What is a (non-constructive) non-monotone logical system?
Standard logical systems enjoy the properties of reflexivity, idempotence, monotony. The latter property has been dropped in artificial intelligence systems devoted to model drawing tentative conclusions. Up to now, all attempts to characterizing these so-called non-monotone systems are unsatisfactory because these attempts either take absence of monotony as their major characteristics or give a collection of properties that also tolerate monotone systems. In contrast, we introduce in the context of non-constructive logics a characterization that indeed furnishes necessary and sufficient conditions for a system to be non-monotone. (C) 2000 Elsevier Science B.V. All rights reserved.
logic