**Institutional email:** lenaji@umich.com

**Permanent email:** lenaji.math@gmail.com

**Office:** 1855 East Hall

Hello! I am an NSF Postdoctoral Fellow at the University of Michigan, mentored by Professor Mircea Mustaţă.

I am interested in algebraic geometry and its connections to arithmetic geometry and commutative algebra;

in particular, I am interested in rationality of algebraic varieties and in positive characteristic algebraic geometry.

I received my PhD from Princeton University in 2021 under the supervision of Professor János Kollár.

Before that, I was an undergraduate at Columbia University, where I graduated in 2016.

Outside of math, I like baking sourdough bread, trying various pastries, and occasionally drawing.

**Research (arXiv page):**

- Rationality of real conic bundles with quartic discriminant curve, with Mattie Ji. Preprint available at arXiv:2208.08916 (2022).
- Fano hypersurfaces with no finite order birational automorphisms, with Nathan Chen and David Stapleton. Preprint available at arXiv:2208.07396 (2022).
- Curve classes on conic bundle threefolds and applications to rationality, with Sarah Frei, Soumya Sankar, Bianca Viray, and Isabel Vogt. Preprint available at arXiv:2207.07093 (2022).
- The Noether–Lefschetz theorem in arbitrary characteristic. Preprint available at arXiv:2107.12962 (2021).
- Structure of geometrically non-reduced varieties, with Joe Waldron.
*Transactions of the American Mathematical Society*, Volume 374, Number 12 (2021), 8333–8363. - Completely controlling the dimensions of formal fiber rings at prime ideals of small height, with Sarah Fleming, S. Loepp, Peter McDonald, Nina Pande, and David Schwein.
*Journal of Commutative Algebra*, Volume 11, Number 3 (2019), 363–388. - Controlling the dimensions of formal fibers of a unique factorization domain at the height one prime ideals, with Sarah Fleming, S. Loepp, Peter McDonald, Nina Pande, and David Schwein.
*Journal of Commutative Algebra*, Volume 10, Number 4 (2018), 475–498.

**Upcoming travel:**

- University of Utah & AMS Fall Western Sectional Meeting, October 16–23, 2022
- Michigan State University, November 14, 2022
- University of Illinois Urbana-Champaign, November 29, 2022
- University of Notre Dame, December 6, 2022
- Birational Complexity of Algebraic Varieties, Simons Center, December 11–16, 2022

**Talk recordings:**

- The Noether–Lefschetz theorem in arbitrary characteristic (JAMI 2022, May 2022)
- Rationality of conic bundle threefolds over non-closed fields (Simons Foundation, February 2022)
- The Noether–Lefschetz theorem in arbitrary characteristic (AGNES Online, October 2021)

**Talk slides:**

- Rationality of conic bundle threefolds over non-closed fields (September 2022)
- The Noether–Lefschetz theorem in arbitrary characteristic (November 2021)
- Geometrically non-reduced varieties (November 2020)

**Teaching:**

- Fall 2021: Two sections of Math 115 (Calculus I)

**REU advice:**
Here is my advice for undergraduates on how to apply to REUs.

Here is a drawing of me by Emily Ji

Here is a younger me at the National Museum of Mathematics

*Last updated: October 2022.*