- From: Wagner, G.R. <G.R.Wagner@tm.tue.nl>
- Date: Wed, 19 Sep 2001 11:43:52 +0200
- To: "'Pat Hayes'" <phayes@ai.uwf.edu>, "Wagner, G.R." <G.R.Wagner@tm.tue.nl>
- Cc: www-rdf-rules@w3.org
> I would say that the languages of queries and rules in Prolog > were *identical*: both consist of Horn clauses. Please notice that Prolog rules (as well as any other practical computational rule concept such as SQL views and OCL implications) are *not* Horn clauses! They are, for good reasons, more expressive, allowing for negation in their body/antecedent (and other things, such as quantifiers, as in the case of SQL views). We should consider the concept of a rule as a basic one that is not derived from that of a Horn clause (which happens to be a very restricted/simplified type of rule). The concept of a Horn clause is tight to classical (two-valued) logic. But rules play a role in all kinds of formalism with a non-classical logic semantics (such as intuitionistic, partial, temporal, inconsistency-tolerant logic, etc.). -Gerd -------------------------------------------- Gerd Wagner Email: G.Wagner@tm.tue.nl http://tmitwww.tm.tue.nl/staff/gwagner Eindhoven University of Technology Faculty of Technology Management Department of Information & Technology P.O. Box 513 5600 MB Eindhoven Tel: (+31 40) 247 26 17 The Netherlands Fax: (+31 40) 243 26 12
Received on Wednesday, 19 September 2001 05:44:04 UTC