IRIF, the Research Institute on the Foundations of Computer Science, is a research laboratory of CNRS and université Paris-Diderot, also hosting two INRIA project-teams.

The research conducted at IRIF is based on the study and understanding of the foundations of all computer science, in order to provide innovative solutions to the current and future challenges of digital sciences.

IRIF hosts about 200 people. Six of its members have been distinguished by the European Research Council (ERC), three are members of the Institut Universitaire de France IUF), and two are members of the Academia Europæa.

Ali Charara, director of INS2I at CNRS, visits IRIF on the morning of April 24th. The research conducted at IRIF will be presented as well as 6 specific scientific talks. The visit will be followed by a light buffet lunch.

Uri Zwick

From March 20th to May 22nd, Uri Zwick (Univ. of Tel Aviv) will give a series of 7 courses related to his FSMP Chaire of Excellence on the topic of Games on Graphs and Linear Programming Abstractions each Wednesday 2:15pm - 4:15pm at IRIF, room 3052.

We are very pleased to host as part of our IRIF Distinguished Talks Series Johan Håstad (Royal Institute of Technology, Stockholm) on April 12, 10:30 for a talk entitled “Switching lemmas in the 80ies and today”.

Two IRIF members (Ahmed Bouajjani and Pierre Fraigniaud) will give a talk at the Workshop on Taking Stock of Distributed Computing at College de France, Friday April 12.

Ile de France

The Paris Region PhD2 program will grant 30 PhD projects on Digital Sciences and with an industrial partner. IRIF is an eligible hosting lab. Call for application is open until May, 15th 2019.

Penny Haxell

Penny Haxell from University of Waterloo (Canada), a world wide expert in extremal combinatorics and graph theory, is visiting IRIF March 28th to May 2nd.
Extremal combinatorics

Extremal combinatorics studies how large or how small a collection of finite objects can be, if it has to satisfy certain restrictions. For instance, in an n-element set, what is the largest number of subsets of which none contains any other? The question is answered by Sperner's theorem, which gave rise to much of extremal set theory. Another kind of example: How many people can we invite to a party where among each three people there are two who know each other and two who don't know each other? Ramsey theory shows that at most five persons can attend such a party.
Amaury Pouly

IRIF has the great pleasure to welcome a new researcher (CNRS), Amaury Pouly, an expert in continuous models of computations, and the analysis and verification of continuous/hybrid dynamical systems.

Uri Zwick

IRIF has the great pleasure to welcome Uri Zwick, professor at the Blavantik School of Computer Sience (University of Tel-Aviv), who is visiting for four months. His stay is financed by an FSMP chair. Uri is an expert in algorithms, data structures and games. Meet him in office 4048.

(These news are displayed using a randomized-priority ranking.)

Enumerative and analytic combinatorics
Thursday April 18, 2019, 11:45AM, Salle 1007
Axel Bacher (LIPN (Paris 13)) Algorithmes de rattrapage pour la génération aléatoire de chemins

Cet exposé concerne la génération aléatoire de familles classiques de chemins (Dyck, Motzkin et Schröder et leurs préfixes). Le point de départ est l'algorithme florentin (Barcucci, Pinzani et Sprugnoli 1994+), qui utilise une méthode de rejet anticipé pour engendrer les préfixes. Je montrerai comment on peut raffiner cet algorithme en utilisant une fonction de « rattrapage » qui permet de fortement réduire, voire d'éliminer, la probabilité de rejet. Les algorithmes obtenus sont asymptotiquement optimaux en termes d'entropie utilisée et significativement plus rapides que les algorithmes florentins.

Thursday April 18, 2019, 5:30PM, In front of room 3052
Kostia Chardonnet, Ami Paz, Christine Tasson (IRIF CakeTM) Gâteau de l'IRIF

IRIF CakeTM is an amazing opportunity to meet people while simultaneously eating cakes baked by your fellow colleagues! Join us every Thursday, at 5pm, in front of room 3052 (Sophie Germain 3rd floor) for a weekly feast. You can also express your cooking skills and volunteer to bake a cake by sending an email to

Special talks
Wednesday April 24, 2019, 9AM, Amphitheater Turing
Laurent Viennot, Guillaume Chapuy, Claire Mathieu, Ahmed Bouajjani, Amaury Pouly, Constantin Enea, Yves Guiraud, Jean Krivine, Hugo Herbelin (IRIF) Scientific talk series for the visit of Ali Charara, head of INS2I at CNRS

Ali Charara, director of INS2I at CNRS, visits IRIF on the morning of April 24th. The research conducted at IRIF will be presented as well as 6 specific scientific talks.