- From: Sandro Hawke <sandro@w3.org>
- Date: Mon, 21 Jul 2003 17:35:44 -0400
- To: pat hayes <phayes@ihmc.us>
- cc: www-tag@w3.org
[3rd branch of original message] > No, look. Interoperability does NOT require that we pick a single > fixed semantics. All it requires is that your semantics for the URI > and my semantics for it are *compatible*. I don't understand well enough how to talk about the semantics of URIs to argue this point. Mostly I was trying to say the same thing you said wonderfully last week [3]: Semantics is centrally relevant to the Web, because the entire point of the Web is to convey representations from place to place, and it is only semantics which makes a representation distinguishable from random noise. Of course in general, MIME/Content types address the basic problem here. Bytestrings are always transmitted on the web (and usually in SMTP) as MIME Entities, and MIME Entities always start with a header which includes a string (the "Content-Type") which maps, via a central registry, to a specification of the intended language of the body bytestring. This is simple, obvious engineering, like using ISO country/language codes to indicate whether a given string ("chat") is meant to be understood in French or English. The technical question which is slowly coming to a boil is: How To Make Modular/Composible Languages? The design of a standard web page language is too big for one committee, so how can we break it into HTML + MathML + SMIL + SVG + whatever...? And it gets far, far worse if we want to include markup for parts inventories, business hours, delivery policies, and all the other domain knowledge people want to share on the web. It's too big for one committee, but we just make it "user defined" there will be no interoperability between user communities. XML namespaces are a baby-step [4] toward addressing this problem in XML, giving some degree of independence between module (markup language) creators, but still not even providing hooks for allowing arbitrary combinations of language modules to have well defined semantics. Others have said "if you want to mix namespaces in XML, write in RDF/XML" which comes a lot closer to an answer. But it still hasn't reached the answer if RDF without semantic extensions and RDF with semantic extensions are tranmitted with the same MIME type, has it? OWL is a semantic extension of RDF, right? If it's transmitted with the same MIME type as plain RDF, the reader wont be able to tell whether the writer intended the OWL semantics or not. TimBL says if they used terms from the OWL namespace, they are using the OWL semantics; they committed to the OWL entailment of whatever they said. But you say otherwise, I think. Unfortunately, in saying otherwise, I think you're saying we don't have language modularity in RDF/XML either. Which is bad..... -- sandro [3] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0160.html [4] I'll refrain from linking to home movies of one of my kids just learning to walk; it's cute for a baby....
Received on Monday, 21 July 2003 17:35:47 UTC