Cassandra Marcussen

I am a Ph.D. student in theoretical computer science at Harvard University, advised by Madhu Sudan. In 2022, I graduated from Columbia University, where I double-majored in Mathematics and Computer Science and was advised by Xi Chen. My research is supported by an NDSEG Fellowship.

I am interested in theoretical computer science and probability theory. I like to think about problems related to sublinear algorithms, random graphs, error correction, and stochastic processes.

My email is cmarcussen-at-g-dot-harvard-dot-edu.

Research

A Fast Coloring Oracle for Average Case Hypergraphs
with Edward Pyne, Ronitt Rubinfeld, Asaf Shapira, and Shlomo Tauber.
International Conference on Randomization and Computation (RANDOM) 2025.

Beyond Worst Case Local Computation Algorithms [pdf].
with Amartya Shankha Biswas, Ruidi Cao, Edward Pyne, Ronitt Rubinfeld, Asaf Shapira, and Shlomo Tauber.

Characterizing the Distinguishability of Product Distributions through Multicalibration [pdf].
with Aaron (Louie) Putterman and Salil Vadhan.
Computational Complexity Conference (CCC) 2025.

Finding the root in random nearest neighbor trees [pdf].
with Anna Brandenberger, Elchanan Mossel, and Madhu Sudan.

Errors are Robustly Tamed in Cumulative Knowledge Processes [pdf].
with Anna Brandenberger, Elchanan Mossel, and Madhu Sudan.
Conference on Learning Theory (COLT) 2024.
Proceedings of the National Academy of Sciences (PNAS) 2025.

Uniformity Testing over Hypergrids with Subcube Conditioning [pdf].
with Xi Chen.
Symposium on Discrete Algorithms (SODA) 2024.

Uniform scrambles on graphs [pdf].
with Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, and Shefali Ramakrishna.
Australasian Journal of Combinatorics, 2023.

Scramble number and tree-cut decompositions [pdf].
with Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, Shefali Ramakrishna, and Ben Weber.

Bounds on higher graph gonality [pdf].
with Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, and Shefali Ramakrishna.
Presented at the Young Mathematicians Conference, 2021.

Data Preparation of the nuMoM2b Dataset [pdf].
A. Goretsky, A. Dmitrienko, I. Tang, N. Lari, O. Kunhardt, R. Rashid Khan, C. Marcussen, A. Catto, D. Mallia, A. Leshchenko, A. Lin, A. Raja, A. Salleb-Aouissi, Itsik Pe'er, R. Wapner, C. Gyamfi-Bannerman. (Non-alphabetical author ordering)
Technical report.

Authors are ordered alphabetically unless otherwise indicated.

Teaching

At Harvard:

• Teaching Fellow for Essential Coding Theory (CS 229r) taught by Madhu Sudan (Fall 2023)

At Columbia, I was a Teaching Assistant for the following courses:

• Advanced Algorithms (COMS 4232) taught by Alexandr Andoni (Spring 2022)
• Introduction to Cryptography (COMS 4261) taught by Tal Malkin (Spring 2022)
• Analysis of Algorithms I (CSOR 4251) taught by Xi Chen (Summer 2021) and Alexandr Andoni (Fall 2021)
• Artificial Intelligence (COMS 4701) taught by Ansaf Salleb-Aouissi (Spring 2021)
• Discrete Mathematics: Combinatorics and Graph Theory (COMS 3203) taught by Ansaf Salleb-Aouissi (Fall 2020)

Other:

• TA for the PCMI Undergraduate Summer School on Quantum Computation (Summer 2023)
• I lectured and served as a TA for the Undergraduate Math Society's Introduction to Proofs workshop (Fall 2020, Fall 2021)

Fellowships and Selected Awards

• NDSEG Fellowship (2024)
• NSF GRFP Fellowship (2024, declined in favor of NDSEG)
• Magna cum laude, Columbia College (2022)
• John Jay Scholar – Columbia University Scholars Program (2018 - 2022)
• Verizon App Challenge: Best in Nation (2017)

Seminars and Organizations

• I currently organize TGINF, a theory seminar for graduate students and postdocs at Harvard.
• Columbia Undergraduate Learning Seminar in Theoretical Computer Science: Founder and Leader (Summer 2021 to Spring 2022). Organized reading groups on the analysis of Boolean functions and property testing (Summer 2021), A Theorist's Toolkit (Fall 2021), and High-Dimensional Probability and Applications to CS (Spring 2022).
• Columbia-Barnard Association for Women in Mathematics: Co-President (2021-2022). Organized reading groups on random walks (Summer 2020) and topology (Summer 2021).

Axioms

• Axiom 1. Mathematical potential is equally present in different groups, irrespective of geographic, demographic, and economic boundaries.
• Axiom 2. Everyone can have joyful, meaningful, and empowering mathematical experiences.
• Axiom 3. Mathematics is a powerful, malleable tool that can be shaped and used differently by various communities to serve their needs.
• Axiom 4. Every student deserves to be treated with dignity and respect.

Music