[TYPES/announce] Proof Society seminar: Anton Freund, 15 December 2025

[Marianna Girlando]

Dear all,

The next Proof Society Seminar will take place on Monday, 15 December 2025, at 14:00 CET / 13:00 UTC. Our speaker will be Anton Freund, from the University of Wuerzburg. Details can be found below.

The Proof Society Seminar<https://urldefense.com/v3/__https://www.proofsociety.org/proof-society-seminar/__;!!IBzWLUs!UcdWFxpH2e7gZnXTEO_3ANKIcs1AKDLAyN-tfOtBPVaCzQ0FE1LF0QkjqTb0KU58LlWh-d7-TEHmOVILgyhRpHMv4AW5pF9FHQ$ > is the official seminar of the Proof Society, and it presents talks by leading researchers from all areas of proof theory. Everyone who is interested in the subject is warmly invited to attend! The talks take place online via Zoom, usually on Mondays, approximately once per month. They start at 13:00 UTC and may last up to 75 minutes plus questions.

Kind regards,
Lev Beklemishev
Anupam Das
Marianna Girlando


---- Proof Society Seminar, Monday 15.12.2025, 14:00 CET ----

Anton Freund (Wuerzburg University): Approaching Girard's functor Lambda

Abstract: Girard has claimed that Pi^1_1-comprehension corresponds to his functor Lambda on dilators. He described a plausible proof around 1980, but it seems that details remain difficult. This talk presents joint work with Aguilera and Weiermann, in which we give a detailed proof that Pi^1_1-comprehension corresponds to a variant of Lambda, namely the functor J of Päppinghaus. No prior knowledge of dilators is assumed.

The seminar takes place via Zoom:
https://bham-ac-uk.zoom.us/j/84261727269 
Meeting ID: 842 6172 7269


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://LISTS.SEAS.UPENN.EDU/pipermail/types-announce/attachments/20251203/38de977a/attachment-0001.htm>