Theory of Computation (TOC) Seminars

k-Coloring is Faster than Computing the Chromatic Number
Tuesday, September 15, 2026 - 4:15pm to 5:15pm
We prove that k-coloring on n-vertex graphs has a randomized algorithm running in time (2-eps_k)^n, where eps_k>0 for every fixed k. 
List Decoding Expander-Based Codes (up to capacity, in near-linear time)
Tuesday, May 12, 2026 - 4:15pm to 5:15pm
We will talk about a new framework based on graph regularity lemmas, for list decoding and list recovery of codes based on spectral expanders.
Adaptivity Does Not Help: Nearly Tight Lower Bounds for Boolean Monotonicity Testing
Tuesday, April 28, 2026 - 4:15pm to 5:15pm
Monotonicity testing asks: given a Boolean function f: {0,1}^n -> {0,1}, how many queries are needed to distinguish whether f is monotone or far from monotone? For nonadaptive algorithms, the query complexity was pinned down at \sqrt{n}.
Calibration in the Age of AI: From Prediction to Decision Making to AI Assisted Research
Tuesday, May 5, 2026 - 4:15pm to 5:15pm

Calibration serves as a trustworthy interface between prediction and decision making, and has (in my opinion) been getting only more important and interesting as a research topic as AI agents become commonplace.

Lower bounds for Learning Hamiltonians from Time Evolution
Tuesday, April 21, 2026 - 4:15pm to 5:15pm
How can we learn about quantum evolutions, given the ability to observe how it interacts with the real world?
Toy Models of Combinatorial Interpretability
Tuesday, April 14, 2026 - 4:15pm to 5:15pm

We introduce combinatorial interpretability, a methodology that offers a sandbox for understanding neural computation by analyzing the combinatorial structures in the sign-based categorization of a network's weights and bia

On zeros and algorithms for disordered systems
Tuesday, April 7, 2026 - 4:15pm to 5:15pm
Counting and sampling are fundamental algorithmic primitives in high-dimensional statistics and computer science.
Corners and Communication Complexity
Tuesday, March 17, 2026 - 4:15pm to 5:15pm

The corners problem is a classical problem in additive combinatorics. A corner is a triple of points (x,y), (x+d,y), (x,y+d). It can be viewed as a 2-dimensional analog of a (one-dimensional) 3-term arithmetic progression.

Graph-Based Algorithms for Similarity Search: Challenges and Opportunities
Friday, March 6, 2026 - 11:00am to 12:00pm
Interdiction problems and 2-person sequential games: beyond NP-completeness
Thursday, March 12, 2026 - 4:15pm to 5:15pm

In the Knapsack Problem (KP), a decision maker wants to select items of value V or more to put into a knapsack subject to a weight limit.  In the Interdiction Knapsack Problem (IKP), an adversary can block K items from being selected.  The adversary’s goal is to pr

Can we speed safely?
Tuesday, December 9, 2025 - 4:15pm to 5:15pm

Often, algorithmic tasks can be greatly sped up for inputs that are promised to have certain structural properties, such as inputs that are assumed to be random, or to come from restricted classes of graphs.

Redundancy is all you need (for CSP sparsification)
Tuesday, October 28, 2025 - 4:15pm to 5:15pm

Constraint Satisfaction Problems (CSPs) form a broad and central class in the theory of computation. I will describe a recent result (with J.

Introducing Algorithmic Thinking Theory for Foundation Models
Tuesday, October 14, 2025 - 4:15pm to 5:15pm
The last few months have witnessed tremendous advances on Large Language Model (LLM) reasoning capabilities with Gemini and GPT winning a gold medal at the International Mathematical Olympiad (IMO) [1] and International Collegiate Programming Contest (ICPC) [2].
On Beck-Fiala and Komlós Conjectures
Tuesday, October 7, 2025 - 4:15pm to 5:15pm

A conjecture of Komlós states that the discrepancy of any collection of unit vectors is O(1), i.e., for any matrix A with unit columns, there is a vector x with -1,1 entries such that |Ax|_\infty = O(1).

Sparsification of 1-in-3-SAT
Tuesday, September 16, 2025 - 4:15pm to 5:15pm

I will introduce a new notion of sparsification that doesn't drop constraints but merges variables. Using tools from additive combinatorics, I will then show that 1-in-3-SAT admits a sub-quadratic sparsifier.

A New Paradigm for Learning with Distribution Shift
Tuesday, September 9, 2025 - 4:15pm to 5:15pm

We revisit the fundamental problem of learning with distribution shift, where a learner is given labeled samples from training distribution D, unlabeled samples from test distribution D′ and is asked to output a classifier with low test error.

Explicit Lossless Vertex Expanders
Tuesday, September 23, 2025 - 4:15pm to 5:15pm

We give the first explicit construction of lossless vertex expanders. These are d-regular graphs where every small set S of vertices has (1-eps)d|S| distinct neighbors.

Deciding high-dimensional sub-Gaussian-ness in polynomial time
Tuesday, May 6, 2025 - 4:15pm to 5:15pm
Given samples from a probability distribution, can efficient algorithms tell whether the distribution has heavy or light tails?
Learning Multi-Index Models
Tuesday, April 15, 2025 - 4:15pm to 5:15pm

Multi-index models (MIMs) are functions that depend on the projection of the input onto a low-dimensional subspace.

How to Securely Implement Cryptography in Deep Neural Networks
Tuesday, April 22, 2025 - 4:15pm to 5:15pm

The wide adoption of deep neural networks (DNNs) raises the question of how can we equip them with a desired cryptographic functionality (e.g., to decr

Simulating Time With Square-Root Space
Tuesday, April 8, 2025 - 4:15pm to 5:15pm
Rapid Mixing at the Uniqueness Threshold
Tuesday, March 18, 2025 - 4:15pm to 5:15pm

Over the past decades, a fascinating computational phase transition has been identified in sampling from Gibbs distributions.

Overparametrized systems: from Smale's 17th problem to two-layer neural networks
Tuesday, March 11, 2025 - 4:15pm to 5:15pm

Training modern machine learning models requires to optimize highly non-convex risk function and yet simple gradient-based methods are able to find global minima for very high-dimensional problems.

Pseudorandom Correlation Generators
Tuesday, March 4, 2025 - 4:15pm to 5:15pm

Correlated secret randomness is an important resource for many cryptographic applications.

Good Locally Testable Codes
Tuesday, February 25, 2025 - 4:15pm to 5:15pm

An error-correcting code is locally testable (LTC) if there is a random tester that reads only a small number of bits of a given word and decides whether the word is in the code, or at least close to it.

On the Complexity of Neural Computation in Superposition
Tuesday, February 18, 2025 - 4:15pm to 5:15pm

Recent advances in neural networks interpretability suggest that superposition, the ability of a network to represent many more features than it has neurons, is a key mechanism underlying how neural networks compute.

"Local-to-Global" Theorems on High Dimensional Expanders
Tuesday, February 11, 2025 - 4:15pm to 5:15pm
Coboundary Expansion Inside Chevalley Coset Complex HDXs
Tuesday, December 10, 2024 - 4:15pm to 5:15pm
Recent major results in property testing and PCPs were unlocked by moving to high-dimensional expanders (HDXs) constructed from C_d-type buildings, rather than the long-known A_d-type ones.
A New Approach to Optimal Spectral Gaps
Tuesday, December 3, 2024 - 4:15pm to 5:15pm

It was conjectured by Alon in the 1980s that random d-regular graphs have the largest possible spectral gap (up to negligible error) among all d-regular graphs. This conjecture was proved by Friedman in 2004 in major tour de force.

Recent Advances in Differential Privacy under Continual Observation
Tuesday, November 26, 2024 - 4:15pm to 5:15pm

Differential privacy is one of the most popular definitions of privacy,

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