March 2026 - Categories - Listes du LIPN

GdT demain
by Groupe de travail catégories 27 Mar '26

27 Mar '26

Hi, Yiming asked me to tell you that her talk will actually mostly be about sheaf topoi and maps between them; Leo will tell us more about relative topos theory next week. See you tomorrow! Best wishes, Morgan

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My talk yesterday, GdT this week
by Groupe de travail catégories 26 Mar '26

26 Mar '26

Hi! In case you missed it, here is a link to my talk yesterday: https://www.youtube.com/watch?v=0d9O7W42zHw And a link to the BBB where you can find Ulrich's first talk: https://bbb.math.univ-paris13.fr/b/chr-hyw-0rb-jz4 This Friday at 10:30am in B107, Yiming Xu will talk to us about relative topos theory. I hope to see many of you there! Best wishes, Morgan

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Talk at the NYC category theory seminar
by Groupe de travail catégories 25 Mar '26

25 Mar '26

Fyi I'm speaking from now! See you there, maybe. Morgan

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Re: [GdT Categories] visite Ulrik BUCHHOLTZ & mini-course HoTT
by Groupe de travail catégories 22 Mar '26

22 Mar '26

Bonsoir, Ulrik Buchholtz’s HoTT mini-course is scheduled for the next three Wednesdays (March 25, April 1, and April 8), from 16:00 to 18:00 at Paris 13 University in Villetaneuse. The abstract is below. The room will be announced soon. We look forward to seeing many of you, and please feel free to forward this announcement. Best regards, Jonas Title : Introduction to Synthetic Homotopy Theory Abstract : We'll cover topics in synthetic homotopy theory using homotopy type theory/univalent foundations. First, we'll give a brief overview of Martin-Löf type theory and an intuitive picture of its interpretation in spaces qua infinity-groupoids. This interpretation motivates Voevodsky's definition of contractible types, equivalences, homotopy n-types, n-connected types, and the univalence axiom. Next, we cover homotopy pushouts as a new type constructor, including variations such as the circle, suspensions, cofibers, joins, and smash products. We'll look at the type-theoretic formulation of homotopy groups, and the long exact sequence given by a map, leading to the calculation of some homotopy groups. The last lecture will cover the zigzag construction of the path spaces of pushouts, leading to a type-theoretic proof of the Blakers–Massey connectivity theorem. Time permitting, we can touch on other aspects of synthetic homotopy theory, according to the interests of the participants. On 3/17/26 16:15, Jonas Frey wrote: > > Bonjour, > > Notre invité *Ulrik Buchholtz* arrivera lundi prochain (23 mars) et > restera jusqu'au 26 avril avec une interruption d'une semaine (du 12 > au 18 avril). En tant qu'invité de l'EUR > <https://eur.univ-paris13.fr/> il donnera un mini-cours d'environ > trois séances sur la *théorie homotopique de types* (HoTT) destiné aux > étudiants de master, mais aussi aux doctorants, postdocs et > permanents. Si ça vous intéresse vous et invités à remplir ce sondage > <https://lettucemeet.com/l/KwWpn> pour indiquer vos disponibilités. > > Dear all, > > Our guest *Ulrik Buchholtz* will be arriving next Monday (*March 23*) > and will be staying until *April 26*, with a one-week break from April > 12 to 18. As a guest of the EUR <https://eur.univ-paris13.fr/>, he > will give a mini-course of about three sessions on *Homotopy Type > Theory (HoTT)*. This course is *aimed at* Master’s students, but PhD > students, postdocs, and permanent staff are also welcome to attend. > > If you are interested, you are invited to fill out this poll > <https://lettucemeet.com/l/KwWpn> to indicate your availability. > > Best, > > Jonas >

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GdT demain
by Groupe de travail catégories 20 Mar '26

20 Mar '26

Hi! It's been plenty of time, so even with no specific plan, I'll announce that we'll have a GdT tomorrow in B107 at 10:30am as usual. If Christian can't do the talk which was planned for last week that we had to cancel, maybe I'll tell you all about my understanding of relative monads! I'll set up the BBB at the usual link too. Best wishes, Morgan

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visite Ulrik BUCHHOLTZ & mini-course HoTT
by Groupe de travail catégories 17 Mar '26

17 Mar '26

Bonjour, Notre invité *Ulrik Buchholtz* arrivera lundi prochain (23 mars) et restera jusqu'au 26 avril avec une interruption d'une semaine (du 12 au 18 avril). En tant qu'invité de l'EUR <https://eur.univ-paris13.fr/> il donnera un mini-cours d'environ trois séances sur la *théorie homotopique de types* (HoTT) destiné aux étudiants de master, mais aussi aux doctorants, postdocs et permanents. Si ça vous intéresse vous et invités à remplir ce sondage <https://lettucemeet.com/l/KwWpn> pour indiquer vos disponibilités. Dear all, Our guest *Ulrik Buchholtz* will be arriving next Monday (*March 23*) and will be staying until *April 26*, with a one-week break from April 12 to 18. As a guest of the EUR <https://eur.univ-paris13.fr/>, he will give a mini-course of about three sessions on *Homotopy Type Theory (HoTT)*. This course is *aimed at* Master’s students, but PhD students, postdocs, and permanent staff are also welcome to attend. If you are interested, you are invited to fill out this poll <https://lettucemeet.com/l/KwWpn> to indicate your availability. Best, Jonas

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Pas de GdT aujourd'hui
by Groupe de travail catégories 13 Mar '26

13 Mar '26

Hi! To save potential needless travel, there will be no GdT today. Starting months ago, a colleague had planned a workshop today under the assumption that rooms in the new building would be functional (which they are not), so I accepted to give up our room booking. Best wishes, Morgan

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