Hahn Lheem

Equipe Théorie des nombres

Institut de Mathématiques de Jussieu-Paris Rive Gauche (UMR7586)

About

I am a first year Ph.D. student in Mathematics at the Institut de Mathématiques de Jussieu-Paris Rive Gauche (IMJ-PRG). I am advised by Loïc Merel and Olivier Fouquet.

In 2025, I completed the M2 master's program in mathématiques fondamentales at Sorbonne Université, funded by the Paris Graduate School for Mathematical Sciences (PGSM) fellowship. I was supervised by Christophe Cornut for my M2 mémoire.

In 2024, I completed my undergraduate degree in mathematics at Harvard, where I was supervised by Barry Mazur for my senior honors thesis.

I was involved in the PROMYS program for several years, both as a student and counselor. I grew up in North Carolina.

Research Interests

Special values of L-functions, Harris-Venkatesh Conjecture, modular forms (especially those of weight 1), Eisenstein ideal, Stark conjectures, eigenvarieties

Contact

Email:
first [dot] last [at] imj-prg [dot] fr
Office:
Sophie Germain 747
Address:
Université Paris-Cité Bâtiment Sophie Germain 8 Place Aurélie Nemours 75013 Paris, France

Activities

I am currently co-organizing a learning seminar on p-adic Hodge theory with a view towards p-adic L-functions with Zheng Wang. You can find the notes for my talks below.

Conferences that I have attended/plan to attend:

  • (May 18-22, 2026 in NYC) The Eisenstein Ideal and Galois Representations: Looking Forward after 50 Years. link
  • (Jan 26-30, 2026 at CIRM) Around the Langlands program, Week 1: Winter School on Galois representations and automorphic forms. link
  • (Oct 27-31, 2025 at IHES) New Structures and Techniques in p-adic Geometry. link

Writings

Expository

  1. Introduction to p-adic Hodge theory, d'après Fontaine. (Talk for Colmez Tsinghua learning seminar) pdf
  2. The Eichler-Shimura Isomorphism. (Final presentation for Jacques Tilouine's M2 course on L-functions of modular forms) pdf
  3. The Weil Conjectures for abelian varieties. (Final presentation for Anna Cadoret's M2 course on Galois representations and motives) [Joint with Tommaso Lucantoni] pdf
  4. Representation Theory. (PROMYS 2024 counselor seminar) pdf

Course Notes

  1. Elliptic Curves, taught by Javier Fresàn [M2 student, winter 2024] pdf
  2. Number Theory (Harvard Math 124), taught by Mark Kisin [course assistant, fall 2023] pdf
  3. Algebraic Geometry (Harvard Math 137), taught by Mihnea Popa [course assistant, spring 2023] pdf
  4. Group & Ring Theory (Harvard Math 122), taught by Niki Myrto Mavraki [course assistant, fall 2022] pdf

Talks

Past talks

  • (Dec 13, 2025) Introduction to p-adic Hodge theory, d'après Fontaine. Colmez Tsinghua learning seminar.
  • (May 6, 2024) Where the Wild Forms Are. Harvard Math Table.
  • (Jan 4, 2024) Gamma Factors for Representations of General Linear Groups over Finite Fields. Joint Mathematics Meeting. Note: could not attend myself, but Nir Elber presented our joint work.
  • (July 14, 2023) One GL2, Two GL2, Red GL2, Blue GL2. Summer Undergraduate Michigan Mathematics Research Conference.

Affiliations

  • I spent five summers at the PROMYS program (Student 2017-18, Junior Counselor 2019, Counselor 2022, Head Counselor 2024).
  • I helped organize the Harvard-MIT Mathematics Tournament (HMMT) for three years (Problem Staff 2019-21, Community Coordinator 2021-22).
  • I sang in the Harvard Glee Club for three years (2021-24).