Re: binary associatinons: Two roleSpecs or many more?

* Steve Pepper
| 
| If I have understood you correctly, you are asking whether a given
| association type implies one (and only one) corresponding set of
| role types (expressed using roleSpec elements in XTM).

This is an issue the spec is currently silent on. So far there's
nothing to disallow this. Whether it's good practice is something else
altogether, of course. What I think of this in general I am not sure
of. 
 
| I have wondered about this myself and I did actually experiment with
| it in the Italian Opera topic map.  There you will find an
| association type "written-by" that is used for *both* associations
| between operas and librettists *and* associations between literary
| works in general and writers. (Search for the string "AT:
| written-by" in either opera.hytm or opera.xtm.)

My opinion has been that this is really the same relationship: that
between a written work and its author, and so I don't think you should
distinguish the two. I suspect the reason was that you wanted to be
able to tell librettos and librettists from other written works and
authors, but the topic types let you do that with no help from the
association type.

| [written-by(opera, librettist) & written-by(work, writer)]
| 
| To be honest, I'm not too happy with this solution. My feeling is
| that if the set of role types are different then we are really
| talking about a different association type as well (even though its
| semantics may be very similar).

I think it's the other way around in this case.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >