Re: asn06 take 2 (Abstract Syntax as a kind of ontology?)

Dave Reynolds wrote:
> Michael Sintek wrote:
>>
>> Dave Reynolds wrote:
>>> Sandro Hawke wrote:
>>>> Thinking more about the abstract syntax question, I find myself
>>>> wondering how an abstract syntax is really different from an ontology.
>>>> Is there any practical difference between an ontology of Horn rules and
>>>> an abstract syntax for Horn rules?  
>>> One possible difference is that in an abstract syntax you can say
>>> whether ordering is significant or not.  Sure, as you argue, one benefit
>>> is that you can say "ordering is not significant here" but you can also
>>> (at least in ASN.1) say "ordering *is* significant here". Or perhaps
>>> that is just a feature of ASN.1 rather than of abstract syntax notations
>>> in general.
>>>
>>> However, I think an ontology is closer to want we actually want for RIF
>>> and the only places we need to preserve order (e.g. in function/relation
>>> arguments) can be handled in an ontology.
>>>
>>>> If this is true, then OWL is a probably a good way to write down our
>>>> abstract syntax for RIF.
>>> That's also, sort of, what Michael Sintek was pointing out.
>>
>> With the big difference that I did not use OWL, since the open-world
>> semantics of OWL can result in unexpected results (like missing parts
>> of rules are automatically "inferred").
> 
> Understood, that's why I said "sort of".
> 
>> What we need is a more or
>> less closed-world, database schema like ontology language, so exactly
>> what RDFS was originally meant to be but is not any more.
> 
> Actually I think that is an issue of processing rather than of modelling.
> 
> We can use OWL to model what we say will be true of a rule, e.g. that it
> should have at least 1 consequent.
> 
> It's true that if one then applied a generic OWL inference engine to it
> one would infer the presence of a missing consequent rather than detect
> an omission. However, it is perfectly possible to also take the same
> modelling but apply closed world checking to instance data (we have
> tools that do this) and so achieve the desired schema-like behaviour.

IMHO, using OWL for modeling but interpreting it in a schema-like
way is not allowed -- this would mean we completely ignore the
official semantics. So if we send our RIF OWL ontology to other people
who use the official semantics, they will understand it in a
different way, and then we cannot use it as an interchange
language any more.

But, as Sandro already pointed out: we can *try* to use OWL with the
correct semantics, find the cases where some unwanted things
happen (if at all), and try to remedy them with additional
OWL axioms.

Michael

> 
> In that way one could use asn06 is a convenient syntax, translate to OWL
> to give a formal interchange, use that in closed world checkers for
> validation and get an instance serialization syntax (RDF as you say) for
> free.
> 
> Dave
> 
> 
> Dave
> 
> 

-- 
Michael Sintek -- DFKI GmbH, Kaiserslautern
http://www.michael-sintek.de -- sintek@dfki.uni-kl.de
phone: +49 631 205-3460 -- fax: +49 631 205-4910

Received on Tuesday, 21 November 2006 16:07:42 UTC