[sc34wg3] Re: FYI: Yet another TMRM Formalization (well, not really)

[Robert Barta]

On Wed, Jul 14, 2004 at 07:48:03PM +0100, Martin Bryan wrote:
> Robert
> 
> >    http://astma.it.bond.edu.au/junk/tau-model.pdf
> 
> How can the Tau model be implemented in a manner that a computer can
> understand?

Martin,

Counterquestion: How can the natural numbers be implemented such that
a computer can understand?

The \tau model is a formalism, nothing else. It is not meant to
implemented as is, in the same way as relational databases do not
implement tables with the relational algebra.

What RDBMSes do is to incorporate 'knowledge about the relational
algebra, at least to a certain extend. This is also the intention
behind the path language, namely that engines can use it to perform
optimization steps during processing. The model is nothing else as a
basis to formulate the rules.

Whether we use it to define what TMQL statements actually do (formal
semantics), we (Lars and \me) have still to decide.

> How can a human specify an expression in the Map Path Language in a format
> that can be entered at a computer terminal using a standard QWERTY or AZERTY
> keyboard without invoking special character sets?

For example: Retrieve all author names from the map $m (whereever this comes from)

   ($m / is-author-of / author/bn @uc) 

----^  take the map

---------------------^ find all instances of this type (this give all association of this type)

-----------------------------^ in these associations find the author role(s)

-------------------------------^ get the basenames

-----------------------------------^ but only those in the unconstrained scope

If you look at our official

   http://www.isotopicmaps.org/tmql/uc-solutions.html

then you will find quite some examples with AsTMa? That one
uses path expressions.

> Martin Brayn

\roh :-)