Re: Why do we name nodes and not edges?

Hi Melvin,
before everybody confuses you too much. Here some simple facts:
1. Yes, it is possible in RDF to use edge ids
2. If you do please be careful with numbers. The RDF/XML serialization 
format is based on XML which can't handle XML tags starting with numbers:
So <edge:123456  rdf:resource="http://ex.org/ex10"  /> will bite you 
some day.
Use either <edge:id_123456  or <edge123456:_ 
xmnls:edge123456="http://fulluri"
3. Whether this is best practice is worthy of discussion (see the TL;DR 
thread)
4. Fact is, that there are use cases for this and *outside* Semantic Web 
community it is quite normal to have edge ids. See for example the ISO 
standard Topic Maps http://en.wikipedia.org/wiki/Topic_Maps and LISP as 
mentioned by Ivan.
5. When using them you have to decide whether you mean the "edge type" 
or rather try to encode a "statement id" . The former would allow you 
using the same edge id with different subject/object (this is what is 
traditionally used). The latter would fix the subject and object.
6. You can avoid reification with using edge ids as statement ids and 
track provenance. (It has other disadvantages, but it might tackle your 
requirements alright.)

Hope I could help,
Sebastian


Am 25.07.2012 17:07, schrieb Melvin Carvalho:
> Sorry if this topic has been covered before, but I have a question based on
> the axioms of the web, in particular:
>
> *Axiom 0a: Universality 2    Any resource of significance should be given a
> URI.
> *
> In this case we consider the web to be a directed graph (of nodes and
> edges), where a *node* corresponds to a *resource* but edge does not.
>
> We are encouraged to make nodes universal by giving them a URI.
>
> Why dont edges get the same treatment, ie encouragment to give it a
> (universal) name.  Is it even practical?
>
> I know there's such thing as reification but that seems to be unpopular
> (maybe before my time).
>
> I'm just curious as to whether this seems asymmetrical, that nodes are
> seemigly treated in one way, and edges in another?
>


-- 
Dipl. Inf. Sebastian Hellmann
Department of Computer Science, University of Leipzig
Events:
   * http://sabre2012.infai.org/mlode (Leipzig, Sept. 23-24-25, 2012)
   * http://wole2012.eurecom.fr (*Deadline: July 31st 2012*)
Projects: http://nlp2rdf.org , http://dbpedia.org
Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
Research Group: http://aksw.org

Received on Thursday, 2 August 2012 10:00:45 UTC