May 2025 - Categories - Listes du LIPN

Exposé dans 25 minutes
by Groupe de travail catégories 28 May '25

28 May '25

Salut! Je donne un exposé sur les morphismes géométriques à l'IRIF à 14h. Voici un bien pour suivre en visio. https://galene.org:8443/group/moreau/?token=f5UH0R17C1E A+ Morgan

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GdT demain
by Groupe de travail catégories 28 May '25

28 May '25

Sorry for the late message. We should have a meeting tomorrow morning as usual. Having recently reviewed the material, I intend to complement Jonas' past two weeks with an explanation of how classifying toposes can be constructed. BBB link: https://bbb.lipn.univ-paris13.fr/b/rog-vao-uwm-s2j We should start and end more promptly than usual since I am giving a talk at the /Sheaves in Geometry and Logic /reading group at IRIF at 2pm in the afternoon about geometric morphisms. See you tomorrow! Morgan

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GdT demain
by Groupe de travail catégories 20 May '25

20 May '25

Hi, Jonas has offered to continue his presentation of classifying toposes tomorrow. We will meet at 10:30am in B107 as usual, and on BBB: https://bbb.lipn.univ-paris13.fr/b/rog-vao-uwm-s2j See you there, Morgan

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GdT demain
by Groupe de travail catégories 13 May '25

13 May '25

Hello! Tomorrow we will meet at 10:30am in B107. BBB link: https://bbb.lipn.univ-paris13.fr/b/rog-vao-uwm-s2j Last week I gave an introduction to categorical semantics, explaining the standard way that formulas-in-context are interpreted as subobjects, allowing us to interpret "geometric formulas" in any (Grothendieck) topos, and hence define models of "geometric theories". This background can be found in much more detail in chapters D1.1-1.3 of Johnstone's Sketches of an Elephant, or Caramello's Theories, Sites, Toposes. Let me know if you want access to a copy of either of those. This week, Jonas will pick up where I left off, with the aim of explaining what a classifying topos is. I will remember to record this session! See you there, Morgan

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Meeting today (BBB link)
by Groupe de travail catégories 07 May '25

07 May '25

Hello again, My previous email was the late announcement of a shortened working group meeting today in B107 starting at 11:00 a.m (note the later start time). This will be an informal session to establish the basic knowledge of the interested parties on the classification topos and/or the internal language of the topos. Here is the BBB link for anyone wishing to join online: https://bbb.lipn.univ-paris13.fr/b/rog-vao-uwm-s2j See you soon, Morgan

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GdT aujourd'hui
by Groupe de travail catégories 07 May '25

07 May '25

Bonjour, Désolé pour l'annonce tardive. Nous allons tenir une séance raccourci du GdT aujourd'hui en B107 à partir de 11h. Ce sera une séance informel pour établir les connaissances de base des intéressés sur les topos classifiants et/ou le langage interne des topos. J'envoie un lien BBB quand j'arrive au LIPN. À bientôt, Morgan

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