L'IRIF est une unité mixte de recherche (UMR 8243) entre le CNRS et l'Université Paris-Diderot, qui héberge deux équipes-projets INRIA.

Les recherches menées à l'IRIF reposent sur l’étude et la compréhension des fondements de toute l’informatique, afin d’apporter des solutions innovantes aux défis actuels et futurs des sciences numériques.

L'IRIF regroupe près de deux cents personnes. Six de ses membres ont été lauréats de l'European Research Council (ERC), trois sont membres de l'Institut Universitaire de France (IUF) et deux sont membres de l'Academia Europæa.

19.11.2018
IRIF has the great pleasure to welcome Mahsa Shirmohammadi, researcher scientist (CNRS) from LIS, who is visiting IRIF for six months and who is an expert in the analysis and verification of timed, counter and probabilistic systems.

9.12.2018
The Alexander von Humboldt Foundation has honored Ahmed Bouajjani (IRIF) with the prestigious Carl Friedrich von Siemens Research Award, in recognition of his research contributions.

13.12.2018
Constantin Enea (IRIF) will present at POPL 2019 a methodology for specifying software modules whose operations satisfy multiple consistency levels. This work has revealed previously unknown documentation errors and bugs in Java concurrent objects.

20.11.2018
One paper coauthored by Laurent Feuilloley while he was PhD student at IRIF will be presented at SODA’19, the main conference in algorithm design. The paper provides lower bounds for the fundamental problem of text indexing with mismatches and differences using the Strong Exponential Time Hypothesis.

7.10.2018
Jean-Eric Pin, CNRS senior researcher at IRIF, is awarded the Arto Salomaa prize for his outstanding contribution to the field of Automata Theory.

3.12.2018
Maybe you are an eager bitcoin miner? Maybe you are a fan of quantum computing too, and you wonder what will change in the mining competition when done by quantum computers? Find some answers in a paper coauthored by Miklos Santha (IRIF) to be presented at ITCS’19.

29.11.2018
Constantin Enea from IRIF organizes with Ruzica Piskac (Yale University), the 20th International Conference on Verification, Model Checking, and Abstract Interpretation (VMCAI 2019). The conference is preceded by a winter school on formal methods.

20.11.2018
Two papers coauthored by IRIF members will be presented at QIP’19, the main conference for theoretical quantum information research. Topics include efficient quantum algorithms for both algebraic and distributed problems.

Graphes
mardi 18 décembre 2018, 15h30, Salle 3052
Bergougnoux Benjamin (IRIF) Rank Based Approach on Graphs with Structured Neighborhood

In this talk, I will present a framework combining the rank-based approach with the notion of $d$-neighbor equivalence. The rank-based approach is a technique introduced by Bodlaender et al. in 2015 to obtained $2^{O(k)}\cdot n$ time algorithms, $k$ the treewidth of the input graph, for a wide range of connectivity problems.

The $d$-neighbor equivalence is a tools introduced by Bui-Xuan et al. in 2013 to obtained efficient parameterized algorithms for many width measures (clique-width, rank-width, mim-width,…) and for many problems with a locally checkable constraint (Dominating Set, Independent Set,…).

By combining these two notions, we obtain efficient algorithms for several connectivity problems such as Connected Dominating Set, Node Weighted Steiner Tree, Maximum Induced Tree, Longest Induced Path, and Feedback Vertex Set. For all these problems, we obtain $2^{O(k)}\cdot n^{O(1)}$, $2^{O(k \log(k))}\cdot n^{O(1)}$, $2^{O(k^2)}\cdot n^{O(1)}$ and $n^{O(k)}$ time algorithms parameterized respectively by clique-width, $\mathbb{Q}$-rank-width, rank-width and maximum induced matching width. Our approach simplifies and unifies the known algorithms for each of the parameters and match asymptotically also the best time complexity for Vertex Cover and Dominating Set.

Paper available on HAL : https://hal.archives-ouvertes.fr/hal-01799573v2/document

Combinatoire énumérative et analytique
jeudi 20 décembre 2018, 11h45, Salle 1007
Cyrille Chenavier (INRIA (Lille)) Quotients of the magmatic operad: lattice structures and convergent rewrite systems

Automates
vendredi 21 décembre 2018, 14h30, Salle 3052
Jérôme Leroux (LaBRI) The Reachability Problem for Petri Nets is Not Elementary

Petri nets, also known as vector addition systems, are a long established and widely used model of concurrent processes. The complexity of their reachability problem is one of the most prominent open questions in the theory of verification. That the reachability problem is decidable was established by Mayr in his seminal STOC 1981 work, and the currently best upper bound is non-primitive recursive cubic-Ackermannian of Leroux and Schmitz from LICS 2015. We show that the reachability problem is not elementary. Until this work, the best lower bound has been exponential space, due to Lipton in 1976.

Joint work with Wojciech Czerwinski, Slawomir Lasota, Ranko Lazic, Filip Mazowiecki.