Establishing Trusty Mutual-Belief among Cooperative Agents

Believing mutually is one important premise to ensure that cooperation among multiple agents goes smoothly. However, mutual belief among agents is always considered for granted. In this paper, we adapt a method based on the position-exchange principle (PEP) to reason about mutual belief among agents before cooperation starts. By reasoning about mutual belief among agents, we can judge whether cooperation among agents can go on rationally or not. On the other hand, if there are malicious agents involved in cooperation, even though agents believe mutually while cooperating, the profit of honesty agents will be injured. Especially in the e-commerce environment, it is crucial to establish a fair exchanging circumstance over the Internet, in which malicious agents should be forbidden from transactions. To establish trusty mutual-belief and make cooperation useful, agents should be able to reason about cheating behaviours of malicious agents during cooperation. In this paper, we put forward a process algebra approach by extending the standard pi-calculus to model cooperation plans and agents. For an agent, we define a new kind of pro-activity, expectations, to describe what action the agent expect to occur and how much the agent is satisfied with the action’s occurrence. By extending the standard pi-calculus, we can specify the expectations of agents and reason about the satisfaction degrees of agents during the their evolutions. To reason about mutual belief formally, we bind the position-exchange principle into the inference rules defined on process expressions; whereas to reason about cheating behaviours among agents during cooperation, we define a group of criteria for anti-cheating. In this paper, we also give some examples to show how agents can be formally defined in the process algebra, how agents build mutual-belief by using the PEP inference rules, and how agents reason about cheating by referring to their anti-cheating criteria during commercial transactions.