**EMCSR 2002**

*In this article, we make a proposal for a general definition of a Multiagent System, whatever may be the agents. We show how the B method can be used to give this definition a formal aspect, and we introduce a few proofs that can be performed. Finally, we introduce the notion of refinement and its advantages in the context of the formal specification of multiagent systems.
*
**SCI 2002**

*This paper presents a multi-agent system for solving one of the graph colouring problems. It differs from others, agents or not, models in the way that our main goal is to optimize the existing colouring of a graph. First, we recall the graph colouring problem and then we present a multi-agent approach. We end with the presentation of the automaton formalism of agents, and an application of this method.
*
**AIMSA 2002**

*Developing multi-agent systems may be a rather difficult task.
Having confidence in the result is still more difficult. In
this article, we describe a methodology that helps in this
task. This methodology is dedicated to global optimization
problems that can be solved combining local constraints. We
developed CASE tools to support this methodology which are
also presented. Finally, we show how this methodology has
been successfully used to develop a multi-agent system for the
graph colouring problem.
*
**JFIADSMA 2002**