Joseph Muller's webpage

About me

I am a JSPS postdoctoral fellow at the Graduate School of Mathematical Sciences, the University of Tokyo with host professor Naoki Imai. I am interested in number theory and arithmetic geometry. More specifically, my research revolves around Shimura varieties and their cohomology.
Here is my Curriculum Vitae.

Email: [last name]@ms.u-tokyo.ac.jp

Publications

Published papers

• Cohomology of the Bruhat-Tits strata in the unramified unitary Rapoport-Zink space of signature (1;n-1) | link
  2023, Nagoya Mathematical Journal, 250, pp. 470-497. doi:10.1017/nmj.2022.39.

Preprints

• Nearby cycles on the local model for the GU(n-1,1) PEL Shimura variety over a ramified prime | pdf
  2025, arXiv:2502.17851, submitted.
• Cohomology of the Bruhat-Tits strata in the supersingular locus of the GU(1,n-1) Shimura variety at a ramified prime | pdf
  2024, arXiv:2407.14012, submitted.
• On the cohomology of the basic unramified PEL unitary Rapoport-Zink space of signature (1;n-1) | pdf
  2022, arXiv:2201.10229, submitted.

Talks

• The nearby cycles of the PEL GU(n-1,1) Shimura variety over a ramified prime.
  March 2025, Waseda University Number Theory Symposium 2025 — Tokyo. | Link, Slides
• The nearby cycles of the PEL GU(n-1,1) Shimura variety over a ramified prime.
  February 2025, Aichi Number Theory Seminar (ANTS) — Nagoya. | Link, Slides
• Cohomology of supersingular loci of Shimura varieties of Coxeter type.
  October 2024, One day workshop on Shimura varieties and related moduli stacks — Kyoto. | Link
• Cohomology of the supersingular locus of certain PEL Shimura varieties of Coxeter type.
  December 2023, NTU x UTokyo joint conference 2023, Number Theory Session — Taipei. | Link, Slides
• On the cohomology of the unramified PEL unitary Rapoport-Zink space of signature (1,n-1).
  December 2022, RIMS Conference, Algebraic Number Theory and Related Topics 2022 — Kyoto. | Link, Slides
• On the cohomology of the unramified PEL unitary Rapoport-Zink space of signature (1,n-1).
  November 2022, MS Seminar — Kavli IPMU, the University of Tokyo. | Link
• On the cohomology of the unramified PEL unitary Rapoport-Zink space of signature (1,n-1).
  October 2022, Number theory seminar — Department of Mathematics, Kyoto University. | Link
• On the cohomology of the unramified PEL unitary Rapoport-Zink space of signature (1,n-1).
  July 2022, 21st Sendai-Hiroshima Number Theory Workshop — Tohoku University. | Link, Slides
• Cohomology of the unramified PEL unitary Rapoport-Zink space of signature (1,n-1).
  May 2022, Number theory seminar — Graduate School of Mathematical Sciences, the University of Tokyo. | Link
• Cohomologie des espaces de Rapoport-Zink PEL unitaires non ramifiés de signature (1,n-1), en niveau maximal.
  October 2021, Séminaire de Géométrie Arithmétique et Motivique — Institut Galilée, Université Sorbonne Paris Nord. | Link

Teaching

• 2022 Teaching assistant in Analyse 1, Algèbre 1, Algèbre 6, Intégration et Probabilités in Université Sorbonne Paris Nord.
• 2021 Teaching assistant in Analyse 1, Algèbre 1, Outils Mathématiques 1 in Université Sorbonne Paris Nord.
• 2020 Teaching assistant in Analyse 3, Algèbre 3, Mathématiques for the Economics and Business Science department in Université Sorbonne Paris Nord.

Miscellaneous

• Passed the JLPT N2 examination and the J-Test level pre-B examination in Japanese language proficiency in 2024.
• Solved the 16 problems of Orsay's mathematics marathon in the 2020/21 and 2021/22 editions.
  Link to the marathon's website.
• Passed the French agrégation competitive exam in mathematics in 2019, rank 8.
• Informal talk on Ramsey theory for undergraduate students as part of an event to promote the diffusion of mathematics.
  March 2018, Lycée du Parc, Lyon. | Slides