Rencontres de rentrée

lundi 28 sept. 2026, 11:30 → 16:00 Europe/Paris

Salle Maryam Mirzakhani (IHP - Bâtiment Borel)

Nous avons le plaisir de vous annoncer la reprise du NP-coi pour l'année 2026-2027. 

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La journée de rentrée aura lieu le lundi 28 septembre à l'IHP (Institut Henri Poincaré).

N'oubliez pas de vous inscrire pour le repas. 

11:30 → 12:00 Boîte à outils pour une thèse en combinatoire

12:00 → 13:30 Repas / Buffet

13:30 → 14:30 Marguerite Bin - From Cubes to Tilings and Chirotopes, from Hypersimplices to k-levels and k-sets

A tiling of a zonogon by rhombi is called coherent if it corresponds to the visible faces of a zonotope in R^3. The problem of deciding whether a tiling is coherent is known to be difficult (in particular, it is NP-hard and ETR-complete). If we restrict ourselves to partial information about the tiling, such as its k-level, does the problem remain difficult? By interpreting this information geometrically, we will provide some answers to this question.

14:30 → 15:30 Ludovic Schwob : From middle orders to Jurassian lattices

The weak and Bruhat orders are well-studied posets on Coxeter groups. In a recent paper, we introduced middle orders, which are distributive lattices between the weak and Bruhat orders, describing all middle orders on the symmetric group, and a generalization of these on Weyl groups called minuscule middle orders. In this talk, I will explain how Jurassian lattices can be constructed from minuscule middle orders. These lattices share a lot of properties with Cambrian lattices, such as being congruence-uniform and extremal, having size Catalan(W), or being the 1-skeleton of a regular polytope.

15:30 → 16:00 Moment convivial