1-2-3 Seminar is a student-ran seminar at the University of Washington that takes place every winter and spring quarter. This seminar is a place where we talk about topics near and dear to ourselves, geared towards engaging audiences that are graduate students across different fields. The format of each talk will be three examples in increasing complexity (1-2-3), presented with an emphasis on quality and engagement.
For the year 2025-2026, the 1-2-3 Seminar is organized by Zawad Chowdhury (zawadx@uw.edu) and Mallory Dolorfino (mallod2@uw.edu). If you would like the opportunity to present, please contact us!
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For speakers: we encourage you to choose any topic of math for your talk! There are only two requirements for your 50-minute talk:
Your talk should be formatted around three examples of increasing complexity (1-2-3). Theorems are not considered examples!
Your talk should be accessible to graduate students in other fields. People with just a background from first-year courses should understand at least the first half of your talk.
Check out the previous years' schedule if you need ideas!
This year, we're adding an option for speakers to get feedback from the audience (through a form you opt into), as well as new challenges you can incorporate into your 1-2-3 talk (for speakers who would like a bit more of a... trial). Some possible challenges include:
5 levels: Give the same talk but at five levels of understanding (someone not into math, a high schooler, a math major, another math grad student and your advisor)
Pictionary: Only images in your slides
Socratic Method: The talk is delivered mostly by asking questions
Worksheet: Make a 12x-style worksheet for your talk
Taboo: Some terms are banned
Improv: Deliver a talk based on suggestions from the audience
Wedding Toast: Deliver a talk with stories, like a wedding toast
Time: Friday 3:30 - 4:30 pm (Different from before!!)
Location: Padelford C401 and on Zoom
Zoom Link: https://washington.zoom.us/j/92009646144
Note: the Zoom is open to all, but the recording requires an UW sign-in and expire 3 months after the date of the each talk. If you are outside of UW and would like to access to the recording please email us.
Speaker: Wolfgang Allred
Title: Equivariance for deranged
Abstract: Have you ever wondered what the hell a G-equivariant sheaf is? If so, then you're in good company. Drop by this Friday and we will explore equivariance together.
Speaker: Bryan Lu
Abstract: It has been said by many a combinatorialist that Y**ng d**gr*ms and Y**ng t*bl***x are intimately connected to the representation theory of the symmetric group. Indeed, (semi-)standard Y**ng t*bl***x index many interesting objects in the ring of characters of the symmetric group (read: ring of symmetric functions), but how do you use them to work with the actual representations themselves? We will explore at least three interesting ways that Y**ng d**gr*ms and Y**ng t*bl***x can be used to describe the irreducible representations of the symmetric group. Unfortunately, I have been cursed with the Taboo condition, so I will be incapable of saying some of the above words out loud...
Speaker: Micheal Zeng
Abstract: (This talk will be given as a Socratic Seminar.)
- How many roots does a polynomial have over the complex numbers? How about over the reals? Over any field?
- How many circles are simultaneously tangent to 3 circles in the plane, over C? How about over R? Over k?
- How many lines simultaneously meet 4 skew lines in 3-space?
- How many lines are there on a smooth cubic surface in 3-space? How many different types of lines are there?
- How many lines are there in a pencil of quartic surfaces in 3-space? What are the types of these lines?
- How many genus 1 curves are there on a (3,3)-Calabi-Yau threefold in 5-space?
- How do we know for sure???
Speaker: Ting Gong
Abstract: I will provide a worksheet about Brauer groups and we will work on it and talk about it. Depending on your level of knowledge you can pick what problems to solve but there are always problems to solve regardless of your knowledge.
Speaker: Haocheng Cai
Title: Measuring singularities in char 0 and p via "thresholds"
Abstract: Attach a real number to a mathematical object. If we are careful, we can get an "if and only if" statement of a property of the object in terms of whether a certain threshold value is reached. e.g. attach a number representing the effort spent and find a threshold value for completion of the PhD. The thresholds vary for different p (person/ characteristic). We will investigate two thresholds for singularities, log canonical threshold in characteristic 0 and F-pure threshold in prime characteristic p. We will use them to rate the badness of the singularities of a polynomial or an ideal, and compute some examples.
Time: Friday 2:30 - 3:30 pm (Different from before!!)
Location: Padelford C401 and on Zoom
Zoom Link: https://washington.zoom.us/j/92009646144
Note: the Zoom is open to all, but the recording requires an UW sign-in and expire 3 months after the date of the each talk. If you are outside of UW and would like to access to the recording please email us.
Speaker: Alex Wang
Title: 10 things I hate about grad school
Abstract: Inspired by the 1999 romantic comedy 10 Things I Hate About You, I step on my soapbox to discuss the complaints I have, advice I'd give, and lessons I've learned while navigating graduate school in Seattle. As my perspective is just one of many, I welcome and encourage others to share their experiences, but ask that attendance is limited to graduate students only.
Speaker: Charlie Magland
Title: Representations of braided Hopf algebras
Abstract: You don't love Hopf algebras enough! In this talk we will learn how Hopf algebras give a monoidal structure to their representations through simple examples in group theory, super vector spaces, and, if there's time, Yetter–Drinfeld modules. We will observe how switching our braiding can completely change our category of representations. Fear not! Every example we tackle can be understood using only linear algebra.
Zoom recording (UW Sign-in required)
Speaker: Justin Bloom
Title: Dialogue on complexity and rigidity.
Abstract: What is complexity, in mathematics? What is rigidity, in mathematics? I have a strong suspicion that these two notions may be related, but when I present my metamathematical theorem relating them, you should find this relationship to be dubious. By raising your doubts, we will approach a more refined definition for both of these mathematical notions, and for the contexts in which they are tied to one another, by means of critical dialogue.
Speaker: Bryan Lu
Title: Standard n-Simplex and Complex Projective Space
Abstract: You are cordially invited to PDL C-401 to celebrate the beautiful connection between the standard n-simplex and the complex projective space. A series of three guests will toast these interconnected partners and illustrate the deep chemistry that unites many pairs of members between the family of polytopes and the family of projective toric varieties. Please feel free to come even if one is not so familiar with algebraic geometry -- any speakers from the algebraic geometry community will be sure to introduce themselves thoroughly. Refreshments will be served in PDL C-120 following the speeches.
Speaker: Varun Shah
Title: Primes, Parity, and Partitions
Abstract: Why is 7¹³¹−7 divisible by 131? How can we easily tell whether \binom{146}{k} is odd? Why is the number of such k a power of 2? In this talk, we explore how many such questions can be answered using a single tool: bijective combinatorics. By realizing these familiar expressions as sizes of sets of combinatorial objects, divisibility and parity emerge from hidden symmetries of these sets.
Since this is a pictionary talk, all proofs will be proofs in pictures.
Speaker: Mallory Dolorfino
Title: Solvable Points on Varieties
Abstract: What is a solvable point, why do we care about them, and when should (or shouldn't) a variety have many of them? This talk will be a friendly introduction to solvable points on varieties, intended for a broad audience, in which we will answer each question above. In doing so, we will introduce the guiding principle of arithmetic geometry -- that interesting arithmetic occurs for a geometric reason -- and we will see an example of this in the case of studying solvable points on curves.
In addition, this is an improv talk, so the audience will decide its direction! I will come prepared to answer questions about three recent papers in the area, and the audience can ask about any of them (or anything else!).
Speaker: Lauren Nowak
Title: TBA
Abstract:
Speaker: Clare Minnerath
Title: TBA
Abstract: