interested in giving a talk, please email Dr. Guillermo Alesandroni (galesandroni@csuchico.edu).

Colloquia are typically held on Friday in Holt 175. Please see below for specific information. Refreshments are served at 3:45 pm and the talk begins at 4:00 pm. Everyone is invited to attend!

Upcoming talk  

Friday, April 18 — Holt 175, 4:00pm

Catherine Cannizzo — UC Berkeley

Title: Mirror Geometries

Abstract: Given a symplectic manifold X, what is a mirror complex manifold Y? The concept of mirror symmetry is a duality between X and Y, inspired by string theory. In a 1994 ICM address, Maxim Kontsevich conjectured an algebraic version known as homological mirror symmetry. After a brief opening, I will introduce the conjecture and provide evidence it holds in several new examples.

Friday, April 25 — Holt 175, 4:00pm

Chris Barker — 

Title: TBA

Abstract: TBA

Past talks

Friday, April 11 — Holt 175, 3:00pm

Eoin MacKall — UC Santa Cruz

Title: A factorization algorithm based on Cohn’s irreducibility criterion

Abstract: Integer factorization is a simple problem to state with strong cryptographic applications.  The best known factorization methods involve interesting ideas from algebraic number theory and algebraic geometry.  After surveying some of the modern factorization techniques, I'll talk about a method to factor integers based on Cohn's irreducibility criterion. A basic algorithm from this factorization method has exponential running time in the worst case, which is not great, but I'll try to give reasons why this is still an interesting algorithm to think about nonetheless.

Friday, April 4 — Holt 175, 4:00pm

Carter Tillquist — CSU Chico

Title: Exploring Metric Dimension on Random Graphs

Abstract: The metric dimension of a graph G=(V,E) is the smallest number of nodes required to uniquely identify all nodes in G based on shortest path distances. This concept is closely related to trilateration, the idea underlying the Global Positioning System (GPS), and has applications in navigation and in generating embeddings for symbolic data analysis. In this talk, we discuss previous work and preliminary results related to the behavior of metric dimension in the context of Hamming graphs and several random graph models. Bounds on metric dimension and efficient heuristic algorithms for identifying close to optimal solutions are covered.

Friday, March 28 — Holt 175, 4:00pm

Sungjin Kim — CSU Northridge

Title: The probability that the Taylor resolution of a monomial ideal is minimal.

Abstract: Let k be an arbitrary field, and let k[X] be a polynomial ring on n variables. In this talk we express, in terms of Dedekind numbers, the probability that the Taylor resolution of a square- free monomial ideal of k[X] is minimal. We also show that this probability tends to 0 as n tends to ∞. For n ≤ 9, we compute the probability that the Taylor resolution is minimal, explicitly.

Friday, March 14 — Holt 175, 4:00pm

LaDawn Haws — CSU Chico

Title: In honor of Pi Day

Abstract: We will look at how pi was discovered, and some of the ways it can be approximated numerically.  After the historical treatment, we will see a few pi-related tidbits that should probably be described as recreational Mathematics.

Friday, February 28 — Holt 175, 4:00pm

Thomas Mattman — CSU Chico

Title: COVID on infinite grids

Abstract: (Joint with Barnett, Bond, Macias, Parnell, and Schoenfield) We use Hartnell’s model for virus spread on a graph. We propose a Containment Protocol which looks ahead two time steps to decide where to place vaccinations. We show that the protocol is near optimal for four well-studied infinite grids. We will ask the audience to help us find optimal solutions for a pentagonal grid. This talk will be accessible to all and we especially encourage students to join us.

Friday, February 21  — Holt 175, 4:00pm

Gabe Martins — CSU Sacramento

Title: Skateboard Tricks and Topological Flips

Abstract: We will discuss continuous deformations between different skateboard flip tricks, and we will see why up to deformation there are only four such tricks. That may be accomplished by describing the motion of skateboard flip tricks as continuous curves in the matrix group SO(3). We will also present animations and visualizations developed in Python for this project. Our strategy can be seen as a variant of Dirac's belt trick to a system with additional symmetries.

Friday, February 14 — Holt 175, 4:00pm

Puttipong Pongtanapaisan — Arizona State University

Title: Organizing the Space of Colorings of Knotted Objects

Abstract: Deciding whether one shape can be smoothly deformed into another is often challenging. A powerful approach to this problem involves coloring a diagram of a knotted shape according to algebraic rules that remain consistent under smooth deformations. In this talk, we introduce an invariant called the coloring quiver, which not only counts valid colorings but also tracks how different colorings relate to one another. This additional structure captures subtleties that the mere count of colorings (the coloring number) can miss. In particular, we present examples of knotted shapes with the same number of valid colorings that are nevertheless distinguished by their coloring quivers, illustrating that this new invariant is strictly stronger than the traditional coloring number.

Friday, January 31 — Holt 175, 4:00pm 

Rosemarie Bongers — UC Merced

Title: Transitions in a mathematical career

Abstract:  As an early graduate student, I thought I was a man who was only interested in harmonic analysis and the idealism of pure mathematics; now I am a transgender woman who works in geometric measure theory, data science, and math education research. In this talk, I will tell a story about these transitions along multiple axes within mathematics. I will also discuss how my research and teaching have played a role in developing a completely different practice as a mathematician, and how this fits into the broader mathematical community.

Past Colloquia