Re: [topicmaps-comment] Re: RDF/Topic Maps: late/lazy reification vs.early/preemptive reification

[Piotr Kaminski <piotr@ideanest.com>]

LMG wrote:
> I think SRN is right here: the way to model this is to use a ternary
> association, with the sponsor playing the third role.

Perhaps.  This leads to another usage question:  how do you decide when
it's better to have a single association with multiple players for one
role, and when it's better to have a bunch of n-ary associations (for
fixed n, usually 2), with each role played by only one player?  (i.e. in
my own terminology, when should you use a single collector vs. a
collection of relators)

In any case, I think the problem is still valid; it's conceivable that I
want to superimpose the sponsorship information on a foreign topic map
without modifying it (e.g. so I can take advantage of future updates
thereof).  If the original map didn't consider sponsorship, then the
single collector approach would've been a valid (and, from what I've seen,
preferred) one.

> In PMTM4 there is no t-node that represents each association role
> (please correct me if I am wrong). This is in my opinion a serious
> weakness of PMTM4, and it's related to the problem of the three-legged
> arc.

Aha!  That's what I thought, but I wanted to take some more time to digest
the heavy prose.  Has this criticism been made before, and was there a
response?  (If the response is just "don't model things that way" then I
don't buy it.)

        -- P.

--
  Piotr Kaminski <piotr@ideanest.com>  http://www.ideanest.com/
  "It's the heart afraid of breaking that never learns to dance."