Logical systems for reasoning about multi-agent belief, information acquisition and trust

In this paper, we consider the influence of trust on the assimilation of acquired information into an agent's belief. By use of modal logic tools, we characterize the relationship among belief, information acquisition and trust both semantically and axiomatically. The belief and information acquisition are respectively represented by KD45 and KD normal modal operators, whereas trust is expressed by a modal operator with minimal semantics. One characteristic axiom of the basic system is if agent i believes that agent j has told him the truth of p and he trusts the judgement of j on p, then he will also believe p. In addition to the basic system, some variants and further axioms for trust and information acquisition are also presented to show the expressive richness of the logic.