Formal Modelling and Verification of Cooperative Ant Behaviour in Event-B

Multi-agent technology is a promising approach to development of complex decentralised systems that dynamically adapt to changing environmental conditions. The main challenge while designing such multi-agent systems is to ensure that reachability of the system-level goals emerges through collaboration of autonomous agents despite changing operating conditions. In this paper, we present a case study in formal modelling and verification of a colony of foraging ants. We formalise the behaviour of cooperative ants in Event-B and verify by proofs that the desired system-level properties become achievable via agent collaboration. The applied refinement-based approach weaves proof-based verification into the formal development. It allows us to rigorously define constraints on the environment and the ant behaviour at different abstraction levels and systematically explore the relationships between system-level goals, environment and autonomous ants. We believe that the proposed approach helps to structure complex system requirements, facilitates formal analysis of various system interdependencies, and supports formalisation of intricate mechanisms of agent collaboration.