Reasoning about dynamics of trust and agent beliefs

Many formal frameworks have been proposed for specifying and reasoning about the notion of trust and trust mechanisms in agent-based systems. Typed Modal Logic (TML) is a logic of beliefs which is suitable for for the description of, and reasoning about, trust for multi-agent systems by formalising trust policies of the system and agent metabeliefs in its security mechanisms. In this paper, by adopting the methodology of Finger and Gabbay for temporalising a logic system, we combine TML with a temporal logic, so that the users can also model evolving theories of trust. In the resulting logic, denoted by TML+, temporal properties of trust and agent beliefs can be expressed in a natural way by combinations of temporal and modal belief operators.