Subject: What is this entry about?

From: James M Snell <[email-masked]>
Date: Fri, 21 Oct 2005 12:15:30 -0700

Ok, so thus far: we can indicate resources that are related to the given 
entry; we can indicate that an entry is a reply to another entry; we can 
specify categories to which the entry belongs; but there is currently no 
way of indicating the *subject* of the entry. 

The best options appear to be:

a. Use dc:subject (appears to be a perfectly acceptable solution to me 
assuming that the subject indication is intended for human consumption

   <entry>
     <dc:subject>The Atom Specification</dc:subject>
   </entry>

or...

b. Use link[rel="subject"] (which works if the subject is 
identified/described by a dereferenceable URI)

   <entry>
     <link rel="subject" 
href="http://www.ietf.org/internet-drafts/draft-ietf-atompub-format-11.txt" 
/>
   </entry>

I think either approach works. The dc:subject approach is ambiguous.  
The link approach requires invention.

Thoughts?

- James

---

From: Bill de hÓra <[email-masked]>
Date: Fri, 21 Oct 2005 21:59:43 +0100

> The link approach requires invention.

The link approach doesn't seem to be less ambiguous than dc:subject. For
lessened ambiguity you might want to use published subject indicators a
la topic maps.

cheers
Bill

---

From: James M Snell <[email-masked]>
Date: Fri, 21 Oct 2005 14:34:01 -0700

>lessened ambiguity you might want to use published subject indicators a
It is "less ambiguous" in that a URI is less ambiguous that some 
arbitrary text string.  Further, the link approach is perfectly 
compatible with the "published subject indicators a la topic maps" 
approach. 

- James

---

From: Bill de hÓra <[email-masked]>
Date: Fri, 21 Oct 2005 22:49:17 +0100

> compatible with the "published subject indicators a la topic maps"

There's no requirement to use an "arbitrary text string" in dc:subject*.
And even then, I have no idea how a URL (you did say these things had to
be dereferenced) is less ambiguous than a string - they're equally
arbitrary unless we're talking about their use in something like OWL.

The link approach still doesn't seem to be less ambiguous than
dc:subject, ie it does not seem to be a basis for choosing one over the
other.

cheers
Bill

* The dc:subject value is recommended to be taken from some controlled
set. The @rel=subject idea doesn't say anything about the link being a
PSI. The "link approach" is "perfectly compatable" then with PSIs
insofar as you would have some other interpretation that lookups the
URIs and sees if they're actually PSIs, or not.

---

From: "A. Pagaltzis" <[email-masked]>
Date: Sat, 22 Oct 2005 01:18:50 +0200

* James M Snell <[email-masked]> [2005-10-21 21:25]:
> Ok, so thus far: we can indicate resources that are related to
> the given entry; we can indicate that an entry is a reply to
> another entry; we can specify categories to which the entry
> belongs; but there is currently no way of indicating the
> *subject* of the entry. 
> 
> a. Use dc:subject (appears to be a perfectly acceptable
> solution to me assuming that the subject indication is intended
> for human consumption
> 
> or...
> 

Err, are you forgetting atom:category? Doesn’t that satisfy all
your wants *and* more? It has a URI, a term and a human-readable
label.

Regards,
-- 
Aristotle Pagaltzis // <http://plasmasturm.org/>

---

From: James M Snell <[email-masked]>
Date: Fri, 21 Oct 2005 16:47:44 -0700

>your wants *and* more? It has a URI, a term and a human-readable
I dunno, that's why I was asking ;-)

atom:category works well for categorizing entries, but does it really 
tell us what the entry is about?  For instance, suppose that I want to 
indicate that an entry is about http://www.ibm.com and file that in a 
category called technology?  The categorization of the entry is 
different than the subject of the entry.. tho both are definitely related.

- James

---

From: Antone Roundy <[email-masked]>
Date: Fri, 21 Oct 2005 18:03:54 -0600

On Oct 21, 2005, at 5:47 PM, James M Snell wrote:
> atom:category works well for categorizing entries, but does it  
> really tell us what the entry is about?  For instance, suppose that  
> I want to indicate that an entry is about http://www.ibm.com and  
> file that in a category called technology?  The categorization of  
> the entry is different than the subject of the entry.. tho both are  
> definitely related.

Why don't we define link/@rel="about" for pointing to a specific  
internet resource that an entry is about (a little more specific than  
the general case of rel="related").  I know we discussed this before  
and in the chaos of trying to hammer the spec out, didn't do it, but  
I still think it's a good idea.

---

From: Bill de hÓra <[email-masked]>
Date: Sat, 22 Oct 2005 13:39:16 +0100

Antone Roundy wrote:
>> tell us what the entry is about?  For instance, suppose that  I want
>> to indicate that an entry is about http://www.ibm.com and  file that
>> in a category called technology?  The categorization of  the entry is
> and in the chaos of trying to hammer the spec out, didn't do it, but  I
> still think it's a good idea.

-1 to about. The proposal here is saying the feed is subject to the link
not that the link is the object of the feed. About can mean either.

cheers
Bill

---

From: Bill de hÓra <[email-masked]>
Date: Sat, 22 Oct 2005 15:16:13 +0100

James M Snell wrote:
> tell us what the entry is about?  

This is the same as the dc v custom thing. Atom category imparts no less
information on 'aboutness' that dc subject or some custom tag.

> For instance, suppose that I want to

There are two distinct forms of discourse going on here

- This entry is talking about some subject area or entity or resource.
It says something about something else. Being able to do this pretty
much why RDF was invented.

- This entry is classifiable under some subject area or topic or class.
It has something has sense of belonging or association to something
else. Being able to do this is pretty much why Topic Maps were invented.

Please, please, please, do not conflate these.

cheers
Bill

---

From: James M Snell <[email-masked]>
Date: Sat, 22 Oct 2005 07:49:07 -0700

>Please, please, please, do not conflate these.
Oh absolutely, I'm not trying to conflate 'em.  I want to find a 
solution to the first case ("this entry is talking about some subject 
area") that preferably does not involve invention or abuse of existing 
formats/tags.  I'm more than aware that RDF does this already but I not 
sure how that fact helps us in Atom (which is not RDF).

- James

---

From: Bill de hÓra <[email-masked]>
Date: Sat, 22 Oct 2005 17:10:52 +0100

> sure how that fact helps us in Atom (which is not RDF).

[RDF and TM were exemplary; cc'd to Henry/Danny]

Ah ok; I had read the proposal initially as subject classification
(dc:subject had me thinking that way).

If you're looking for a way to say this is entry is saying stuff about
something over there, then dc:subject and atom:category aren't a good
fit as they're more or less pointing the wrong way. rdf:about is the
closest analog in semweb land (plus it takes urls), but it's the wrong
thing here (I'll get to this).

 You could do any of the following:

 - define an atom:about tag or attribute that takes a URL.
 - use a @rel=about on a link tag

You can't use an rdf:about on the atom:entry element for this and that's
to do with entry metadata associations. What we want to say is that the
entry to talking about something else. With rdf:about the entry
*metadata* will become bound to the something else and not the entry
(which is messed up). The only sensible way I see is to work in terms of
the entry URI and the URI you're pointing at: 'entryURI isabout
someOtherURI' and define a new term for this purpose. Anyone that wants
to model this formally has enough information in the entry markup to
consistently generate the correct RDF statements out of band.

[I'm not suggesting RDF stuff for this - it's just very useful for
teasing out issues]

cheers
Bill