François Laroussinie

Temporal logic with forgettable past

We investigate NLTL, a linear-time temporal logic with forgettable past. NLTL can be exponentially more succinct than LTL+Past (which in turn can be more succinct than LTL). We study satisfiability and model checking for NLTL and provide optimal automata-theoretic algorithms for these EXPSPACE-complete problems.

CONCUR 2010 - Concurrency Theory

Dating Concurrent Objects: Real-Time Modeling and Schedulability Analysis.- Applications of Shellable Complexes to Distributed Computing.- Concurrency and Composition in a Stochastic World.- Taming Distributed Asynchronous Systems.- Trust in Anonymity Networks.- Learning I/O Automata.- Constrained Monotonic Abstraction: A CEGAR for Parameterized Verification.- Information Flow in Interactive Systems.- From Multi to Single Stack Automata.- A Geometric Approach to the Problem of Unique Decomposition of Processes.- A Logic for True Concurrency.- A Theory of Design-by-Contract for Distributed Multiparty Interactions.- Bisimilarity of One-Counter Processes Is PSPACE-Complete.- Nash Equilibria for Reachability Objectives in Multi-player Timed Games.- Stochastic Real-Time Games with Qualitative Timed Automata Objectives.- Session Types as Intuitionistic Linear Propositions.- Session Types for Access and Information Flow Control.- Simulation Distances.- Mean-Payoff Automaton Expressions.- Obliging Games.- Multipebble Simulations for Alternating Automata.- Parameterized Verification of Ad Hoc Networks.- Termination in Impure Concurrent Languages.- Buffered Communication Analysis in Distributed Multiparty Sessions.- Efficient Bisimilarities from Second-Order Reaction Semantics for ?-Calculus.- On the Use of Non-deterministic Automata for Presburger Arithmetic.- Reasoning about Optimistic Concurrency Using a Program Logic for History.- Theory by Process.- On the Compositionality of Round Abstraction.- A Linear Account of Session Types in the Pi Calculus.- Generic Forward and Backward Simulations II: Probabilistic Simulation.- Kleene, Rabin, and Scott Are Available.- Reversing Higher-Order Pi.- Modal Logic over Higher Dimensional Automata.- A Communication Based Model for Games of Imperfect Information.- Flat Coalgebraic Fixed Point Logics.- Conditional Automata: A Tool for Safe Removal of Negligible Events.- Representations of Petri Net Interactions.- Communicating Transactions.- Consistent Correlations for Parameterised Boolean Equation Systems with Applications in Correctness Proofs for Manipulations.

Model Checking Timed Automata with One or Two Clocks

In this paper, we study model checking of timed automata (TAs), and more precisely we aim at finding efficient model checking for subclasses of TAs. For this, we consider model checking TCTL and TCTL ≤,≥ over TAs with one clock or two clocks.

A hierarchy of temporal logics with past

We extend the classical hierarchy of branching-time temporal logics between UB and CTL* by studying which additional expressive power (if any) stems from the incorporation of past-time modalities. In addition, we propose a new temporal combinator, N for “Now”, that brings new and interesting expressive power. In several situations, non-trivial translation algorithms exist from a temporal logic with past to a pure-future fragment. These algorithms have important practical applications e.g. in the field of model-checking.

CMC: A Tool for Compositional Model-Checking of Real-Time Systems

In this paper we present a tool (CMC) for compositional model-checking of real-time systems. CMC is based on a completely different method compared to existing real-time verification tools (HYTECH, KRONOS, UPPAAL). After a description of the method, we illustrate its efficiency by considering two examples: the Fischer’s mutual exclusion protocol and a railroad crossing system.

Guidelines for a graduate curriculum on embedded software and systems

The design of embedded real-time systems requires skills from multiple specific disciplines, including, but not limited to, control, computer science, and electronics. This often involves experts from differing backgrounds, who do not recognize that they address similar, if not identical, issues from complementary angles. Design methodologies are lacking in rigor and discipline so that demonstrating correctness of an embedded design, if at all possible, is a very expensive proposition that may delay significantly the introduction of a critical product. While the economic importance of embedded systems is widely acknowledged, academia has not paid enough attention to the education of a community of high-quality embedded system designers, an obvious difficulty being the need of interdisciplinarity in a period where specialization has been the target of most education systems. This paper presents the reflections that took place in the European Network of Excellence Artist leading us to propose principles and structured contents for building curricula on embedded software and systems.

ATL with Strategy Contexts: Expressiveness and Model Checking

We study the alternating-time temporal logics ATL and ATL* extended with strategy contexts: these make agents commit to their strategies during the evaluation of formulas, contrary to plain ATL and ATL* where strategy quantifiers reset previously selected strategies. We illustrate the important expressive power of strategy contexts by proving that they make the extended logics, namely ATLsc and ATLsc*, equally expressive: any formula in ATLsc* can be translated into an equivalent, linear-size ATLsc formula. Despite the high expressiveness of these logics, we~prove that their model-checking problems remain decidable by~designing a tree-automata-based algorithm for model-checking ATLsc* on the full class of

Model checking probabilistic timed automata with one or two clocks

n

Specification in CTL + Past for verification in CTL

-player concurrent game structures.

Model Checking CTL+ and FCTL is Hard

Probabilistic timed automata are an extension of timed automata with discrete probability distributions.We consider model-checking algorithms for the subclasses of probabilistic timed automata which have one or two clocks. Firstly, we show that PCTL probabilistic model-checking problems (such as determining whether a set of target states can be reached with probability at least 0.99 regardless of how nondeterminism is resolved) are PTIME-complete for one clock probabilistic timed automata, and are EXPTIME-complete for probabilistic timed automata with two clocks. Secondly, we show that the model-checking problem for the probabilistic timed temporal logic PTCTL is EXPTIME-complete for one clock probabilistic timed automata. However, the corresponding model-checking problem for the subclass of PTCTL which does not permit both (1) punctual timing bounds, which require the occurrence of an event at an exact time point, and (2) comparisons with probability bounds other than 0 or 1, is PTIME-complete.