Automated support for external consistency

Two models are presented of how to achieve an external-consistency objective motivated by the enterprise integrity of D.D. Clark and D.R. Wilson. The authors´ notion of external consistency deals with the correctness of both assertions-propositions claimed to be true by their source-and requests-commands, authorizations, and similar sentences intended to change their source´s environment. Each model considers assertions and requests from the perspective of both users and the automated system; this gives rise to defined responsibilities and requirements for both. The first, simple model assumes that users can reliably provide correct inputs to the automated system. The second model, taking a more realistic view of human enterprises, assumed that only experienced users have such capabilities. In both cases, the primary requirement imposed on the automated system is that it produces correct outputs provided enough of its inputs are correct. The authors call this an `output warranty´ requirement in reference to the vendor´s responsibility for the quality of the automated system