Some Things That Hashless HTTP URIs Can Name

Editor's Working Draft 1 April 2005 $Revision: 1.7 $

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Dan Brickley, W3C


This document has no standing at all. I'm experimenting with drafting of a document that provides a VM TF perspective on the SWBP/TAG interaction regarding RDF/OWL class and property names. If it works, I'll write a proper abstract. In particular be aware that although this document has the draft form of a W3C Working Draft, no decision has been taken by the WG to publish any such document as a formal WD. --Dan

Status of This Document

This document is a by-product of the Vocabulary Management Task Force of the Semantic Web Best Practices and Deployment Working Group. It is not a formal W3C publication and has received no review from the Task Force or WG at this stage. This work is part of the Semantic Web Activity in the W3C Technology & Society Domain.

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

Table of Contents

  1. Introduction
  2. Example Resources
  3. Conclusions

1. Introduction

This document addresses some aspects of the What do HTTP URIs Identify? question. In doing so, it touches upon the TAG issue known as httpRange-14. Readers of (this version of) this document will need some familiarity with those debates. The HashVsSlash entry in the ESW wiki offers some more background discussion.

This document does not attempt to articulate a complete account of the things that can be named with #-less HTTP URIs (henceforth HLHUs, for 'hashless HTTP URI's). Instead, it offers a purely positive account of Some Things That Hashless HTTP URIs Can Name, drawing attention to both their diversity and to some of their common characteristics. It offers no opinion regarding the characteristics of things that cannot (per the appropriate specfications) be named with HLHUs. Readers should however be aware that the selection of HLHU-namable things presented in this document is controversial. Specifically, the assertion that RDF (RDFS and OWL) classes and properties are HLHU-namable is a matter of some ongoing controversy in the Semantic Web community, and is the topic of a dialog between the SW Best Practices WG and the TAG.

The structure of this document is simple. It begins with some general observations about URIs, and in particular HTTP URIs. It presents a short but illustrative list of some of the many kinds of thing that (it is asserted) can be named with HLHUs, and then draws some tentative conclusions.

URIs, HTTP URIs, and hashless HTTP URIs

Machine-processable unique identifiers play a central role in the architecture of the World Wide Web. See Architecture of the World Wide Web, Volume One (W3C Recommendation 15 December 2004) for detailed discussion.

In the general case, URIs identify "resources" (a term roughly analagous to "thing). Any particular URI identifies at most one resource, ie. at most one thing. Some URI schemes can identify various kinds of non-information resources, such as physical artifacts, mathematical abstractions etc. Our present concern is not with URIs in the general case, but with URIs in the 'http:' scheme. There is also a view (@@is this articulated in webarch?) that the use of the "#" fragment/view URI allows identifiers in a scheme to "step outside" the referential limitations specific URI schemes, ie. xyz://foo#bar is read as identifying "the thing called 'bar' in 'xyz://foo'", regardless of the range of things the xyz: URI scheme properly identifies. The concern in this document is with presenting (and analysing) a list of things that can be named with HTTP URIs, without relying on the #-mechanism.

The WebArch recommendation introduces the notion of "information resources".

The distinguishing characteristic of these resources is that all of their essential characteristics can be conveyed in a message.

2. Example Resources

Initial list taken from What do HTTP URIs Identify? by TimBL.

3. Conclusions