Re: Why Literals should be unique and why this is a serious issue

Fine, you are pointing the SemanticWeb Stack, OWL over RDF, which is 
actually very comparable to TCP over IP (for instance IP does not 
garanty delivery, while TCP does)

So IP is very flexible, just like RDF right ? So you say to use OWL if 
it suites you to cover the flexibilty of RDF. Im fine with that, and I 
absolutely agree that we need flexibility in the down layers and so in RDF.

But there is a dramatic error. In the SemanticWeb, what counts is the 
Knowledge you define (in an Ontology). On top of your Knowledge Base you 
are free to choose a specific inferencing so you can produce more 
knowledge - in example transitifity of subClassOf produces additional 
triples to cover all over-under classrelations. But (and here is the 
error) you are NOT able to extract additional information / knowledge 
out of an Ontology, if the ontology is not suitable.

Try to get additional subClassOf Information out of an Ontology, which 
does not contain any Class (and subClassOf) definitions. Try to to 
identify Resoures on Values in an Ontology, which does not specifiy 
InverseFunctionalProperties. The required results you will get will be 
*0*, simlpy because the Information is not there (and therefore no 
inferencingrules can be applied). You are not able to cover the 
simplicity of an RDF Ontology using OWL Inferencing.

I know that (in your reply) you said: " in which case RDF is not for 
you, but OWL might be something more akin to what you want". This is 
very correct. But what are you going to do, with ontologies which are 
already described using "super simple" and "super flexible" pure RDF ? 
How are you going to cooperate RDF Ontologies with Ontologies, which are 
well defined using lets say OWL Full (incl. InverFunctProperties).

Before hearing people telling: Of course you can cooperate in some way - 
*Yes*. Dont forget that we are basicly talking about 
resource-dublication (see first email-post).

We feel very comfortable "now" (and me as well), but currently 
everythink is still very simple. Will you keep the overview if thausands 
of Ontologies (multi) interconnect to each ??
Will you tell people who described their resources using RDF: "Hey you 
guys, you must use OWL now, we not more precision now !" ?

Without wanting to disrespect any of you guys, I think that 
*same-concept dublication* is is not taken serious enough and IMHO this 
can become very tricky in the long-term.


If you mean that the SemanticWeb Stack is not supposted, for this kind 
of circumstances -  I think you might be correct!!! The question is, if 
this is a good solution.
We will be forced to cover such circumstances in an higher level of 
abstraction...someday. If you seek for appropriate contributions on this 
field (such as research-papers) Im prommising you that this is not fun, 
since automious merging of equiavalent knowledge is a very difficult 
topic. The problems which could arise in this field, might even not be 
solvable.

So is there a chance to prevent dublication-hell earlier ? Do you think 
I´m a panic-maker ? Maybe you are, but I still have not heard 
constructive suggestions on how to solve this problems. I´m still 
looking forward to it.


Do I think there is a solution ? In my IMHO yes, but this might also 
include a refactoring of the SemanticWeb Stack and its definition. (you 
can also see previous posts on this topics for some suggestions)


best regards,
Andreas



Jeroen van der Ham schrieb:

>
> Andreas Andreakis wrote:
>
>> The question is how can we prevent same-concept dublication ?
>>
>
> Excuse me for being blunt, but I really don't see why you would want 
> or need this in RDF.
>
> If you really want to prevent duplication, you have to use OWL Full, 
> as someone already explained. I don't see why or how you would prevent 
> this in RDF.
>
> IMO RDF was designed to be a loosely formatted way of describing 
> resources. There is no limit to what you can describe or how. This 
> also means that you are almost completely agnostic of what is being 
> described. And this means that there is no way to really prevent a 
> 100% fault-proof method of preventing concept duplication, unless you 
> are really meticulously defining what you are talking about, in which 
> case RDF is not for you, but OWL might be something more akin to what 
> you want.
>
> And about rdf:id, it has been posted on this list before, but it 
> really doesn't mean much to declare something rdf:id. If you use it 
> and convert it to triplets, then the fact that it should be a unique 
> id is lost.
> It only gets in your way if you want to extract things from the 
> XML/RDF notation, because you have to account for both rdf:id and 
> rdf:about.
>
> Jeroen.
>
>