Mardi 19 Novembre
Heure: 
12:00  13:30 
Lieu: 
Salle B107, bâtiment B, Université de Villetaneuse 
Résumé: 
Line graphs and Facility Location Problem 
Description: 
Laurent Beaudou (This is a joint work with M. Baïou, Z. Li and V. Limouzy) The line graph of a digraph can be defined in a few different ways. One of them came naturally from our study of a facility location problem. We discuss the complexity of recognizing such graphs and their cousins. During this seminar, we shall also have an overview of the historical birth of facility location problems. 
Heure: 
14:00  17:00 
Lieu: 
Salle B107, bâtiment B, Université de Villetaneuse 
Résumé: 
Cartography on unoriented surfaces, with applications to real and quaternionic random matrices 
Description: 
Emily Redelmeier I will discuss the cartographic machinery (encoding of mapson surfaces by permutations) on unoriented surfaces. I will discusshow these appear in calculations with real and quaternionic randommatrices, and their connections with other combinatorial objectsassociated with these objects, such as the hyperoctahedral group andmatricial cumulants. I will present some results in asymptoticsecondorder freeness which may be approached using these objects. 

