> On Thu, 11 Jan 2007, Kashyap, Vipul wrote:
> > Nigam,
> >
> > This is an interesting example...
> >
> >> Have an example for this one: If the instance is of a the class
> "Tumor"
> >> then
> >> on giving treatment it changes in size, shape etc, and might
> ultimately
> >> disappear. On each visit we are observing a different version of the
> tumor
> >> instance [in Tom].
> >
> > [VK] Clearly there is a longitudinal aspect to this as the state of the
> tumor
> > changes over time....
>   .. snip ..
> > IMHO, the former representation conveys more information and meaning...
> > So, it may make sense not to confound versioning with temporal
> progression...
> Spot on. I myself have had a hard time trying to grapple with the notion
> of allowing 'content' revision control to trickle into formal knoweldge
> representation and have yet to come across a scenario that demonstrates
> where this makes any sense.
> If a class has a particular 'definition' (i.e., the criteria for
> membership of its instances) at a particular time and that definition
> 'changes' then we are talking about a different class
> altogether not a 'version' of the same class - the extension of both
> classes are no longer the same.  Unless the definition change is
> annotative only and doesn't really have any 'logical' consequences.  In
> which case a SKOS, time-stamped annotation for a human reader is
> sufficient and what we really have in mind.

Hi Chimezie,

We are not talking about the Class here. Nothing is happening to the class
definition and its criteria for membership for an instance are unchanged.
It is the instance that changes its characteristics and now has
characteristics that can make it a member of a different class. The two
classes in question are unchanged.

So, my example still stands. The next version of the instance now belongs to
a different class (it is still Tom's tumor, now it might be TNM 3 instead of
TNM 1).... it is this change in instances that needs to be tracked.


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