- From: Sampo Syreeni <decoy@iki.fi>
- Date: Wed, 30 Jul 2008 03:57:06 +0300 (EEST)
- To: Bijan Parsia <bparsia@cs.man.ac.uk>
- cc: Richard Cyganiak <richard@cyganiak.de>, Semantic Web <semantic-web@w3.org>
On 2008-07-30, Bijan Parsia wrote: > For many reasons. I.e., I would recommend this even if subpropertying > rdfs:label becomes legit OWL DL. I already know that you're one of the few people who're intimate with the logical details, so... Could you recap, after such an extensive discussion, *why* subproperties of rdfs:label (or any other property for that matter) aren't compatible with OWL DL? >From what I can understand, either the relevant portion of the combined grammar will not be utilized in inference/rewriting, or it will and the results will agree higher up the ladder. The cinch would then be that there's something very special about the computational realization of RDFS semantics which would kill the nice termination properties of the inferencing process at the OWL DL level. If I'm right, what is it that causes said problem? Or if I'm wrong, could you elaborate? > """(rdfs:comment, rdfs:seeAlso, rdfs:isDefinedBy and rdfs:label are > included here because some constraints which apply to their use can be > stated using rdfs:domain, rdfs:range and rdfs:subPropertyOf. Other > than this, the formal semantics does not assign them any particular > meanings.)""" They don't possess *formal* semantics, other than those assigned to them via application of rdfs:subPropertyOf and so on. So the pure formalists amongst the RDF/RDFS/OWL/DAML/whatever crowd would say *just* that. That still doesn't mean said primitives possess *no* semantics at *all*. Their *formal* semantics are restricted to whatever derivative, inferential assertions they give rise to in combination with the rest of the asserted theory, to be sure. But they *do* still have their separate, hazy, intuitive, linguistic, common sense meanings/semantics. The latter are also why they were included in the specification(s) in the first place: as a bootstrap that enables us to bridge the gap between the everyday meaning needed for actual application development (e.g. "me" in the human sense as opposed to the unique identifier "oid:1.3.6.1.4.1.12798.1.2049"), and the nitty-gritty of formal logic (e.g. me hasLittleBrother myLittleBrother). That bridge is quite obviously needed for any proper application of the technology, no matter how consistent, logical and machine processable it is down below. I would also argue that that's why Tim would, in my mind, so much like to subclass rdfs:label for every kind of name: ideally a human software developer would like every kind of human readable label/name to present itself automatically to him. And what then is a human readable name/label but a subtype of the original, purposely included, singular RDF label "rdfs:label"? That what it was *meant* for, and the same goes for the rest of the "hazy" stuff like comments... The real world denotations of those formal URI's are meant to document and distinquish certain central, useful, human intuitions about the concepts the RDF family of languages formally reasons upon. If we, for some formal reason, cannot subtype them, we'd be losing the logical unity of the framework, at least at the human readable level. I mean, two different kinds of labels/names? In the same language? What if some idiot declared both? What would I call my concept *then*?!? >> 4. OWL people ask RDF people to stop subclassing these properties in >> order to meet the restrictions imposed by OWL-DL. > > Do whatever you want. That is not a very constructive answer, in my mind. I'd rather see a consensus on what the problem is, and then a clean, mutually agreeable solution which adapts one -- or more likely both -- of the standards so that these sorts of clashes just cease to be. And *especially* at such a fundamental level as OWL DL: that wasn't supposed to be the specification that gives us the most trouble within the RDF family of formal languages. It was supposed to be the easiest and most useful. Now I'm already beginning to be disappointed... -- Sampo Syreeni, aka decoy - mailto:decoy@iki.fi, tel:+358-50-5756111 student/math+cs/helsinki university, http://www.iki.fi/~decoy/front openpgp: 050985C2/025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2
Received on Wednesday, 30 July 2008 00:57:54 UTC