Re: Temporal validitity of subject indicators?

Andrew S. Townley wrote:

> Hypothetically, let's say you're defining a topic for "Bob's Garage" and you know that Bob's been in business for 20 years with the same telephone number.  A perfectly good choice for a subject indicator might be his website, http://bobsgarage.com or even his telephone number (via RFC2806), tel:+19135551234.  You know that these might have the added advantage of appearing near any other references to Bob's Garage so you pick one or both.
> 
> Fast forward to time t+n, and Bob's goes out of business, the hosting company redirectsbobsgarage.com to a link farm/advertising page and Bob's phone number gets reassigned to something else.  The problem is that your topic map (authors and users) don't really have any idea that this has happened, so they get new data with these references, but the references now indicate different subjects.  At time t+n+1, someone discovers that the subject indicator is no longer valid and needs to update the map.  You might also just happen to have some old data around that needs to either be referenced or used to rebuild the map.  Some of that "old data" may also be in the form of serialized topic maps.
> 
> What do you do?

You realize that 'http://bobsgarage.com' was *not* a perfectly good choice for a subject indicator.

Generally, your idea reminds me of an open space session that Lutz Maicher and Xùan Baldauf were giving at one of the TMRA conferences (2008?). They suggested to scope subject identifiers. I have never seen a similar emotional reaction to an open space session and it was not positive. There was a follow up discussion on this list, if i remember correctly. This shows you that this is an important and delicate subject which touches the heart of the community. I thought it is a good idea, since i became aware of the semiotic problems that embrace any semantic technology during my work on Topincs. The following resources helped me to understand the subject matter better:

* Sebeok, Thomas: Communication Measures to Bridge Ten Millenia
* http://www.topincs.com/people/robertcerny/758
* http://www.topincs.com/people/robertcerny/1036

On the other hand i think that the TMRM does it right, by leaving the actual source of information untouched and by putting the algorithms to reach subject identity decisions into legends. Actually when developing my idea of content and glue topic maps i looked at the TMRM and wondered why it does not have this problem. My answer was that it actually lets people use the identifiers they are most comfortably with (their own) and delays the burden of deciding on subject identity to the last possible moment (late merging). This is what content and glue topic maps is about.

Best,

Robert