Activities - Conferences & Seminars

Conferences, workshops, and seminars organized by the members of the AHGT network.

The AHGT Seminar

An hybrid seminar that takes place between LPP Lille and RIMS Kyoto on a monthly basis by Zoom and which covers the three topics of the AHGT project. Contact the local organizer of your choice in case of interest.

RIMS Zoom Hybrid Org.: B. Collas (RIMS, JP), Y. Hoshi (RIMS, JP), K. Sawada (RIMS Kyoto), P. Dèbes (Lille, FR), A. Mézard (ENS, FR).

Seminars of the Network

RIMS Number Theory / Arithmetic Geometry Seminar (local)
Lille Arithmetic and Topology Seminars
Osaka Number theory Seminar
TIT Arithmetic and Geometry Seminar
Sorbonne-X ``Variétés Rationnelles'' Seminar
Sorbonne Paris Nord ``Géométrie Arithmétique et Motivique'' Seminar
ENS DMA ``Raconte-moi...'' Algebra and Geometry Seminar

Next coming talks…

May 12, 2025	Computations on Johnson cokernels by Sakasai Takuya*, The University of Tokyo, Japan.
Jun 16, 2025	When small points have their good reasons by Sara Checcoli, Institut Fourier Grenoble, France.
Jun 19, 2025	Integrally Hilbertian rings and the polynomial Schinzel hypothesis by Angelot Behajaina, Lille University, France.

Page of the AHGT seminar

AHGT Workshops and Conferences

Workshop Arithmetic France-Japan - 日本 x フランス数論幾何学 2025

Tokyo April 14-18, 2025 Org.: N. Imai (Tokyo), F. Lemma (IMJ-PRG) & T. Ochiai (IST).

Webpage of the workshop

[AHGT-LDTN&NT] Low-dimensional Topology and Number Theory XVI: Nakamura's 60th birthday

Workshop Low dimensional topology and number theory XVI: In honor of Professor Hiroaki Nakamura's 60th birthday (partner event)

Osaka March 25-28, 2025 Org.: M.Morishita (Kyushu), H.Ogawa (Osaka), T.Satoh (Tokyo), Akio Tamagawa (RIMS).

Webpage of the workshop Poster

Inter-universal Teichmüller Theory Summit 2025.

Kyoto Hybrid March 17-20, 2025 Org.: Y. Hoshi (RIMS), S. Mochizuki (RIMS), B. Collas (RIMS) & E. Lepage (IMG-PRG).

Webpage of the workshop

Algebraic & Arithmetic Geometry 2024. 6th Kyoto+ Workshop

Nanjing Zoom Hybrid October 25-29, 2024 Org.: Y. Yang (RIMS) et al.

Webpage of the workshop

[MFO24] Anabelian Geometry and Representations of Fundamental Groups

Anabelian Geometry and Representations of Fundamental Groups. Oberwolfach workshop

MFO-RIMS Sep. 29-Oct. 4, 2024 Org.: A. Cadoret, F. Pop, J. Stix, A.. Topaz

Webpage of the workshop

[MFO-RIMS23] Arithmetic Homotopy & Galois Theory

Arithmetic Homotopy & Galois Theory. Oberwolfach-RIMS tandem workshop

MFO-RIMS Sep. 24-29, 2023 Org.: B. Collas, P. Dèbes, Y. Hoshi, A. Mézard

Webpage of the workshop

[AHGT] Arithmetic & Geometry-Kyoto-Nanjing 2023

Algebraic & Arithmetic Geometry 2023. 5th Kyoto+ Workshop

Nanjing Zoom Hybrid Aug. 24-28, 2023 Org.: Y. Hoshi (RIMS), Z. Hu (Nanjing), P. Huang (Heidelberg), Y. Yang (RIMS), R. Zong (Nanjing)

Webpage of the workshop

Arithmetic & Homotopic Galois Theory 2023

ENS-RIMS Zoom Hybrid Mar. 20-24, 2023 Org.: B. Collas, P. Dèbes, Y. Hoshi, A. Mézard

Webpage of the workshop

AHGT Focus Workshops & Lecture Series

Focus events to introduce and report on the latest topics and progress of the arithmetic homotopy and Galois theory program.

[AHGT] Dawn · Midi · Yofuke International Seminar 2025

Dawn · Midi · Yofuke International Seminar 2025 - Explicit Methods in Homotopy and Arithmetic

Hybrid and Wesleyan, US Sep.-Oct, 2025 Org.: B. Collas, and C. Rasmussen

Webpage of the workshop

Anabelian Geometry in Yokohama 2025

Yokohama Sep. 02-03, 2025 Org.: B. Collas, Y. Ozeki, Y. Taguchi, and N. Yamaguchi

Webpage of the workshop

Spring seminar on Arithmetic Galois theory in Toyonaka 2025

Osaka - Toyonaka Mar. 31-Apr. 1, 2025 Org.: B. Collas, P. Dèbes, and H. Nakamura

Webpage of the workshop

[AHGT] Fresse Advanced course - Operads, graph complexes and applications 2025

Course on ``Operads, graph complexes and applications 2025''

Hybrid and Lille, France Jan.-March, 2025 By B. Fresse (Lille, France)

Poster Webpage of the course

[AHGT] Journées Galoisiennes d'Hivers 2024

Journées galoisiennes d’hiver 2024

Hybrid and Caen, France Dec. 16.-17, 2024 By B. Deschamps (Caen & Lemans, France)

Program & schedule

[AHGT] Paris Arithmetic & Homotopic Galois Theory Day 2024

Paris Arithmetic Homotopy Galois Theory Day 2024

Paris IMJ-PRG (Jussieu), France Sept. 23-24, 2024 Org.: B. Collas, E. Lepage

Workshop Poster Schedule & Program

[AHGT] Lepage AHGT RIMS lecture serie - anabelian geometry and Berkovich spaces 2024

Lecture on ``Berkovich methods for anabelian reconstructions and Resolution of Nonsingularities''

RIMS, Japan April 8, 10 and 12, 2024 By E. Lepage (IMJ Paris, France)

Schedule & Program

Anabelian Geometry in Tokyo 2024

Tokyo, Japan Mar. 11-22, 2024 Org.: Y. Taguchi, T. Murotani, N. Yamaguchi (Tokyo Inst. Tech.)

Workshop Poster Webpage of the workshop

Workshop on Model theory of valued fields and applications.

Lille Feb. 19-21, 2024 Org.: R. Cluckers (CNRS-Lille), A. Forey (CNRS-Lille), Y. Hendel (KU Leuven)

Webpage of the workshop

[AHGT] Lille Arithmetic & Homotopic Galois Theory Day 2023

Lille Arithmetic Homotopy Galois Theory Day 2023

Lille, France Oct. 10, 2023 Org.: P. Dèbes, B. Fresse

Workshop Poster Schedule & Program

Arithmetic Seminar Day in Toyonaka 2023

Osaka - Toyonaka Mar. 13, 2023 Org.: H. Nakamura

Webpage of the workshop

Young Researchers Workshops

One of the goals of the AHGT IRN is the coordination and support of independant activities for early-career researchers, i.e. Master students, PhD students and postdoctoral researchers, in terms of short and topic-focus oriented workshops and seminars.

Atelier de Géométrie Arithmétique - 数論幾何学のアトリエ

[AHGT] Atelier de Géométrie Arithmétique 2025 - Etale type

Étale homotopy type and application

Paris & RIMS Kyoto [Bridge] September 26, 2025 Org.: M. Ferreira-Filoramo, A. Galet, N. Yamaguchi

Webpage of the workshop

Spaces and perfectoids

Paris & RIMS Kyoto [Bridge] July 19, 2024 Org.: M. Ferreira-Filoramo, S. Philip & N. Takada & N. Yamaguchi

Webpage of the workshop

[Atelier24] Atelier de Géométrie Arithmétique 2024 - Around GT

Around the Grothendieck-Teichmüller group

Paris & RIMS Kyoto [Bridge] Feb. 27, 2024 Org.: M. Ferreira-Filoramo, S. Philip & N. Yamaguchi

Webpage of the workshop

[Atelier23] Atelier de Géométrie Arithmétique 2023 - Local-global principles and patching method

Local-global principles and the patching method

Paris & RIMS Kyoto [Bridge] June 27, 2023 Org.: E. Boughattas, S. Philip & N. Yamaguchi

Webpage of the workshop

The AHGT Ateliers are one-day events organized by and for early-career researchers to discover and get a working understanding of both fundamental and hot topics in Arithmetic and Homotopic Galois Theory.
Talks are distributed in advance among participants, who also propose and vote the next event topic.

Seminars for early-career researchers

Some occasional events organized by the nodes of the network:

Rational Points and Geometry at RIMS Kyoto (Aug. 10-23, 2023; 3x 2hrs) by H. Liu, IMJ-PRG.
Talk 1: Cadoret-Tamagawa’s uniform open image theorem; Talk 2: Lawrence-Venkatesh’s p-adic approach to Mordell’s conjecture; Talk 3: Fourier-Mukai transform for D-modules on complex tori.

Ookayama Youth Seminar in Algebra - 大岡山代数系若手セミナー

The Ookayama Youth Seminar in Algebra is a seminar for Mx students, and PhD and early career postdoctoral researchers of Tokyo Institute of Technology and its surrounding. The seminar takes place every two-weeks in Tokyo Institute of Technology and is organized by Slack.
Please contact the organizers T. Asayama or N. Yamaguchi.
Webpage of the Seminar

当セミナーは東京工業大学周辺の修士、博士の学生及び若手研究者を中心とした代数系のセミナーとなっております。二週に一度の頻度で開催しており、セミナー会場として東京工業大学の部屋を使用させていただいております。当セミナーはオフラインのみとなっておりますが、会場に来られる方でしたらどなたでもご参加いただけますので、ご興味のある方は主催者の浅山さんまたは山口[Contact]までご連絡ください。