Ph.D. student in Computer Science at Northeastern University, advised by Prof. Rajmohan Rajaraman. I work at the intersection of theoretical computer science and machine learning. Recently, I've been studying the expressive power of attention, proving bounds on how many heads and reasoning tokens a transformer needs to compute a given function. More broadly, I'm interested in efficient and fair algorithms and interpretable models for healthcare, education, and resource allocation. Previously, I studied Math and Computer Science at Amherst College. During my free time, I enjoy taking pictures.

Threshold degree and the head complexity of single-layer attention

Under review

One Attention Head as a Minimal Universal Basis: The Token Complexity of Boolean Functions

Under review
2026

The Head Complexity of Boolean Functions in Single-Layer Attention

Rajaraman, R., Sundaram, R., & Tesfaye, A.

arXiv
2026

Two (narrow) heads are better than (an arbitrarily wide) one

Tesfaye, A., Kujawa, Z., Rajaraman, R., & Sundaram, R.

ICLR
Ph.D. Computer Science
Sept 2024 — Present
Northeastern University · Khoury College
B.A. Computer Science & Mathematics
Sept 2020 — May 2024
Amherst College
Study Abroad
Spring 2023
Aquincum Institute of Technology · Budapest, Hungary

Khoury Distinguished Fellowship · Amherst Memorial Fellowship

Always happy to chat about research collaborations. You can reach me at
tesfaye.am at northeastern dot edu.