Reasoning in a Closed Terminology

The paper presents an extension of Description Logic to cope with conguration problems. In the paradigm of non structural algorithms the denitions are dierent from classic one. The study originated by Weida [3] in 1992 with CLASSIC and by others [2] (PROSE at AT&T) must be reviewed in order to take account of the extended expressiveness of the language and of its semantic. The paper describes what is intended by terminological closure, a way to modify and constrain the terminology in order to allow the special kind of reasonning needed in the framework of conguration. The implementation is presented: it is based on the introduction of special indicators that are manipulated easily, in a uniform way in the tableaux-based inference engine. Indicators are convenient because they allow to be constructed when concepts denitions are interpreted and the process can be applied on general forms of concepts denitions. The use of multi TBoxes gives a help for modelling..