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LC Comments, 2.2-2.3

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Fri, 5 Mar 2004 23:19:32 +0100
Message-Id: <2D745FFC-6EF3-11D8-BF98-0003939E0B44@isr.umd.edu>
To: public-webarch-comments@w3.org

I don't see how to usefully split the discussion of this section, as 
the first line of 2.2 refers to 2.3.

"""The requirement for URIs to be unambiguous demands that different 
agents do not assign the same URI to different resources."""

But it's ok that the same agent does so? Sorry if that sounds snarky, 
but it is a genuine question. I would have thought that the primary 
case was the resource owner...thus far, in the document, no one else 
seems to have the power to *assign* the same URI to different 
resources. E.g., principle: URI Assignment, the first line of 2.1, Good 
Practice: URI aliases.

(Hmm. In 2.1, right after Good Practice: URI Aliases, we get the notion 
of URI Producers. Who are they? Frankly, I don't find the arbitrary 
shifting of terms of art in a technical document to be helpful. None of 
these terms are defined in the glossary, either. Perhaps this isn't a 
technical document? If so, I'm going to feel a bit sheepish reading it 
this closely. Section 1.1.1 suggests that it is meant to be a guide for 
technical people like me (I do all of 1-4). Hmm. Section 1.1.2 says: 
"""This document strikes a balance between brevity and precision while 
including illustrative examples.""" Ok, that gives me some standard. I 
think the above claim  doesn't strike the right balance between brevity 
and precision.)

There's another reading, to wit, that the *URI* can be unambiguous 
(say, because ambiguity of a URI is defined to be having being assigned 
to more than one resource, and assignment can literally only be done by 
the URI owner, and the URI *can* successfully only assign it to one 
resource (none of these are obvious!)) while various agents can *use* 
it ambiguously. On this reading, the requirment of URI ambiguity does 
*not* demand that different agents do not *use* the same URI to refer 
to different resources. (I don't know if you mean "assign" up there in 
the restricted sense I was using in the definition of ambiguity, or 
just to mean "refer", or something else.)

Section 2.3 says that the ambiguous *use* of URIs is to be avoided 
(though, I'll point out, that the Good Practice is ambiguous between 
ambiguous URIs and ambiguous *use* of URIs).

Of course, certain ambiguity doesn't matter, e.g., replicating Quine, I 
might use a URI to refer to me, the human being, and someone else to 
refer to the collection of undetatched people parts. As long as all our 
uses *align* in (all) our interactions, we're fine, ambiguous 
assignment or not.

Sorry for the quick digression into philosophy of languages, but, 
really, at this time of night, I feel a little justified in turn around 

"""Hierarchical delegation of authority. This approach, exemplified by 
the "http" and "mailto" schemes, allows the assignment of a part of URI 
space to one party, reassignment of a piece of that space to another, 
and so forth."""

First use of 'URI space', which is undefined. I see 'information 
space', 'uniform address space', and, of course, 'namespace'. As far as 
I can tell, only 'namespace' has a definition (and it's not in this 
doc, which is fine). Perhaps this is only editorial. A URI space seems 
clear (a set of URIs? why not say that then?), but I did spend some 
time wondering if it was the same as an infromation space or address 
space. *Are* you using unambiguous phrases here? Are they aliases? Is 
there a problem with either defining terms or using only one where 
there's only one concept? Some principles of the web apply well to 
technical prose.

"""Whatever the techniques used, except for the checksum case, the 
agent has a unique relationship with the URI, called URI ownership. """

Here is what I can find on what's an "agent", prior to this passage:
	""" Within each of these systems, agents (people and software) """
	"""strate typical behavior of Web agents  people or software (on 
behalf of a person, entity, or process) acting on this information 
space. Software agents include servers, proxies, spiders, browsers, and 
multimedia players.""""

So, an agent is a person or a program. Thus, every http uri has, 
supposedly, one, and only one, person or program that is its owner. 
However, institutional ownership seems possible, as is joint ownership.

"""The social implications of URI ownership are not discussed here. 
However, the success or failure of these different approaches depends 
on the extent to which there is consensus in the Internet community on 
abiding by the defining specifications. """"

First you say that the social implications of URI ownership are *not* 
discussed here, then go on to discuss some social implications. Don't 
do that.

I don't believe the second statement of that quote, at least on many 
interpretations, and I've objected to its use in various technical 
arguments, some with TAG members. If this passage is to be a stick to 
beat me with in technical debate in W3C working groups, then I 
strenuously object to it, especially without substantial explication 
and clarification. So, I make the strong comment that I want this line 
struck. I object to it.

Is anything in this document normative? I notice that there is some 
rejection of adding a conformance section, which is fine, but I have 
*NO* idea how to use this document in working groups, nor do I know how 
it may be used by others. I totally fail to see how this can be 
helpful. So, I would like some guidance about that.

Bijan Parsia.
Received on Friday, 5 March 2004 17:19:29 UTC

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