I'm a PhD student at the University of Washington where I am advised by Anna Karlin and Shayan Oveis Gharan. I graduated from Oberlin College and Conservatory in 2016 and spent some time in industry before coming to UW in 2018.

I mainly study approximation algorithms. Recently I have been using ideas from combinatorics and the geometry of polynomials to help analyze algorithms for TSP and other optimization problems. Here is my CV.

I will be at the Institute for Advanced Study for the 2023 - 2024 academic year and then will be joining Boston University as an Assistant Professor in the summer of 2024. I will be looking for students starting in 2024. If you are interested, apply to BU this fall and feel free to reach out. We have a strong and growing theory group and are a part of Boston's vibrant academic community.

**Recent papers **(all):

- Thin Trees for Laminar Families

N. Klein and N. Olver

2023

- A (Slightly) Improved Deterministic Approximation Algorithm for Metric TSP

A. Karlin, N. Klein, S. Oveis Gharan*IPCO 2023*

- A 4/3-Approximation Algorithm for Half-Integral Cycle Cut Instances of the TSP

B. Jin, N. Klein, D. Williamson*IPCO 2023*

- Matroid Partition Property and the Secretary Problem

D. Abdolazimi, A. Karlin, N. Klein, S. Oveis Gharan*ITCS 2023*

- A (Slightly) Improved Bound on the Integrality Gap of the Subtour LP for TSP

A. Karlin, N. Klein, S. Oveis Gharan*FOCS 2022*

ICERM talk (structure of near min cuts)

- An Improved Approximation Algorithm for the Minimum k-Edge Connected Multi-Subgraph Problem

A. Karlin, N. Klein, S. Oveis Gharan, X. Zhang*STOC 2022*

- A (Slightly) Improved Approximation Algorithm for Metric TSP (journal version)

A. Karlin, N. Klein, S. Oveis Gharan*STOC 2021*(Best paper award)

APPROX 2020 invited talk (a high level overview)

IGAFIT colloquium (slightly less technical overview)

Geometry of Polynomials talk (focuses more on Strongly Rayleigh distributions)

- An Improved Approximation Algorithm for TSP in the Half Integral Case

A. Karlin, N. Klein, S. Oveis Gharan*STOC 2020*

TCS+ talk (long version), STOC talk (shorter version)

**Other writing: **a short article on approximating TSP (for the general public)

**Misc:**concerning waffles / concerning primes / concerning math games

## Contact

Email: nathan dot klein711 at gmail dot com