Section: Partnerships and Cooperations
European Initiatives
FISP: ANR blanc International
Participants : Kaustuv Chaudhuri, François Lamarche, Sonia Marin, Dale Miller, Lutz Straßburger.
The FISP project is part of an ambitious, longterm 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: