Reasoning About Belief, Evidence and Trust in a Multi-agent Setting

We present a logic for reasoning about the interplay between belief, evidence and trust in a multi-agent setting. We call this logic DL-BET which stands for "Dynamic Logic of Belief, Evidence and Trust". According to DL-BET, if the amount of evidence in support a given fact. and the ratio of evidence in support of phi to the total amount of evidence in support of either phi or its negation are sufficient then, as a consequence, one should be willing to believe phi. We provide a sound and complete axiomatization for the logic and illustrate its expressive power with the aid of a concrete example.