Section: Partnerships and Cooperations
European Initiatives
FP7 & H2020 Projects
Proofcert

There is little hope that the world will know secure software if we cannot make greater strides in the practice of formal methods: hardware and software devices with errors are routinely turned against their users. The ProofCert proposal aims at building a foundation that will allow a broad spectrum of formal methods—ranging from automatic model checkers to interactive theorem provers—to work together to establish formal properties of computer systems. This project starts with a wonderful gift to us from decades of work by logicians and proof theorist: their efforts on logic and proof has given us a universally accepted means of communicating proofs between people and computer systems. Logic can be used to state desirable security and correctness properties of software and hardware systems and proofs are uncontroversial evidence that statements are, in fact, true. The current stateoftheart of formal methods used in academics and industry shows, however, that the notion of logic and proof is severely fractured: there is little or no communication between any two such systems. Thus any efforts on computer system correctness is needlessly repeated many time in the many different systems: sometimes this work is even redone when a given prover is upgraded. In ProofCert, we will build on the bedrock of decades of research into logic and proof theory the notion of proof certificates. Such certificates will allow for a complete reshaping of the way that formal methods are employed. Given the infrastructure and tools envisioned in this proposal, the world of formal methods will become as dynamic and responsive as the world of computer viruses and hackers has become.
Collaborations in European Programs, Except FP7 & H2020
FISP: ANR blanc International
Participants : Kaustuv Chaudhuri, François Lamarche, Sonia Marin, Dale Miller, Lutz Straßburger.
The FISP project is part of a longterm, ambitious project whose objective is to apply the powerful and promising techniques from structural proof theory to central problems in computer science for which they have not been used before, especially the understanding of the computational content of proofs, the extraction of programs from proofs and the logical control of refined computational operations. So far, the work done in the area of computational interpretations of logical systems is mainly based on the seminal work of Gentzen, who in the midthirties introduced the sequent calculus and natural deduction, along with the cutelimination procedure. But that approach shows its limits when it comes to computational interpretations of classical logic or the modelling of parallel computing. The aim of our project, based on the complementary skills of the teams, is to overcome these limits. For instance, deep inference provides new properties, namely full symmetry and atomicity, which were not available until recently and opened new possibilities at the computing level, in the era of parallel and distributed computing.
COCA HOLA: ANR JCJC Project
Participant : Beniamino Accattoli.

Title: COst model for Complexity Analyses of HigherOrder programming LAnguages.

Collaborators: Ugo Dal Lago (University of Bologna & Inria), Delia Kesner (Paris Diderot University), Damiano Mazza (CNRS & Paris 13 University), Claudio Sacerdoti Coen (University of Bologna).
The COCA HOLA project aims at developing complexity analyses of higherorder computations, i.e. that approach to computation where the inputs and outputs of a program are not simply numbers, strings, or compound datatypes, but programs themselves. The focus is not on analysing fixed programs, but whole programming languages. The aim is the identification of adequate units of measurement for time and space, i.e. what are called reasonable cost models. The problem is nontrivial because the evaluation of higherorder languages is defined abstractly, via highlevel operations, leaving the implementation unspecified. Concretely, the project will analyse different implementation schemes, measuring precisely their computational complexity with respect to the number of highlevel operations, and eventually develop more efficient new ones. The goal is to obtain a complexityaware theory of implementations of higherorder languages with both theoretical and practical downfalls.
The projects stems from recent advances on the theory of time cost models for the lambdacalculus, the computational model behind the higherorder approach, obtained by the principal investigator and his collaborators (who are included in the project).
COCA HOLA will span over three years and is organised around three work packages, essentially: