Twenty-five years of Mokum: For 25 years of data and knowledge engineering: Correctness by design in relation to MDE1 and correct protocols in cyberspace

The use of the Mokum system for correctly designing Information Systems (in the old days called Data Base Systems) and how these designs can automatically be translated into implementations, is one theme of this paper. Theoretical considerations will not be avoided. Similarities and differences with tools from the field of Model Driven Architecture, such as UML, will be demonstrated. How to deal with Mokum in a situation with many sites, as in real Cyberspace is demonstrated as a second theme. Special attention is given to a protocol: MAP, which guarantees that a certain access constraint is being maintained. The constraint being that for an object in one site to obtain access to an attribute of an object in another, a third site must give permission. The technique is based on a new notion: the Triple,2 to be used in a Knowledge based Engineering environment.