[sc34wg3] revised draft Reference Model document N0298

[H. Holger Rath]

Hi,

A comment on wording in the dRM:

You say "Every topic map is a graph, and every assertion 
within a topic map is a subgraph within that graph."

If "graph" is understood as a collection of nodes
you can reach following the arcs starting at an arbitrary
node and "subgraph" is understood as a subset of this
collection, then I would say that "every assertion within
a topic map" is not necessarily a subgraph.

Why? Because assertions may define graphs which are not 
connected to other assertions/graphs. If we aim a mathematical
model for RM we should be also precise regarding graph theory.


An other comment on the different node types:

Are all node types of the same 'level' (I don't find
a better word here)? I mean from the programming point
of view it is obvious that X-, R-, A-, and P-nodes 
are first class objects with an id. But I am uncertain
if this is the case with the C-node? I assume C-node
were introduced to avoid hyper-edges connecting three 
nodes at once in the model (at least I can remember
a discussion about this). It is probably just a minor
point but worth to discuss.


And finally, a more academic question: 

Michel, SteveN  have you had HyTime or groves in mind and 
how the RM could be mapped to them? 

Regards,
--Holger

-- 
Dr. H. Holger Rath
- Director Research & Development -

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