Section: Overall Objectives

Introduction

VeriDis was created in January 2010 as a local team of INRIA Nancy Grand-Est. The scientific proposal includes members of the MOSEL group of LORIA, the computer science laboratory in Nancy and members of the Automation of Logic Research Group at Max-Planck Institut for Informatics in Saarbrücken, led by Christoph Weidenbach. This joint proposal was positively evaluated by the scientific experts nominated by INRIA, and the comité des projets of INRIA Nancy recommended in June 2011 that the team be created.

The objective of VeriDis is to exploit and further develop the advances and integration of interactive and automated theorem proving, with applications to the area of concurrent and distributed systems. The goal of our project is to assist algorithm and system designers to carry out formally proved developments, where proofs of relevant properties, as well as bugs, can be found with a high degree of automation.

Automated as well as interactive deduction techniques are already having substantial impact. In particular, they have been successfully applied to the verification and analysis of sequential programs, often in combination with static analysis and software model checking. Ideally, systems and their properties would be specified in high-level, expressive languages, errors in specifications would be discovered automatically, and finally, full verification could also be performed completely automatically. Due to the inherent complexity of the problem this cannot be achieved in general. However, we have observed important advances in automated and interactive theorem proving in recent years. We are particularly interested in the integration of different deduction techniques and tools, including the combination of relevant theories such as arithmetic in automated theorem proving. These advances suggest that a substantially higher degree of automation can be achieved in system verification over what is available in today's verification tools.

VeriDis proposes to exploit and further develop automation in system verification, and to apply its techniques within the context of concurrent and distributed algorithms, which are by now ubiquitous and whose verification is a big challenge. Concurrency problems are central to the development and verification of programs for multi- and many-core architectures, and distributed computation underlies the paradigms of grid and cloud computing. Typical application problems that we address include the verification of algorithms and protocols for peer-to-peer and overlay networks, such as distributed hash tables, multicast trees or gossip-based protocols. The added resilience to component failures gained by distributed computation is one of the motivations for its adoption, and constitutes another challenge for verification. We aim to move current research in this area on to a new level of productivity and quality. To give a concrete example: today a network protocol engineer designing a new distributed protocol may validate it using testing or model checking. Model checking will help finding bugs, but can only guarantee properties of a high-level model of the protocol, usually restricted to finite instances. Testing distributed systems and protocols is notoriously difficult because corner cases are hard to establish and reproduce. Also, many testing techniques require implementation, which is expensive and time-consuming, and errors are found only when they can no longer be fixed cheaply. The techniques that we develop aim at automatically proving significant properties of the protocol already at the design phase. Our methods will be applicable to designs and algorithms that are typical for components of operating systems, distributed services, and down to the (mobile) network systems industry.