- From: R.V.Guha <guha@guha.com>
- Date: Mon, 12 Aug 2002 10:15:41 -0700
- To: www-rdf-logic@w3.org
- CC: Ian Horrocks <horrocks@cs.man.ac.uk>
Ian, thank for posting these to rdf-logic. It would be good to have a discussion on the issue of different approaches to providing a semantics for the languages of the semantic web. I agree with you that for the purpose of providing a semantics for any one particular language, a "native" model theory, i.e., one that maps sets of expressions in that language to satisfying interpretations, is best in terms of perspicuity and pedagogy. So, I agree that it is important that RDF, OWL, ... be given native model theories. I would however argue that in the context of the Semantic Web, we are dealing with a situation that is quite different from when we are developing a single, standalone language. We are developing a set of languages, that are supposed to work together, i.e., wffs on the SW may include constructs from multiple of these languages. More so, these languages are expected to be layered on top of each other. Now, one can argue, as some have, that this charter is ill-concieved, but for the purpose of this email, I will assume that as a given. Further, I am also not going to get into a discussion of whether RDF/OWL should include certain features. That is the topic of another email. The problem, in this context, with relying solely on model theories, is that this does not give us a tool for providing a semantics for expressions that mix constructs from different languages. That is a rather severe limitation of relying solely on model theories. Axiomatic approaches on the other hand, by mapping everything into a common language, do enable us to provide a semantics for such "mixed expressions". I am not advocating that we abandon model theoretic approaches in favour of the other approach. I would like to see both. Which of course brings us to the issue of making sure that both are saying the same thing. Fortunately, since the whole semantics game grounds out in interpretations, I believe we can have a formal model of what it means for these two approaches to say the same thing. Pat Hayes and I have taken a stab at this in our Lbase document. I look forward to your reactions. thank you Guha
Received on Monday, 12 August 2002 13:17:25 UTC