tcs ryuya and nicolas

_data/tcs.yml

+- date: 2025-06-17T16:00+01
+  room: Henri Poincaré
+  speaker: Nicolas Blanco
+  lab: CEA Paris-Saclay
+  title: "TBD"
+  abstract: TBD
 - date: 2025-06-11T16:00+01
   room: Henri Poincaré
   speaker: Ryuya Hora
   lab: University of Tokyo
-  title: "TBD"
+  title: "A topos for regular language theory"
   abstract: |
-    TBD
+    A. Grothendieck introduced the notion of a topos in order to bring continuous geometric methods into number theory, which had been regarded as a finite and discrete subject. Topoi, or at least their presentation as sites, have since become a foundational tool in modern number theory.
+
+    Automata theory and the theory of regular languages are also usually regarded as finite and discrete. But is it possible to bring continuous geometric methods into this setting as well? For example, can we construct a space (i.e., a topos) that fully encodes the information of regular languages, and then speak of its points, subspaces, quotients, local connectedness, cohomology, or (profinite) fundamental group?
+
+    In this talk, I will present one such construction of a “space of regular languages” (as a connected and locally connected topos!) and introduce its various presentations and properties. This talk is based on Topoi of Automata I (https://arxiv.org/abs/2411.06358) and its ongoing sequel, Topoi of Automata II.
 - date: 2025-04-08T16:00+01
   room: Henri Poincaré
   speaker: Quentin Aristote