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?

see Rules for Assertions (parid9005)