A note on the limitations of utilizing modal logic for federated information systems

Abstract

Recently much effort has been put into using modal logic representation lan­ guages for different kinds of distributed database and distributed problem solving systems. We have ourselves presented an architecture realizing a Federated lnformation System (FIS) for a set of semi-autonomous axiomatic modal propositional logics. We have elsewhere shown modal logic to be ade­ quate for static FISs, but for dynamic situations each node must be augmented by an ordering relation at the very least to admit descriptions of realistic situations such as a node joining or leaving an FIS, and for quantifying node credibility representing the quality of sorne given imported information. These requirements are more easily met_ using the language inflationary Data log than by using modal operators. A motivation for this paper is given, followed by an investigation of the most common ways of utilizing axiomatic modal logic in the field of database theory today. Limitations are identified and discussed, and finally first­ order logic with finite structures is briefly surveyed.