MODEL-THEORETIC ANALYSIS OF KNOWLEDGE: PRELIMINARY REPORT.

A general semantic model of knowledge is introduced, to allow reasoning about statements such as 'He knows that I know whether or not she knows whether or not it is raining. ' This approach more naturally models a state of knowledge than previous proposals (including Kripke structures). Using this notion of model, a model theory for knowledge is developed. This theory enables one to interpret such notions as a 'finite amount of information' and 'common knowledge' in different contexts.