News & Events
PhD Defence: Glen Mével
Cosmo: a concurrent separation logic for the weak memory of Multicore OCaml
by Glen Mével
Wednesday 14 December 2022 at 2pm
Inria Paris,. 2 rue Simone Iff, Paris, Salle Lions 1, and online
Abstract: Multicore OCaml extends OCaml with support for shared-memory concurrency. It is equipped with a weak memory model, for which an operational semantics has been published. This begs the question: what reasoning rules can one rely upon while writing or verifying Multicore OCaml code?
To answer it, we instantiate Iris, a modern descendant of Concurrent Separation Logic, for Multicore OCaml. This yields a low-level program logic whose reasoning rules expose the details of the memory model. On top of it, we build a higher-level logic, Cosmo, which trades off some expressive power in return for a simple set of reasoning rules that allow accessing non-atomic locations in a data-race-free manner, exploiting the sequentially-consistent behavior of atomic locations, and exploiting the release/acquire behavior of atomic locations. Cosmo allows both low-level reasoning, where the details of the Multicore OCaml memory model are apparent, and high-level reasoning, which is independent of this memory model.
PhD Defence: Amrita Suresh
Formal Verification of Communicating Automata
by Amrita Suresh
Monday 12 December 2022 at 2pm
Room 1Z18, ENS Paris-Saclay and online
Abstract: Distributed systems involve processes that run independently and communicate asynchronously. While they capture a wide range of use cases and are hence, ubiquitous in our world, it is also particularly difficult to ensure their correctness.
In this thesis, we model such systems using mathematical and logical formulation, and try to verify them algorithmically. In particular, we focus on FIFO (First-In First-Out) machines, with one or more finite-state machines communicating via unbounded reliable FIFO buffers. Read more...
PhD Defence: Mathieu Hilaire
Parity games and reachability in infinite-state systems with parameters
by Mathieu Hilaire
Thursday 13 December 2022 at 9am
Room 1Z71, ENS Paris-Saclay and online
Abstract: The most standard model checking approaches are limited to verifying concrete specifications, such as “can we reach a configuration with more than 10 time units elapsing ?”. Nevertheless, for certain computer programs, like embedded systems, the constraints depend on the environment. Thus arises the need for parametric specifications, such as “can we reach a configuration with more than p time units elapsing ?” where p is a parameter which takes values in the non-negative integers.
In this thesis, we study parametric pushdown, counter and timed automata and extensions thereof. In addition to expressing concrete constraints (on the stack, on the counter or on clocks), these can employ parametric constraints. The reachability problem for a parametric automaton asks for the existence of an assignment of the parameters such that there exists an accepting run in the underlying concrete automaton. In addition to the reachability problem, we consider parametric parity games, two player games where players alternate choosing assignments for each parameters, then alternate moving a token along the configurations of the concrete automaton resulting from their choice of parameter assignment. We consider the problem of deciding which player has a winning strategy.
Best Process-Mining Dissertation Award for Mathilde Boltenhagen
Mathilde Boltenhagen received the Best Process Mining PhD Dissertation Award 2022 during the Fourth International Conference on Process Mining (ICPM 2022) for her thesis entitled "Process Instance Clustering based on Conformance Checking Artefacts".
Portraits de chercheurs : Evelyne Contejean
Un article sur Evelyne Contejean vient de paraitre dans la rubrique Portraits de chercheurs des Actualités de l'Université Paris-Saclay.
PhD Defence: Gabriel Hondet
Expressing Predicate Subtyping in Computational Logical Frameworks
by Gabriel Hondet
Tuesday 27 September 2022 at 5pm
ENS Paris-Saclay, Room 1Z14
Abstract: Safe programming as well as most proof systems rely on typing. The more a type system is expressive, the more these types can be used to encode invariants which are therefore verified mechanically through type checking procedures. Predicate subtyping extends simple type theory by allowing terms to be defined by predicates. A predicate subtype { x : A | P(x) } is inhabited by terms t of type A for which P(t) holds. This extension provides a rich and intuitive but undecidable type system.
Prix Doctorants STIC du plateau de Saclay pour Pierre Vandenhove
Pierre Vandenhove est lauréat d'un accessit au Prix « Doctorants » du plateau de Saclay dans la domaine STIC - Sciences et Technologies de l'Information et la Communication.
Nouveau livre : Informatique MPI
Fin août 2022, vient de sortir un nouveau livre par Thibaut Balabonski, Sylvain Conchon, Jean-Christophe Filliâtre, Kim Nguyễn, Laurent Sartre.
Il s'intitule "Informatique - MPI2/MPI - CPGE 1re et 2e années: Cours et exercices corrigés" et vise les enseignants d'informatique et les élèves des nouvelles classes préparatoires MP2I et MPI. En voici la table des matières.
En plus de son poids, il faut souligner le site lié qui fournit tous les codes et données du livre.
LICS Test-of-Time Award pour Philippe Schnoebelen
Philippe Schnoebelen reçoit le LICS Test-of-Time Award 2022 pour l'article Temporal Logic with Forgettable Past cosigné avec François Laroussinie (Université Paris-Cité) et Nicolas Markey (IRISA, CNRS). Au moment de la rédaction de l'article en 2002, les trois auteurs étaient membres du même laboratoire LSV qui a intégré le LMF en 2021.
La conférence LICS — Logic in Computer Science est le plus prestigieux forum annuel sur des sujets théoriques et pratiques en informatique liés à la logique au sens large. Le prix LICS Test-of-Time Award récompense un petit nombre d'articles tirés des actes du LICS des 20 dernières années (c'est-à-dire que l'article en question date du LICS 2002 et a été pris en considération cette année) qui ont le mieux résisté à "l'épreuve du temps”. En sélectionnant ces articles, le comité d'attribution tient compte de l'influence qu'ils ont eue depuis leur publication ; en raison de la nature fondamentale des travaux de la LICS, l'impact n'est souvent pas ressenti immédiatement, d'où la perspective de 20 ans.