A note on knowledge-based programs and specifications

Knowledge-based program are programs with explicit tests for knowledge. The y have been used successfully in a number of applications. Sanders has poin ted out what seem to be a counterintuitive property of knowledge-based prog rams. Roughly speaking, they do not satisfy a certain monotonicity property , while standard programs (ones without tests for knowledge) do. It is show n that there are two ways of defining the monotonicity property, which agre e for standard programs. Knowledge-based programs satisfy the first, but do not satisfy the second. It is further argued by example that the fact that they do not satisfy the second is actually a feature, not a problem. Moreo ver, once we allow the more general class of knowledge-based specifications , standard programs do not satisfy the monotonicity property either.