[sc34wg3] RM: Mandatory role types?

Steve Pepper sc34wg3@isotopicmaps.org
Tue, 19 Nov 2002 09:17:58 +0100

At 00:23 19.11.2002 +0100, Lars Marius Garshol wrote:
>Steve Newcomb wrote:
>| Here's the rationale (at least as I see it):
>| (1) In the graph, all role types are mandatory because
>|     without them, there's literally no way to tell
>|     which role player is playing which role.
>Agreed, and this one on its own clinches it for me. Without roletypes
>you have a meaningless assertion.

Not meaningless, just incomplete. Why shouldn't it be possible
to express incomplete assertions in topic maps? For example:

(1) "A and B are related, but I don't know how"
     (no association type or role types; role players known)

(2) "A is married, but I don't know who his wife is"
     (association types and role types known; one role player unknown)

(3) "A and B are married, but I don't know who wears the trousers"
     (association type and role players known; role types unknown)

Another example of (3), from the Italian Opera topic map:

     "Puccini was the teacher of Ponchielli... Is was it Ponchielli
     that taught Puccini? Damned if I can remember!"

Why should the RM, the SAM or the syntax prevent us from expressing
these kinds of incomplete knowledge?


Steve Pepper, Chief Executive Officer <pepper@ontopia.net>
Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
Ontopia AS, Waldemar Thranes gt. 98, N-0175 Oslo, Norway.
http://www.ontopia.net/ phone: +47-23233080 GSM: +47-90827246