Nodes will have more than one "subject": they will
have multiple assertions made about them. For example, I can think of
cases where I am the guarantor of my my own validity (who reported Martin
Bryan as being sick last week, Martin Bryan!), which may need to be
expressed in some topic map someday. So then I'll have to distinguish the
logical me from the physical one to make the nodes unique. (Assertion =
[was-sick: Martin Bryan] [reported-by: Martin Bryan])

> I completely agree. SLUO can never be more than a (very important) design
> guideline. One can never be sure subjects are actually represented by only one
> node (topic) since human knowledge is only partial...
A quick comment on this issue:
Subject Identity Discrimination Properties allow the RM (an RM
conformant application) to determine whether two nodes 'have the same
subject' by comparing the values of their SIDPs according to the rules
defined in the governing TM Application Definition (for example the SAM).
If the result of this comparision is that the nodes represent the
same subject, the RM requires the nodes to be merged. It does not
require the nodes to be merged if 'subject equality' cannot be
calculated on the basis of the SIDP values and their semantics
as defined in the application definition.
I think that this is sufficiently expressed by the merging rules, but
possibly an addition to 3.4.1 could further clarify this. ( Steve? )