Formalizing Higher Categories
June 8 - June 12, 2026
Higher category theory is now a fundamental aspect of modern mathematics, playing a crucial role in algebraic topology, algebraic geometry, mathematical physics, and theoretical computer science, among others. Despite its important role throughout mathematics, the inherent complexity of higher categorical methods often results in subtle errors and impedes communication with the broader mathematical community. These challenges have motivated the higher categorical community to pursue effective solutions.
One way to overcome these challenges is the formalization of higher category theory. Formalization of mathematics translates mathematical statements into a computer-programmable language, which are then verified via suitable programming languages, such as Lean or Rocq. In recent years, formalization has successfully verified crucial results in many areas of mathematics, ranging from algebra (liquid tensor experiment) to homotopy theory (homotopy type theory).
In this event, we gather experts from both areas, formalization and higher category theory, with the aim of formalizing major higher categorical results. By combining the experience and expertise from both camps, we can set formalization goals that are both relevant and feasible, bringing higher categorical knowledge to the formalization community, and conversely making tools from formalization more accessible to researchers in higher category theory. As a result of this event, we aim to significantly contribute to highe r category theory libraries. This will enable the formal verification of cutting-edge research in various applications thereof, such as homotopy theory or derived algebraic geometry.



Seminars Scroll to the next upcoming seminar
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Team ∞-Cosmos: Introducing ∞-cosmos project June 08 10:15 - 10:30 -
Team Rzk sHoTT: Introducing Rzk sHoTT project June 08 10:30 - 10:45 Team Rzk sHoTT: Introducing Rzk sHoTT project
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Team Agda sHoTT: Introducing Agda sHoTT project June 08 10:45 - 11:00 Team Agda sHoTT: Introducing Agda sHoTT project
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Team AxCat: Introducing AxCat project June 08 11:15 - 11:30 Team AxCat: Introducing AxCat project
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Team HoTTLean & CaTTLean: Introducing HoTTLean & CaTTLean project June 08 11:30 - 11:45 Team HoTTLean & CaTTLean: Introducing HoTTLean & CaTTLean project
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Team CaTT: Introducing CaTT project June 08 11:45 - 12:00 Team CaTT: Introducing CaTT project
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All teams June 08 13:30 - 14:30 All teams
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Viktoriya Ozornova: Equivalences in higher categories June 09 09:00 - 09:40 Viktoriya Ozornova: Equivalences in higher categories
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Simon Henry: Rewriting for quasicategories June 09 09:40 - 10:20 Simon Henry: Rewriting for quasicategories
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Dagur Asgeirsson: Formalizing ∞-categories for mathlib June 09 10:40 - 11:20 Dagur Asgeirsson: Formalizing ∞-categories for mathlib
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Astra Kolomatskaia: Analytic higher category theory in Narya June 09 11:20 - 12:00 Astra Kolomatskaia: Analytic higher category theory in Narya
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Formalization Session II June 09 13:00 - 15:00 Formalization Session II
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Formalization Session III June 09 15:30 - 17:00 Formalization Session III
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Bastiaan Cnossen: Synthetic Categories I June 10 09:00 - 09:30 Bastiaan Cnossen: Synthetic Categories I
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Tashi Walde: Synthetic Categories II June 10 09:30 - 10:00 Tashi Walde: Synthetic Categories II
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Ivan Kobe: Synthetic Categories III June 10 10:25 - 10:55 Ivan Kobe: Synthetic Categories III
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Bastiaan Cnossen, Tashi Walde, Ivan Kobe: Synthetic Categories Questions June 10 10:55 - 11:10 Bastiaan Cnossen, Tashi Walde, Ivan Kobe: Synthetic Categories Questions
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Formalization Session IV June 10 13:00 - 15:00 Formalization Session IV
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Formalization Session V June 10 15:30 - 17:00 Formalization Session V
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Nicolai Kraus & Simona Paoli: On Kock’s (and Sattler’s) fat Delta category June 11 09:00 - 09:50 Nicolai Kraus & Simona Paoli: On Kock’s (and Sattler’s) fat Delta category
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Sophie d’Espalungue: Rethinking Universes June 11 09:50 - 10:40 Sophie d’Espalungue: Rethinking Universes
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Amar Hadzihasanovic: alifib: a language founded on higher-dimensional rewriting June 11 11:10 - 12:00 Amar Hadzihasanovic: alifib: a language founded on higher-dimensional rewriting
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Formalization Session VI June 11 13:00 - 15:00 Formalization Session VI
Recordings
Participants
| Name | University | Country | Arrival and Departure |
|---|---|---|---|
| Carlo Angiuli (Online) | University: Indiana University | Country: United States | Arrival and Departure: |
| Dagur Asgeirsson | University: University of Alberta | Country: Canada | Arrival and Departure: |
| Steve Awodey | University: Carnegie Mellon University | Country: United States | Arrival and Departure: |
| Fredrik Bakke | University: Norwegian University of Science and Technology | Country: Norway | Arrival and Departure: |
| Cesar Bardomiano Martinez | University: University of Ottawa | Country: Canada | Arrival and Departure: |
| Reid Barton | University: University of Gothenburg and Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Andrej Bauer | University: University of Ljubljana | Country: Slovenia | Arrival and Departure: |
| Thibaut Benjamin | University: Université Paris-Saclay | Country: France | Arrival and Departure: |
| Lossin Benno (Online) | University: Technical University Munich | Country: Germany | Arrival and Departure: |
| Ulrik Buchholtz | University: University of Nottingham | Country: United Kingdom | Arrival and Departure: |
| Mario Carneiro | University: Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Evan Cavallo | University: University of Gothenburg and Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Bastiaan Cnossen | University: University of Regensburg | Country: Germany | Arrival and Departure: |
| Thierry Coquand | University: University of Gothenburg | Country: Sweden | Arrival and Departure: |
| Ishan Dasgupta Samarendra (Online) | University: University of Cambridge | Country: United Kingdom | Arrival and Departure: |
| Marco David (Online) | University: University of California, Berkeley | Country: USA | Arrival and Departure: |
| Sophie d'Espalungue | University: Université Paris Cité | Country: France | Arrival and Departure: |
| Amartya Dubey (Online) | University: National Institute of Science Education and Research | Country: India | Arrival and Departure: |
| Aras Ergus (Online) | University: TNG Technology Consulting | Country: Germany | Arrival and Departure: |
| Eric Finster | University: University of Birmingham | Country: United Kingdom | Arrival and Departure: |
| Nicola Gambino (Online) | University: University of Manchester | Country: United Kingdom | Arrival and Departure: |
| Johannes Gloßner (Online) | University: University of Regensburg | Country: Germany | Arrival and Departure: |
| Daniel Gratzer | University: Aarhus University | Country: Denmark | Arrival and Departure: |
| Håkon Robbestad Gylterud | University: University of Bergen | Country: Norway | Arrival and Departure: |
| Amar Hadzihasanovic | University: Tallinn University of Technology | Country: Estonia | Arrival and Departure: |
| Rida Hamadani (Online) | University: Université de Pau et des Pays de l'Adour (UPPA) | Country: France | Arrival and Departure: |
| Rune Haugseng | University: Norwegian University of Science and Technology | Country: Norway | Arrival and Departure: |
| Sina Hazratpour | University: Stockholm University | Country: Sweden | Arrival and Departure: |
| Simon Henry | University: University of Ottawa | Country: Canada | Arrival and Departure: |
| Jonas Höfer | University: Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Vyom Kamboj (Online) | University: Kansas State University | Country: United States/Germany | Arrival and Departure: |
| Arash Karimi (Online) | University: Florida State University | Country: United States | Arrival and Departure: |
| Ivan Kobe | University: University of Ljubljana | Country: Slovenia | Arrival and Departure: |
| Astra Kolomatskaia | University: Wesleyan University | Country: United States | Arrival and Departure: |
| Nicolai Kraus | University: University of Nottingham | Country: United Kingdom | Arrival and Departure: |
| Nikolai Kudasov (Online) | University: Innopolis University | Country: Russia | Arrival and Departure: |
| Julian Külshammer | University: Uppsala University | Country: Sweden | Arrival and Departure: |
| Yun Liu (Online) | University: Indiana University Bloomington | Country: United States | Arrival and Departure: |
| Peter LeFanu Lumsdaine | University: Stockholm University | Country: Sweden | Arrival and Departure: |
| Stefano Luneia (Online) | University: University of Ottawa | Country: Canada | Arrival and Departure: |
| David Martínez-Carpena (Online) | University: University of Barcelona | Country: Spain | Arrival and Departure: |
| Udit Ajit Mavinkurve (Online) | University: Indian Institute of Technology Bombay | Country: India | Arrival and Departure: |
| Jack McKoen | University: University of Alberta | Country: Canada | Arrival and Departure: |
| Antonio Michele Miti (Online) | University: Università di Roma la Sapienza | Country: Italy | Arrival and Departure: |
| Lyne Moser | University: University of Regensburg | Country: Germany | Arrival and Departure: |
| Anders Mörtberg | University: Stockholm University | Country: Sweden | Arrival and Departure: |
| Javad Najjarzadeh (Online) | University: Tarbiat Modares University | Country: Iran | Arrival and Departure: |
| Paige Randall North (Online) | University: Utrecht University | Country: Netherlands | Arrival and Departure: |
| Andreas Nuyts | University: KU Leuven | Country: Belgium | Arrival and Departure: |
| Viktoriya Ozornova | University: Max Planck Institute for Mathematics | Country: Germany | Arrival and Departure: |
| Simona Paoli | University: University of Aberdeen | Country: United Kingdom | Arrival and Departure: |
| Nima Rasekh | University: University of Greifswald | Country: Germany | Arrival and Departure: |
| Robert Rennie (Online) | University: Hampden-Sydney College | Country: U.S.A | Arrival and Departure: |
| Emily Riehl | University: Johns Hopkins University | Country: United States | Arrival and Departure: |
| Joël Riou | University: University Paris-Saclay | Country: France | Arrival and Departure: |
| Takafumi Saikawa (Online) | University: Nagoya University | Country: Japan | Arrival and Departure: |
| Christian Sattler | University: Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Quentin Schroeder (Online) | University: Université Sorbonne Paris Nord | Country: France | Arrival and Departure: |
| Luuk Stehouwer (Online) | University: Durham University | Country: United Kingdom | Arrival and Departure: |
| Chaitanya Leena Subramaniam (Online) | University: Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Samuel Toth (Online) | University: University of Nottingham | Country: United Kingdom | Arrival and Departure: |
| Miika Tuominen (Online) | University: University of Virginia | Country: United States | Arrival and Departure: |
| Pavel Turyansky (Online) | University: Kaspersky Lab R&D | Country: Russia | Arrival and Departure: |
| Emilie Uthaiwat (Online) | University: Aix-Marseille Université | Country: France | Arrival and Departure: |
| Dominic Verity | University: Australian National University | Country: Australia | Arrival and Departure: |
| Tashi Walde | University: University of Regensburg | Country: Germany | Arrival and Departure: |
| Jonathan Weinberger | University: Chapman University | Country: United States | Arrival and Departure: |
| David Wärn | University: Chalmers University of Technology | Country: Sweden | Arrival and Departure: |
| Wenrong Zou (Online) | University: University of Bonn | Country: Germany | Arrival and Departure: |