From: Peter F. Patel-Schneider (pfps@research.bell-labs.com)
Date: 02/12/04
From: Sandro Hawke <sandro@w3.org> Subject: Re: reifying variables Date: Thu, 12 Feb 2004 09:48:30 -0500 > > From: Sandro Hawke <sandro@w3.org> > > Subject: Re: reifying variables > > Date: Thu, 12 Feb 2004 08:08:30 -0500 > > > > > > > > > > So SWRL makes no claim to get it right, which is okay, but of course > > > > > this means it's not really an "RDF Concrete Syntax", it's an "RDF-Like > > > > > Concrete Syntax." Not so good. > > > > > > > > Well, this is probably the best that can be done. > > > > > > In what way is it better to use an "RDF-Like" syntax? That seems to > > > me like the worst of both world -- all the syntactic beauty and > > > convenience elegance of RDF/XML, plus all the standard-ness of the > > > <blink> tag. > > > > > > -- sandro > > > > Technically I don't see any reason to use an RDF syntax whatsoever. > > However, using RDF syntax has appeared to be the price to enter the > > Semantic Web arena. > > I understand Jim Hendler made it the price of admission to the DAML > program, when he was Program Manager. Beyond that, I'm not sure. I > think the W3C gives mixed signals, sometimes using n3 instead. I argued long and loud in the W3C WebOnt working group about problems that using the RDF syntax caused. This argument didn't go anywhere, so I gave in and created a partial solution for OWL. (Academically this was a great success, as I was able to get some research papers out of my involvement with the working group, but I'm not so sure whether this was a practical success.) > I've > sometimes campaigned unsuccessfully for a standard meta-language, in > which the syntax and semantics of practical data languages are > described. XML might be the syntax half of this. Isn't model theory (or even mathematics) the semantics half? :-) > In any case, using an "RDF-Like" syntax is using counterfeit money and > I suspect is only accepted as the price of admission by mistake. I > apologize for not noticing and commenting on SWRL doing this back in > November. There have been several proposals to make this sort of solution the official one, including things like dark triples. I don't like the RDF syntax, and don't believe that uninterpreted triples are a good solution to the problem. I would very much welcome a statement from W3C that Semantic Web languages do not have to be written in triples (or quads, or quints, ..., as in several recent proposals). > > I would be much, much happier if the Semantic Web had multiple syntaxes. I > > have argued this in the past, to no avail, and have even written papers > > proposing multiple-syntax versions of the Semantic Web. I don't see any > > technical reasons to not go to a multiple-syntax version of the Semantic > > Web. > > You would agree there's a cost to each new language, right? No. I do not believe that there is a net cost for most new languages/representations. New languages/representations are accepted in part because of problems with existing languages/representations. If the new language/representation does not have benefits outweighing its costs, it is unlikely to be accepted. > Having > hundreds of languages isn't practical (unless some meta-language > approach is used, but then there aren't really hundreds of languages). Well, what using XML, and having multiple Schemas/DTDs for the different semantic languages? This certainly cuts the cost of parsers! > I've occasionally heard the observation that markets can generally > support two standards. In this case, RDF/XML sets a pretty low bar > for the competition. I think the RDF model itself is a pretty high > bar, but time will tell. > > -- sandro Well, the Web has quite a number of languages/representations, even if you only count the major ones. A partial list is XHTML CSS PNG XLink RDF/XML XVF SMIL (the above are from the Web Architecture document) JPEG GIF PDF PS DOC (EXCEL) Some of these are XML dialects but some are not. Current web browsers can handle lots of different languages/representations, and can be configured to get outside help to handle others. peter
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