Solution to Lawvere's first problem: A Grothendieck topos that has proper class many quotient topoi
Gives a solution to Lawvere's first open problem.
- Academic ryuya_hora@zen.ac.jp
- Casual horaryuya38@gmail.com
- 2–4 November 2026OrganizingCategories in Tokyo 3.
- 14 November 2026TalkTitle pending — ZEN大学 ずしフェス -ZUSHI ACADEMIC FESTIVAL-, Zushi, Japan
- 8 December 2026TalkTitle pending — Intensive lecture for beginners, hosted by Masafumi Oizumi (The University of Tokyo)
- 27 December 2026TalkTitle pending — MATH EXPO 2026, Yokohama, Japan
- February 2027TalkTitle pending — AI for Math at Osaka
Also attending
- 7 November 2026Graduation research presentations at 東京都立科学技術高等学校, as a commentator for mathematics and information science.
- 16 November 2026AIと数学・理論物理のいま：GPT研究会から3年 at The University of Tokyo, Hongo Campus. tentative
- 23–24 November 2026AutumnFesta 2026.
- 1 December 2026NEDO 数学イノベーション共創イベント (second meeting) in Tokyo.
- 21–23 January 2027CGTC VI: Combinatorial Game Theory Colloquium VI. tentative
Current
- Assistant professor at ZEN University since April 2026
- Researcher at the HUMAI Center since April 2026
- Teaching modern mathematics at Math Space Topos since July 2020
- Advisor to 角川ドワンゴ学園 研究部 since June 2025
Organizing
- Categories in Tokyo — Founder and representative since April 2024
- AI for Math勉強会 — Founder and organizer since June 2026
Background
- Ph.D. in Mathematical Sciences, The University of Tokyo (2026) — Connectedness and full subcategories of topoi
- Master of Mathematical Sciences, The University of Tokyo (2024) — Two classification theorems of quotient toposes
- Bachelor of Science, The University of Tokyo (2022)
- Dean's award and Graduation Representative, Graduate School of Mathematical Sciences, The University of Tokyo, doctoral course. March 2026
- SLACS 2025 presentation award. October 2025