Relationships between skein algebras (Helen Wong, CMC)
2026-02-03 12:15 - 13:10 (America/Los_Angeles) | Estella 2099
We will examine the multiplicative structure of two skein algebras— the usual Kauffman bracket skein algebra of a surface (generated by loops) and a generalization of it due to Roger-Yang (generated by loops and arcs). In joint work with Chloe Marple, we found a homomorphism between the usual skein algebra for a closed torus and the Roger-Yang skein algebra for a twice-punctured annulus. In this talk, I’ll present some ways we used that homomorphism to do computations, and whether there might be similar relationships between skein algebras of other surfaces.

CCMS Colloquium: Teal Witter (CMC)
2026-02-06 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Teal Witter (CMC)

Title: Exactly Computing do-Shapley Values

Abstract:
Causal questions lie at the heart of scientific inquiry, from evaluating economic policies to determining medical treatments. Yet, observational data alone is often insufficient due to the fundamental problem of causal inference: we cannot observe the counterfactual world where a specific intervention did not occur. Structural Causal Models (SCMs) offer a powerful solution by explicitly modeling the underlying mechanisms of a system. By formalizing data generation, SCMs allow us to use the do-operator to rigorously simulate interventions, answering questions like, “If a patient were administered prednisone and made to stop smoking, what would be their expected pain level?”

However, characterizing a system through individual queries is computationally daunting. As the number of features d grows, the landscape of possible interventions scales exponentially (2^d). To extract interpretable insights from this combinatorial complexity, we utilize the do-Shapley value, a game-theoretic framework that attributes the complicated dynamics of an SCM to individual features.

In this talk, I will present a new algorithmic approach that makes computing these values more tractable. We show that the causal landscape is structured into “irreducible sets”, a building block where multiple interventions yield identical effects. By leveraging this structure, we introduce an algorithm that computes do-Shapley values exactly, with runtime that depends on the graph’s complexity rather than 2^d. We further propose an estimator that targets these sets directly, producing more accurate estimates than prior work by several orders of magnitude or more.

Joint work with Álvaro Parafita, Tomas Garriga, Maximilian Muschalik, Fabian Fumagalli, Axel Brando, and Lucas Rosenblatt.

Bio: Teal is an Assistant Professor of Mathematics and Computer Science at Claremont McKenna College. His recent research explores randomized algorithms for problems in explainable AI and generative AI. More broadly, he is interested in leveraging ideas from theoretical computer science and machine learning to design provably accurate algorithms. Before joining the consortium, Teal completed his Ph.D. in Computer Science at New York University, where he was supported by an NSF Graduate Research Fellowship. Prior to graduate school, Teal attended Middlebury College.

GEMS February 7th Session
2026-02-07 10:00 - 11:55 | Shanahan B450, Harvey Mudd College, 301 Platt Blvd., Claremont, 91711, United States
This GEMS session will be facilitated by Professor Teal Witter from Claremont McKenna College.

Title: Who Can Write Down the Bigger Number?

Abstract:
If you had fifteen seconds to write the largest distinct whole number possible on an index card, what would you write? While most would look to the physical world for inspiration—counting the grains of sand in the Sahara or the atoms in the observable universe—we will explore much larger numbers. Our journey will take us beyond the limits of scientific notation, moving from “power towers” and the mind-bending Ackermann function to the very edge of computer science. Ultimately, we will arrive at the “Busy Beaver” sequence: numbers so unfathomably vast that they are theoretically uncomputable. Join us to explore the boundaries of language, logic, and the truly gargantuan.

A BKM-type criterion for the 3D incompressible Euler equations (Mustafa Aydin, USC)
2026-02-09 16:15 - 17:15 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: The three-dimensional incompressible Euler equations describe the motion of an ideal fluid, yet the mechanisms that govern the possible loss of regularity of smooth solutions remain only partially understood. A classical result of Beale, Kato, and Majda shows that if a smooth solution breaks down in finite time, then the time integral of the vorticity’s supremum norm must diverge, providing a sharp conditional criterion for regularity.
In this talk, I will present a new blow-up criterion in the spirit of the Beale–Kato–Majda theorem that emphasizes a different form of control. Instead of requiring bounds on the full vorticity, the criterion involves tangential derivatives of the velocity field, and shows that smooth solutions persist as long as these derivatives remain appropriately bounded in time. The result holds in a variety of settings, including the whole space, periodic domains, and domains with boundaries.

Analysis Seminar: Generalized Elmendorf’s Theorem in Context (Sofía Martínez Alberga, Bryn Mawr College)
2026-02-12 16:15 - 17:15 | Estella 2099, Pomona College, 610 N. College Ave., Claremont, CA, United States
Abstract: In general, the objective of algebraic topology is to classify spaces using some algebraic invariants or up to some notion of equivalence. In the area of equivariant homotopy theory, the goal is the same but now spaces equipped with a group action are considered and algebraic invariants of choice are homotopy groups. It turns out there is an analogous version of Whitehead’s theorem in the equivariant setting which in some sense motivates studying weak homotopy equivalences over homotopy equivalences. This talk will review some of these homotopical notions and introduce Elmendorf’s theorem. Proved in the eighties, this theorem sheds some light on how one can better understand equivariant homotopical notions as functors from the orbit category of the group to the category of topological spaces. Also, in this talk we will address how this perspective is used more modernly to understand better equivariant notions of other categories and to expand nonequivariant notions to equivariant ones.

CCMS Colloquium: Sofia Martinez Alberga (Bryn Mawr College)
2026-02-13 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Sofia Martinez Alberga (Bryn Mawr College)

Title: Stay in the Loop and Fun Group

Abstract: In this talk, we will discuss the goal of algebraic topology. After we will discuss a topological space that can be associated with any topological space, say $X$, and base point, $b in X$: the based loop space denoted $Omega(X, b)$. The loop space has some interesting algebraic structure that allows us to define an invariant for spaces. We will see how this invariant can be used more generally and when the action of a group is present on the space.

Bio: Dr. Sofía Martínez Alberga is a Research Associate at Bryn Mawr College working in algebraic topology. Originally born and raised in southern California, she earned her Bachelor’s of Science in mathematics from the University of California, Riverside in 2019 and that same year she won the NSF Graduate Research Fellowship and the Math Alliance Fellowship. Dr. Martínez Alberga earned her PhD from Purdue University and during graduate school, she held roles like MSRI-Undergraduate Program graduate research assistant, Enhancing Diversity Graduate Education summer program graduate mentor, and Women In Science Programs (WISP) Liaison. Furthermore Dr. Martínez Alberga has been invited to attend and speak at conferences and seminars internationally and has organized and secured grants for sessions at major conferences such as JMM.

Explainability and Analysis of Variance (Zijun Gao, USC)
2026-02-16 16:00 - 17:00 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: Existing tools for explaining complex models and systems are associational rather than causal and do not provide mechanistic understanding. We propose a new notion called counterfactual explainability for causal attribution that is motivated by the concept of genetic heritability in twin studies. Counterfactual explainability extends methods for global sensitivity analysis (including the functional analysis of variance and Sobol’s indices), which assumes independent explanatory variables, to dependent explanations by using a directed acyclic graphs to describe their causal relationship. Therefore, this explanability measure directly incorporates causal mechanisms by construction. Under a comonotonicity assumption, we discuss methods for estimating counterfactual explainability and apply them to a real dataset dataset to explain income inequality by gender, race, and educational attainment.
Bio: Zijun Gao is a tenure-track assistant professor in the Department of Data Sciences and Operations at USC Marshall Business School. She received her Ph.D. in Statistics from Stanford University in 2022 supervised by Professor Trevor Hastie. She served as a research associate in the Statistical Lab at the University of Cambridge from 2022 to 2023 hosted by Professor Qingyuan Zhao. Her research focuses on the estimation and inference problems in causal inference with heterogeneity, with side interests in distribution learning, selective inference, and model evaluation. She also works on real-world data motivated topics, with a specific emphasis on the applications in adaptive clinical trial and personalized medication.

Summer of Math Discovery: Two research projects on combinatorial polytopes (Andrés R. Vindas Meléndez, HMC)
2026-02-17 12:15 - 13:10 | Estella 2099
This is a talk in two parts covering two projects that the speaker mentored over the summer of 2025. The first project deals with the study of polytopes that arise from the convex hulls of stack-sorting on particular permutations. The second project deals with the study of symmetric edge polytopes of a finite simple graph, a centrally symmetric lattice polytope whose vertices are defined by the edges of the graph. Both projects studied the (Euclidean, relative, or normalized) volumes of the respective combinatorially defined polytope.

Analysis Seminar: Choquet simplices of groups and C*-algebras (Itamar Vigdorovich, UCSD)
2026-02-19 16:15 - 17:15 | Estella 2099, Pomona College, 610 N. College Ave., Claremont, CA, United States
Abstract: Let C be a compact convex set (in a locally convex topological vector space). By Choquet’s theorem, every point in C is the barycenter of a probability measure supported on the extreme points. When this representing measure is unique, C is called a simplex.
Simplices arise naturally in various fields of mathematics: the space of invariant probability measures of a dynamical system is a simplex, and so is the space of tracial states on a C*-algebra. In the group case, the simplex of characters provides a framework for a non-commutative Fourier transform.
I will also discuss results and phenomena for traces of free products, fundamental groups of surfaces, Kazhdan groups, and related classes.

CCMS Colloquium: Mary Lou Zeeman (Bowdoin College)
2026-02-20 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Mary Lou Zeeman (Bowdoin College)

Title: A new framework for studying transient reactivity in two-dimensional systems.

Abstract: Even if a linear system of ordinary differential equations (ODEs) has a globally attracting equilibrium, solutions of the ODEs may grow arbitrarily large in the short-term before returning to the equilibrium in the long-term. This counter-intuitive phenomenon of transient amplification is called reactivity. It is especially important in ecological resilience and other applications where disturbances of a system may be transiently magnified to undesirable levels. In this talk we introduce a new framework for analyzing reactivity in two-dimensional linear systems of ODEs. While the eigenstructure of the system captures the long-term dynamics, we use the new framework to define an orthostructure, dual to the eigenstructure, that captures transient reactivity dynamics of the system. By interweaving the eigen- and ortho-structures, we are able to exactly quantify the maximum disturbance amplification possible.

Bio: Mary Lou Zeeman is the Wells Johnson Professor of Mathematics at Bowdoin College. Her research is in dynamical systems with applications to biology, sustainability and resilience. She is known for collaboratively building cross-disciplinary research communities focused on the health of the planet. She helped found and co-lead the Mathematics and Climate Research Network, the Computational Sustainability Network and the SIAM Activity Group on Mathematics of Planet Earth.

CCMS Colloquium: Harrison Li (HMC)
2026-02-27 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Harrison Li (HMC)

Title: Precise analysis of blocked randomized experiments

Abstract: I recently finished a multi-year project with collaborators analyzing a blocked randomized experiment to evaluate the effectiveness of a government job training program for unemployment insurance (UI) recipients in Rhode Island. In presenting the results, I will focus on some methodological considerations that arose organically in this context. I will start by providing an introduction to the potential outcomes framework in causal inference and show how it enables us to formulate a precise mathematical description of what exactly it is we want to estimate when running a randomized experiment. Then, we will see some principled and less principled methods for performing this estimation in the setting of a block randomized experiment. Some directions for ongoing and future research will be discussed.

Bio: Harrison Li is in his first year as an Assistant Professor of Mathematics at Harvey Mudd College. He comes to Claremont after finishing his graduate studies in statistics at Stanford University in 2025, and previously worked full time as a quantitative trader on Wall Street. His research interests center around variance reduction in randomized experiments through experimental design and/or novel estimation procedures. He is also very passionate about developing sound statistical methodology in the service of other disciplines, including climate science, agronomy, and economics, and about exposing more students to the mathematical aspects of probability and statistics.

Structure-Preserving Discretizations for Fokker–Planck Equations via the Energy Dissipation Law (Satish Chandran, UCR)
2026-03-02 16:15 - 17:15 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: We present a new approach for deriving structure-preserving numerical discretizations of Fokker-Planck equations by establishing a connection between the Fokker-Planck equation and its semi-discrete master equation at the level of the energy-dissipation law. We determine the transition rate in the master equation via the detailed balance condition and the spatial discretization of the continuous energy-dissipation law. This approach ensures that the semi-discrete master equation satisfies the detailed balance condition and converges to the correct equilibrium. In addition to recovering existing transition rates proposed in earlier works, our framework uncovers new transition rates that have not been discussed in the current literature. This work is joint with Dr. Yiwei Wang (UCR).

On a new version of Siegel’s lemma (Lenny Fukshansky, CMC)
2026-03-03 12:15 - 13:10 | Estella 2099
The classical Siegel’s lemma (1929) asserts the existence of a nontrivial integer solution to an underdetermined integer homogeneous linear system, whose “size” is small as compared to the size of the coefficients of the system. Far-reaching generalizations of this theorem, producing a full basis for the solution space, were obtained over number fields by Bombieri & Vaaler (1983), and over the field of algebraic numbers by Roy & Thunder (1996), where the “size” was measured by a height function. We obtain a new version of Siegel’s lemma, bridging the Bombieri & Vaaler and Roy & Thunder results in two ways: (1) our basis lies over a fixed number field as in Bombieri & Vaaler’s theorem; (2) our height-bound does not depend on the number field in question as in Roy & Thunder’s theorem. Our result does not imply the previously established ones and is not implied by them, and our basis has some additional interesting properties. Our method is quite different from the previous ones, using only linear algebra. Joint work with Max Forst.

CCMS Colloquium: Lihong Zhao (Kennesaw State University)
2026-03-06 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Lihong Zhao (Kennesaw State University)

Title: Capturing heterogeneity in malaria transmission: an age-structured model with immune feedback and seasonality

Abstract: Malaria remains a major global health burden, causing more than 600,000 deaths and over 249 million cases globally each year. Heterogeneity in malaria transmission is a critical factor that influences the dynamics of disease emergence and the effectiveness of possible control strategies. In this talk, I will present an age-structured model that couples vector-host epidemiological dynamics with immune feedback and how we use it to characterize seasonal malaria transmission and assess the impact of vaccination strategies. We also extend this model to explore how different mobility patterns and immunity profiles interact to impact the risk of severe infection and prevalence.

Bio: Dr. Lihong Zhao is an Assistant Professor of Mathematics at Kennesaw State University (KSU). Prior to her position at KSU, she was a Visiting Assistant Professor in the Department of Mathematics at Virginia Tech and an NSF DIRAC-RTG postdoctoral fellow in the Department of Applied Mathematics at the University of California, Merced. She develops and analyzes mathematical and computational models to examine questions in life sciences. Most of her work focuses on infectious disease epidemiology and ecology.

GEMS March 7th Session
2026-03-07 10:00 - 11:55 | Shanahan 1480, Harvey Mudd College, 301 Platt Blvd., Claremont, CA, 91711, United States
This GEMS session will be facilitated by Robbie Tran from Claremont Graduate University.

Title: Formulating Equations as a Medium for Digital Art and Design

Abstract:
As we can utilize letters and words to write out mathematics (e.g. 2+2=4 can be written as “two plus two is equal to four”), this session seeks to explore the near reverse: how can we use mathematics to some extent graph letters and words? Rather, could we formulate equations of curves that visually resemble text on a 2D-plane? If we include both conventional and nonconventional shapes too, this question is not only an interesting curiosity, but a question whose answer is quite prevalent in programs for computer graphics, animation, digital art, and font design!

We will approach this question by highlighting and constructing Bézier curves, which can approximate smooth curves by control (anchor) points on the plane. Furthermore, this session will showcase the mathematics of these curves, covering polynomials, linear interpolation, and parametrization (no prior knowledge assumed). Ultimately, we will simulate how graphs of Bézier curves can be drawn for various letters and shapes by applying a recursive method called de Casteljau’s algorithm. Join us to explore an example of how mathematics can serve as a gateway to art and design!

An Odd Estimator for Shapley Values (Teal Witter, CMC)
2026-03-09 16:15 - 17:15 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: The Shapley value is a ubiquitous framework for attribution in machine learning, encompassing feature importance, data valuation, and causal inference. However, its exact computation is generally intractable, necessitating efficient approximation methods. While the most effective and popular estimators leverage the paired sampling heuristic to reduce estimation error, the theoretical mechanism driving this improvement has remained opaque. In this work, we provide an elegant and fundamental justification for paired sampling: we prove that the Shapley value depends exclusively on the odd component of the set function, and that paired sampling orthogonalizes the regression objective to filter out the irrelevant even component. Leveraging this insight, we propose OddSHAP, a novel consistent estimator that performs polynomial regression solely on the odd subspace. By utilizing the Fourier basis to isolate this subspace and employing a proxy model to identify high-impact interactions, OddSHAP overcomes the combinatorial explosion of higher-order approximations. Through an extensive benchmark evaluation, we find that OddSHAP achieves state-of-the-art estimation accuracy.

Joint work with Fabian Fumagalli, Landon Butler, Justin Singh Kang, and Kannan Ramchandran.

Hecke algebras and motives (Robert Cass, CMC)
2026-03-10 12:30 - 13:10 | Estella 2099
Hecke algebras play a central role in both number theory and representation theory. While some Hecke algebras have explicit descriptions in terms of generators and relations, others are understood through structure constants that encode multiplicities in tensor products of representations. In this talk, I will discuss several projects with Thibaud van den Hove and Jakob Scholbach aimed at using geometry and motives to give a uniform categorification of Hecke algebras. Along the way, we will encounter the geometric Satake equivalence, Gaitsgory’s central functor, and Iwahori-Whittaker models.

NO CCMS Colloquium: Pi Day at CMC
2026-03-13 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
No lecture today.

Quantitative and Computing Lab (QCL) Math Club Pi Day celebration at Claremont McKenna College at Kravis Lower Court from 11am to 12:30pm.

NO CCMS Colloquium - SPRING BREAK
2026-03-20 11:00 - 12:15

A Regularity Criterion for the 3-D Navier-Stokes Equations Based on Finitely Many Observations (Abhishek Balakrishna, USC)
2026-03-23 16:15 - 17:15 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: This talk presents a regularity criterion for the three-dimensional Navier–Stokes equations based on finitely many observations of the flow. Motivated by data assimilation, we study a nudging algorithm that incorporates coarse spatial measurements through general interpolation operators.
We show that suitable conditions on the observed data guarantee global regularity of the associated system and yield an exponential tracking property. As a consequence, we obtain a new regularity criterion for weak solutions formulated entirely in terms of finitely many observables, covering modal, volume, and nodal measurements.

Computing certificates for complete positivity (Achill Schürmann, University of Rostock)
2026-03-24 12:15 - 13:10 | Estella 2099
A key problem in computer proofs based on solutions from copositive optimization, is checking whether or not a given quadratic form is completely positive or not. In this talk we describe the first known algorithm for arbitrary rational input. It is based on a suitable adaption of Voronoi’s Algorithm and the underlying theory from positive definite to copositive quadratic forms. We observe several similarities with the classical theory, but also some differences, in particular for three and more variables. A key element and currently the main bottleneck in our algorithm is an adapted shortest vector computation, asking for all nonnegative integer vectors attaining the copositive minimum of a given copositive quadratic form.
(based on joint work with Valentin Dannenberg, Alexander Oertel, Mathieu Dutour Sikiric and Frank Vallentin)

Analysis Seminar: Metrics on quantum channels from noncommutative geometry (Tron Omland, University of Oslo and Norwegian National Security Authority)
2026-03-24 16:15 - 17:15 | Estella 2099, Pomona College, 610 N. College Ave., Claremont, CA, United States
Abstract: We study metrics on completely positive maps, and in particular on quantum channels, induced by seminorms from noncommutative geometry. Using an infinite-dimensional analogue of the Choi–Jamiołkowski correspondence, we construct such metrics and show that, under suitable assumptions, they satisfy stability and chaining. I will present the main ideas and explain how spectral triples and related constructions give rise to distances between quantum processes. This is joint work with Austad, Bedos, Eidesen, and Larsen.

NO CCMS Colloquium - Cesar Chavez Day
2026-03-27 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States

The Euler Equations in Function Spaces of Generalized Smoothness (Zachary Radke, OSU)
2026-03-30 16:15 - 17:15 | Emmy Noether Room, Estella 1021, Pomona College,, 610 N. College Ave., Claremont, CA, 91711, United States
Abstract: In this talk, we will describe a well/ill-posedness result for the 2D incompressible Euler equations. We investigate solutions in a setting logarithmically smoother than previously done, in a hope to identify the key dynamics leading to a breakdown of regularity in 2D fluid flow. When order of the logarithmic derivative is sufficiently large one obtains global well posedness, however, below this threshold, one can construct initial data for which the corresponding solution blows up instantaneously in the logarithmic Sobolev norm. In this sense, the result is sharp at this logarithmic scale, but by no means is the story completed by it so we will discuss ways to dive deeper.

Central moments of autocorrelation demerit factors of binary sequences (Daniel Katz, CSUN)
2026-03-31 12:15 - 13:10 | Estella 2099
A low autocorrelation binary sequence of length $ell$ is an $ell$-tuple of $+1$s and $-1$s that does not strongly resemble any translate of itself. Such sequences are used in communications and remote sensing for synchronization and ranging, where translation represents time delay. A single number that indicates how good a sequence is for such purposes, called the merit factor, was introduced by Golay. Its reciprocal is the demerit factor, which is more natural to analyze due to its connection with norms of polynomials on the complex unit circle. We consider the uniform probability measure on the $2^ell$ binary sequences of length $ell$ and investigate the distribution of the demerit factors of these sequences. Sarwate and Jedwab have respectively calculated the mean and variance of this distribution. For each positive integer $p$, we derive a formula for the $p$th central moment of the demerit factor for the binary sequences of length $ell$; this is $ell^{-2 p}$ times a quasipolynomial function of $ell$. The derivations rely on new combinatorial techniques, assisted by group theory and Ehrhart theory, and show that all the central moments are strictly positive for $pgeq 2$ and $ell geq 4$. Jedwab’s formula for variance is confirmed, and we go beyond previous results by also deriving an exact formula for the skewness (by hand) and for the kurtosis and the fifth moment (by computer). We obtain asymptotic values for all central moments in the limit as the length $ell$ of the sequences tends to infinity.

Analysis Seminar: Restricted isometries and operator norms on finite-dimensional $L^p$-spaces (Alonso Delfín Ares de Parga, CU Boulder)
2026-04-02 16:15 - 17:15 | Estella 2099, Pomona College, 610 N. College Ave., Claremont, CA, United States
Abstract: An isometry between two normed vector spaces is a linear map that preserves the norm (i.e., the length of each output agrees with the length of its input). For the classical $p$-norms, isometries have a very concrete description when $p
eq 2$: they are given by signed permutations of the coordinates.
In this talk, I will present a generalization of this result to restricted isometries, which are linear maps that preserve the norm only on a fixed subset of coordinates. I will discuss how this generalization could be used in the computation of certain $p$-operator norms, a problem that is known to be NP-hard in general.
This talk includes joint work carried out as part of two REU projects in 2024 and 2025.

CCMS Colloquium: Puttipong Pongtanapaisan (Pitzer)
2026-04-03 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
CCMS Colloquium invites you to a talk by Puttipong Pongtanapaisan (Pitzer)

Title: Derivatives and the Shape of Graphs

Abstract: Reading the title of this talk, perhaps you think you are going to hear about Calculus I. I stole the title from a section of Stewart’s popular calculus book. But actually, I am going to talk about geometry and topology, and the root idea already appears in Calculus I. In real life, shapes such as proteins and DNA can be tangled up in space. These can be modeled as graphs embedded in three-dimensional space, and some applied mathematicians also call these networks. In calculus, you learn that information about derivatives, such as the number of local maxima and where they appear, tells us a great deal about the graph itself. I am going to apply this same philosophy to knotted graphs in three-dimensional space and demonstrate that one protein is more complexly entangled than another.

Bio: Puttipong Pongtanapaisan obtained his Ph.D. at the University of Iowa, where he studied low-dimensional topology under the supervision of Dr. Maggy Tomova. His previous positions include a PIMS Postdoctoral Fellow at the University of Saskatchewan and a Postdoctoral Associate at Arizona State University. His research explores knotted shapes in confinement by analyzing the arrangement of local maxima and minima.

GEMS April 4th Session
2026-04-04 10:00 - 11:55 | Shanahan 1480, Harvey Mudd College, 301 Platt Blvd., Claremont, CA, 91711, United States
This GEMS session will be facilitated by Evan Rosenman from Claremont McKenna College

Title: Fair Votes? The Mathematics of Elections and Redistricting

Abstract: How do we know if an election is fair? In this interactive session, we’ll explore how math helps us answer that question. Students will experiment with drawing voting districts to see how drawing different district boundaries can change outcomes. They will also learn about alternative voting systems, such as ranked choice voting and approval voting, and how these might yield more representative outcomes than traditional “first-past-the-post” elections. Along the way, we’ll encounter ideas like Condorcet winners, and see how Statistics can help us learn about voting patterns from limited data. Join us to discover how geometry, algorithms, and probability shape modern elections.

ANTC talk -- Dagan Karp (HMC)
2026-04-07 12:15 - 13:10 | Estella 2099

CCMS Colloquium: Course Preview
2026-04-10 11:00 - 12:15 | Davidson Lecture Hall, CMC, 340 E 9th St, Claremont, CA, 91711, United States
