[xtm-wg] Graph again ... (and BTW, PSI again)

["Bernard Vatant" <universimmedia@wanadoo.fr>]

Murray

I just wanted to translate the feeling of the mathematicians, which are not
completely mine, because I'm an uncomplete mathematician ... I am on the
challenging task of bridging communities, remind you.
My bridge to them was indeed that XTM syntax is what one can find the most
simple as far as syntax is concerned, and since I could understand it and
find it quite simple - as well as Steve and Michel's model for that matter -
*they* could understand it.
I've followed and quite understood I think the reason for every bit of this
syntax and agree with you on the feeling it's easy to use. And I'd gladly
share the coffee before attacking any piece of RDF, but let me the entire
pot, two or three cups will not do :)

I agree a Topic Map is not "simply" a graph. But it's maybe very well
represented as a "colored graph" or "labeled" graph. Which means the
different kinds of nodes can be characterised by their "color" or "label" or
"flavor" whatever you like to call them, like a-node and t-node and s-node
... and certainly other need to be introduced, so that we do not have graph
inconsistencies like a node attached to a single arc, like in first analysis
<roleSpec> appears to be, if you don't create a proper m-node. Things like
that - more in the announced document.

Not in a corner on my mind the least intention to shed blood over the DTD.
It should definitely be graph-representable as it is, like I think every
possible DTD. Simply my hunch the graph will be more complicated that if it
has been thought to begin with. That is : optimize and make consistent a
graph structure out of the very core TM concepts, and then write the DTD and
syntax out of it. Since we've made the road the other way round, forget
about what-we-should-have-done.

Concerning the "magic" algorithms. Mathematics are open source. Every bit of
it. Is not that great ? Three centuries of work to get the Fermat's theorem
demonstration, and not even a single license to use it. Well but ... I
suppose implementations of those algorithms are not indeed open source, but
I really don't know much about that. What I understand of what is
implemented in Mondeca - which is very little, because I am not a developer
at all - is that it was a huge and still ongoing work putting these
algorithms into a proper effective "graph manager".

Anyway. I feel now that something has to get out of all that, but I'll be
off that forum now till Saturday if I want to have my paper on PSI ready for
Montreal submission. And BTW, the question I asked four days ago about PSI
for PSI seems to have been swept away by the flow of messages about "the
graph". Repeat : How do I do when I publish a PSI to declare it's intended
to be one ?
(see propositions in my previous message about it)

Cheers

Bernard

----- Message d'origine -----
De : "Murray Altheim" <altheim@eng.sun.com>
À : <xtm-wg@yahoogroups.com>
Envoyé : jeudi 29 mars 2001 03:39
Objet : Re: [xtm-wg] A challenge on "the graph"


> Bernard Vatant wrote:
> [...]
> > What can I can say NOW is, out of an afternoon on the phone with the
graph
> > people (BTW not "professeurs" but "chercheurs")
> >
> > The model they propose is ridiculously simple. Just a translation of
nodes
> > and arcs into ... vertices and edges :)
> > They say indeed : Topic Maps are so simple. Why did you complicate them
with
> > all that unnecessary twisted syntax ?
>
> Because topic maps are not an implementation of graph theory, as can be
> claimed (as has been) of RDF. The "unnecessary twisted syntax" expresses
IMO
> very well the *specific* semantics of the various relationships in a topic
> map document, with all its nooks and crannies. We could have created a
more
> generalized syntax like RDF, where everything was "in a namespace" and the
> syntax itself provided only the rudiments of tuples. RDF is a general
purpose
> tool, XTM is a tool to represent, well, topic maps. It just so happens
that
> the word chosen to represent a topic map "in memory" is "graph," and it is
> demonstrably possible to represent a topic map as a graph. But a topic map
> is not *simply* a graph, and for purposes of interchange we wanted to make
> explicit in syntax the various topic map features.
>
> While syntax has a lot to do with markup style, I for one have little
> difficulty in creating or "reading" XTM syntax, while most RDF requires at
> least two or three cups of coffee to comprehend, especially when one isn't
> using a well-known flavour like Dublin Core.
>
> > The nodes of the same type have the same color. So have the arcs of the
same
> > type. Some TM elements will be nodes, some other will be arcs. There
will be
> > basic rules on the colors of nodes and arcs, and that's all there will
be
> > ... In fact, it's as simple and obvious as Topic Maps looked to me ...
> > before I began to look into the syntax :o)
> >
> > And they claim : " The graph modeling shows some inconstencies and
> > shortcomings of the XTM syntax model and the DTD. But it's very easy to
> > clean that". And I said : *Please* - there has been enough of blood and
> > tears - don't *ever* mention the DTD.
>
> While I'm not interested in making any changes to the XTM DTD, as this
> would seriously damage further development of XTM (and I'd definitely
> begin looking for other work), I'd be still interested in understanding
> their issues. If you don't want to start a bloodbath online, send this
> to me privately.
>
> > BUT ... they know how to put these sets of colored nodes and arcs in a
> > system and have algorithms to spider the graph and query and retrieve
> > amazing things you just can't do in a relational data base, like : "Take
any
> > (A,B) in a set of entangled genealogical trees. Find every couple made
of a
> > descendant of A married to a descendant of B". Or : "Find me a family
where
> > all members of three following generations were born, married and dead
in
> > the same county". Weird things like that. And they claim these
algorithms
> > have been around for ages.
>
> If they're open source, let me at them. This is precisely what Sam, I and
> others have been asking about.
>
> > And they claim it's not academic work, and that Francfort's Airport
traffic
> > and New York's garbage collection, among others, are working with
> > implemented models grounded in graph theory. And they've brought some
> > interesting features into Mondeca software, too, as some of you know ...
> >
> > So we have at hand a conceptual model and a processing model, and query
> > algorithms, all grounded in the most universal representation language I
> > know, and I think less controversial than any of those passing by lately
:
> > mathematics ...
> >
> > What more ? We'll have a F2F meeting next week to put all that down in a
> > single document for the community use.
> > I propose to write down that document in such a way that it meets the
> > mathematicians' requirements and the eagerness of XTM community to
> > understand them.
>
> Well, I for one definitely look forward to seeing this document.
>
> Murray
>
>
...........................................................................
> Murray Altheim
<mailto:altheim&#x40;eng.sun.com>
> XML Technology Center
> Sun Microsystems, Inc., MS MPK17-102, 1601 Willow Rd., Menlo Park, CA
94025
>
>       In the evening
>       The rice leaves in the garden
>       Rustle in the autumn wind
>       That blows through my reed hut.  -- Minamoto no Tsunenobu
>
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