Institut de Recherche en Informatique Fondamentale(IRIF)


IRIF, the Research Institute on the Foundations of Computer Science, is a research laboratory of CNRS and Université de Paris, also hosting one Inria project-team.

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), five are members of the Institut Universitaire de France IUF), two are members of the Academia Europæa, and one is member of Académie des sciences.

Accepted papers STACS 2022

Two papers coauthored by IRIF members will be presented at the 39th International Symposium on Theoretical Aspects of Computer Science (STACS 2022) held in Marseille, March 15-18 2022.

Accepted paper FOCS 2021

Adrian Vladu's paper Faster Sparse Minimum Cost Flow by Electrical Flow Localization, jointly written with Kyriakos Axiotis and Aleksander Madry, will be presented at FOCS 2021.


IRIF is very pleased to host for two months Serge Massar, Professor at the Université libre de Bruxelles (ULB) as part of the FSMP Distinguished Professor Fellowship. Serge Massar is the director of the Laboratoire d'Information Quantique (LIQ), of the Physics Department, Science Faculty, ULB. His research interests are quantum information theory, experimental quantum and non linear optics, machine learning.


Prochaine conférence dans le cadre des 75 ans d’informatique : L’informatique dans le 7ème art : fiction ou réalité ? Rendez-vous avec Fabrice Kordon le jeudi 9 décembre-18h00 sur le campus Pierre et Marie Curie de Sorbonne Université (tour 25.26, 1er étage – salle 105).

Accepted paper POPL 2022

Delia Kesner (IRIF) will present her paper A Fine-Grained Computational Interpretation of Girard’s Intuitionistic Proof-Nets at annual Symposium on Principles of Programming Languages, POPL2022. The paper introduces a functional term calculus that captures the essence of the operational semantics of Intuitionistic Linear Logic Proof-Nets with a faithful degree of granularity, both statically and dynamically.

Accepted paper POPL 2022

Paul-André Melliès (IRIF), Arthur Vale, Zhong Shao, Jérémie Koenig (Yale) and Léo Stefanesco (MPI) will present a layered concurrent object-based game semantics for the purpose of compositional software specification and certification at annual Symposium on Principles of Programming Languages, POPL2022 :

IFIP nomination fellow

Jacques Sakarovitch (IRIF) was elected new IFIP Fellow. IFIP Fellow is the most most prestigious IFIP's technical distinction which is conferred by the IFIP General Assembly on a current or past member of an IFIP body in recognition of outstanding contributions in the field of information processing, in the role of a Technical Leader, Scientist, Engineer, or Educator.

hpcqs project

We are excited to be part of the “High-Performance Computer and Quantum Simulator hybrid” (HPCQS) aiming at creating a world-class supercomputing ecosystem. Learn more about the project here.

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

Enumerative and analytic combinatorics
Thursday January 20, 2022, 2PM, Salle 3052 et sur zoom
Noémie Cartier (Université de Paris-Saclay) Lattice properties of acyclic pipe dreams

A pipe dream is a collection of pipes that trace the values of a permutation when passing through a sorting network. By choosing the sorting network and the permutation carefully, the set of reduced pipe dreams gives a realization of the Tamari lattice, a famous lattice quotient of the weak order. The talk will present a generalization of this result: if our sorting network respects a few specific properties, the set of reduced and acyclic pipe dreams of a permutation is a lattice quotient of an interval of the weak order.

Proofs, programs and systems
Thursday January 20, 2022, 10:15AM, Virtual room at link
Bruno Dinis (Universidade de Lisboa) Functional interpretations and applications

Functional interpretations are maps of formulas from the language of one theory into the language of another theory, in such a way that provability is preserved. These interpretations typically replace logical relations by functional relations. Functional interpretations have many uses, such as relative consistency results, conservation results, and extraction of computational content from proofs as is the case in the so-called proof mining program.

I will present several recent functional interpretations and some results that come from these interpretations. I will also give examples of application of functional interpretations, in the spirit of the proof mining program.

Friday January 21, 2022, 2:30PM, Salle 3052
Victor Marsault Demonstration of Awali 2.1, a library for weighted automata and transducers.

Awali is a software suite for computing with finite weighted automata and transducers with any number of tapes. Many algorithms are implemented including most of the classical ones. Automata and transducers may be weighted over a classical number sets (N,Z,Q,R,C,Z/nZ) but also over several other weightsets (such as the tropical semirings).

Awali may be accessed in C++ (awalidyn, or directly using templates) or in Python (awalipy). Awali can also be used interactively from its command-line interface (Cora) or using awalipy together with Jupyter, a top-level Python interpreter.

Awali may be downloaded from and I'll be happy to address possible installation issues after the presentation.

Algorithms and complexity
Tuesday January 25, 2022, 2PM, 3052
Simona Etinski (INRIA / IRIF) Latest challenges in post-quantum cryptography

In 2016, the National Institute of Standards and Technology (NIST) announced a call for standardization (also known as “NIST competition”) of post-quantum cryptographic protocols, i.e., cryptographic protocols considered to be resistant to quantum attacks. NIST was mainly interested in two types of protocols: digital signatures and encryption/key-establishment schemes. The fourth and final round of this competition is about to start, and once it is finished, the most efficient and thoroughly analyzed protocols will be standardized.

In this talk, we focus on the proposal for a digital signature. It is based upon a problem from coding theory, known as a syndrome decoding problem, and analyzed using cryptanalytic means. Namely, we analyze the time complexity of the information set decoding algorithms, widely believed to be the best algorithms for solving the syndrome decoding problem. By evaluating their complexity, both in the classical and quantum domain, we reason about the hardness of the problem. Finally, we give an example of the scheme based upon the syndrome decoding problem and analyze its security imposed by the hardness of the problem. We examine the tradeoff between signature's security and its size, which is a major challenge to be addressed in the competition.

One world numeration seminar
Tuesday January 25, 2022, 2:30PM, Online
Claudio Bonanno (Università di Pisa) Infinite ergodic theory and a tree of rational pairs

The study of the continued fraction expansions of real numbers by ergodic methods is now a classical and well-known part of the theory of dynamical systems. Less is known for the multi-dimensional expansions. I will present an ergodic approach to a two-dimensional continued fraction algorithm introduced by T. Garrity, and show how to get a complete tree of rational pairs by using the Farey sum of fractions. The talk is based on joint work with A. Del Vigna and S. Munday.

Enumerative and analytic combinatorics
Thursday January 27, 2022, 2PM, Salle 3052 et sur zoom
Elba Garcia-Failde (IMJ-PRG Sorbonne Universite) TBD

Proofs, programs and systems
Thursday January 27, 2022, 10:30AM, TBA
Titouan Carette (LORIA / Université de Lorraine) To be announced.

Graph Transformation Theory and Applications
Friday January 28, 2022, 3PM, online
William Waites (University of Strathclyde, Scotland, UK) Rule-based Models of Epidemics

Rule-based models, a particular kind of graph rewriting system initially intended for use in molecular biology, are conspicuously useful for understanding epidemics. They enable formulation of complex processes that blends the ease of understanding of “compartmental” models with the expressiveness of individual- or agent-based models. We illustrate this with a story, told in graph rewriting rules, of how the adaptive immune response to a pathogen works (simplified version) and how this response influences the population level dynamics of an epidemic. This model can be calibrated against real-world data and we see how some of the individual heterogeneity that is normally treated phenomenologically in the study of epidemics arises naturally from this account of immune response.

Zoom meeting registration link

YouTube live stream

Enumerative and analytic combinatorics
Thursday February 3, 2022, 2PM, Salle 1007
Seminaire Flajolet d

Friday February 4, 2022, 2:30PM, Salle 3052 (Online)
Bartek Klin Orbit-finite-dimensional vector spaces, with applications to weighted register automata

I will discuss vector spaces spanned by orbit-finite sets. These spaces are infinite-dimensional, but their sets of dimensions are so highly symmetric that the spaces have many properties enjoyed by finitely-dimensional spaces.

Applications of this include a decision procedure for equivalence of weighted register automata, which are the common generalization of weighted automata and register automata for infinite alphabets. The algorithm runs in exponential time, and in polynomial time for a fixed number of registers. As a special case, we can decide, with the same complexity, language equivalence for unambiguous register automata.

(Joint work with Mikołaj Bojańczyk and Joshua Moerman.)