[topicmapmail] <subjectIndicator> element not mandatory ?

[Thomas Francart]

Hi all

In the XTM DTD, the <subjectIdentity> element is not mandatory. It means
that a topic element can be created without any subject... which is rather
confusing.
In this case where no subjectIndentity is present, is the baseName playing
the role of the subject Identity ? (something having to do the topic naming
constraint ?) ?
I suppose there is a good reason why the subjectIdentity element is not
mandatory. Could anyone tell me why ?

Thanks

Thomas