- From: Jonathan Borden <jonathan@openhealth.org>
- Date: Wed, 24 Jul 2002 09:40:23 -0400
- To: "Roy T. Fielding" <fielding@apache.org>
- Cc: <www-tag@w3.org>
Roy T. Fielding wrote: > > A URI is an identifier. The semantics of the resource it identifies > are defined by the sameness of representations of that resource over > time, not by any property of the identification system used to create > that identifier. In short, a URI reference has the semantics that > other people assign to it when they persist in trying to use it to > refer to something useful. Terrific. This para should (IMHO) be included in the "arch doc". BTW: I've suggested equating resources by the equality of their representation sets as axioms [10,11] in http://www.openhealth.org/RDDL/SchemaAlgebra [[ [10] equivalent(URIa,URIb) := Entities(URIa) = Entities(URIb) and cardinality(Entities(URIa)) > 0 Two URIs are equivalent when they map to the same set of entities. [11] equivalent(A,B) <=> exists URIa such that A = resource(URIa) and exists URIb such that B = resource(URIb) and equivalent(URIa,URIb) Two resources a and b are equivalent if the set of entities given the URIa and URIb are equal where URIa identifies a and URIb identifies b. ]] where Entities(URI) is the set of entities which the URI maps to across media-types, time, and other e.g. HTTP request parameters. > This isn't a property of the technology; > it is a property of how people use the technology. The same is > true of "words", whether or not you are prepared to admit it. > That is the basis of every modern human language except French. Just curious, what is the problem with French? URIs _are_ words, words that may be attached to their dictionary (e.g. "http:...", but nonetheless. > > Some identifiers are better (more persistent, more available, more > whatever-you-like) than others. http identifiers are ideal for > resources that can be accessed through HTTP via TCP/IP. Other > identifiers may be better for some cases, but only if they come > with a support infrastructure that makes them sufficiently useful > for people. People decide what identifier is best for any given > situation, and it is a fundamental principle of the Web that > any URI scheme can be used as an identifier within any context or > protocol element that requires a URI. > > XML namespaces, by the way, can be accessed through HTTP, as can > robots, climate controls, beaches, and any other thing for which > someone cares to provide a meaningful representation via HTTP. > oh yeah. Jonathan
Received on Wednesday, 24 July 2002 09:46:24 UTC