Knowledge Update for Multi-Agent Syestem based on Modal Default Logic

Based on modal default logic, a multi-agent system has been built. Some concepts such as new knowledge and knowledge conflict are defined for the modal default theory Delta_i = D_i, W_i). In a multi-agent system based on the modal default logic, the knowledge of an agent can be shared with others. The aim of this paper is focused on the properties and acquisition of the extension in the modal default theory when its background set W_i) is changing. The related theorems about the extension have been proved. Furthermore, dynamic characteristics about the knowledge update for multi-agent system are being built to describe its non-monotonicity