Mardi 12 Mars
Heure: 
12:30  13:30 
Lieu: 
Salle B107, bâtiment B, Université de Villetaneuse 
Résumé: 
Reverse ChvatalGomory rank. 
Description: 
Roland Grappe We introduce the reverse ChvatalGomory rank r*(P) of an integral polyhedron P, defined as the supremum of the ChvatalGomory ranks of all rational polyhedra whose integer hull is P. A wellknown example in dimension two shows that there exist integral polytopes P with r*(P) infinite. We provide a geometric characterization of polyhedra with this property in general dimension, and investigate upper bounds on r*(P) when this value is finite. This is a joint work with Michele Conforti, Alberto Del Pia, Marco Di Summa and Yuri Faenza.&nbsp; 
Heure: 
14:00  17:00 
Lieu: 
Salle B107, bâtiment B, Université de Villetaneuse 
Résumé: 
Bipartite subfamilies of planar graphs 
Description: 
Juanjo Rué Perna I will survey the techniques used to get asymptotic results for subfamilies of planar graphs, as well as how to relate this methodology with the context of map enumeration. In the second part of the talk, I willexplain the ideas behind some ongoing projects related to the enumeration of bipartite subfamilies of graphs. 
Vendredi 15 Mars
Heure: 
13:30  14:30 
Lieu: 
Salle B107, bâtiment B, Université de Villetaneuse 
Résumé: 
Linear Dependent Types For Differential Privacy 
Description: 
Marco Gaboardi Differential privacy offers a way to answer queries about sensitive information while offering strong, provable privacy guarantees. Several tools have been developed for certifying that a given query is differentially private. In one approach, Reed and Pierce[31] proposed a functional programming language, Fuzz, for writing differentially private queries. Fuzz uses linear types to track sensitivity, as well as a probability monad to express randomized computation; it guarantees that any program that has a certain type is differentially private. Fuzz can successfully verify many useful queries. However, it fails when the analysis depends on values that are not known statically. We present DFuzz, an extension of Fuzz with a combination of linear indexed types and lightweight dependent types. This combination allows a richer sensitivity analysis that is able to analyze a larger class of queries, including queries whose sensitivity depends on runtime information. As in Fuzz, the differential privacy guarantees follows directly from the soundness theorem for the type system. We demonstrate the enhanced expressivity of DFuzz by certifying differential privacy a broad class of iterative algorithms that could not be typed previously. We conclude by discussing the challenges of DFuzz type checking. 

