- From: Lopatenko Andrei (A) <andrei.lopatenko@unibz.it>
- Date: Tue, 7 Oct 2003 14:32:02 +0200
- To: "Raphael Volz" <rvo@aifb.uni-karlsruhe.de>, "Franconi Enrico (P)" <franconi@inf.unibz.it>
- Cc: <www-rdf-logic@w3.org>, "Raphael Volz" <volz@aifb.uni-karlsruhe.de>
> > > One example is existential quantification, which you can > > only do in one directions of implication, since existentials > > in the head are generally unavailable in Datalog. Another > > example is negation, which has different semantics (incompatible > > with FOL negation). Existential quantifications are generally unavailable in Datalog but it does not mean that one can not answer some class of queries (conjunctive, for example) using datalog program. The rewriting method can be applied in this domain to get datalog program answering CQ over ontologies with existential variables in the right. > EXPTIME-hard. So, again, I don't understand what are you really doing. >
Received on Tuesday, 7 October 2003 08:35:43 UTC