[Beware: Topic Maps ahead.]
Once you reach a certain age, you seriously ask yourself whether this has been be all: wealth, fame and many beautiful women.
It is the time when you look for a more integrated meaning in the universe. A meaning which transcends all levels of abstraction. And a processing model which gets rid of the silly separation between programming language and semantic data store with its static knowledge.
Ever since I met Jan Schreiber in Oslo a while back I had this itch that someone should write a C library for TMRM. Not only to host maps in proxy form, but more importantly to have a fast evaluation mechanism for myTMQL path expressions.
I was waiting for an opportunity to pack this into one of the paid projects, but that opportunity never arose.
Every now and then I see typical stack diagrams depicting the standards landscape in TM and in RDF land.
While the relationship between TMRM and TMDM is mostly represented correctly, that is, that TMDM constructs can be couched in terms provided by TMRM, the rest of the usual diagrams does not reflect my understanding.
The editors of TMRM have concocted a new TMRM version. It will be soon on its way into the innards of the ISO repository.
Notable decision from Oslo (April 2008) was to factor out the TMDM mapping and add it, maybe as addendum later.
Now that we know how proxies form atomic blocks to build maps, we can start to navigate through a given map. Since the structure is so minimalistic we can expect that there are only a few ways to get around a map.
Let us first assume that we have a single proxy in our hand:
beard => white,
beard => long }
4 Corners of the Compass
One thing we could be interested in is to find all it keys of that proxy. Now, for this operation TMRM has
In our series about TMRM we have covered so far:
- how they can be simply organized into subject maps, and what merging of proxies means and what views on maps one can produce.
Apart from the bottom proxy (remember, the one with no properties at all), there was so far no need to predefine any proxies. As soon as we want TMRM to honor subclassing of concepts and also to understand a type-instance
Continuing with our tour through the TMRM we can now look into complete maps. Once we have namely collected a number of TMRM proxies into a set, we can actually call that already a subject map.
A decent implementation of subject maps will maybe take care that every proxy label used within a proxy inside a particular map has a corresponding proxy in the same map, but the TMRM itself does not concern itself with this.
Generic Merging = Set Union
Since at this level maps are simply sets, we can
Those of you who got curious from my ultrashort intro into the Topic Maps Reference Model may want follow me here when I write a bit about my interpretation of the TMRM.
Best is to forget topics, names, occurrences and associations as defined in TMDM for the moment. TMRM abstracts all of these into one, atomic concept: the proxy. We will return to TMDM later.
Here again is the proxy spider:
When you are using Topic Maps, then you most likely are familiar with the TMDM, the data model for Topic Maps. It defines items such as topics with their various identification mechanisms, and names and occurrences and associations. TMDM is quite easy to wrap your mind around.
Still, TMDM may not sit at the very center of the Topic Map paradigm in sense that the selection of constructs such as topic, occurrence, name and association is - while anthropocentrically useful -