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

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"). 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.

I therefore proposed in my earlier emails
(1) to use an RDF-based language which is similar to RDFS/OWL,
    but not use exactly RDFS/OWL (different namespaces +
    specification of schema semantics needed for this)
(2) use an extension of N3 syntax to avoid completely ugly
    and lengthy syntax:

rif:Quantif sl:subClassOf rif:Condit .
rif:? sl:domain rif:Quantif ;
      sl:range rif:Var ;
      sl:minCardinality 1 .
rif:? sl:domain rif:Quantif ;
      sl:range rif:Condit ;
      sl:cardinality 1 .

could become something like this in "N3++":

rif:Quantif :: rif:Condit
  rif:? : rif:Var + ;
  rif:? : rif:Condit + .

This will also automatically buy us
- tool support (transformation to other syntaxes easily possible!)
- RDF syntax for rules (I didn't yet see any asn.06 syntax proposals
  for instances = rules)
- eat our own dog food

Michael

> 
>> To recap the earlier discussion, the motivations I saw for using asn06
>> instead of BNF were:
> 
> [Snipped good recap]
> 
>> Thinking over all this, I'm left with the conclusion that we can
>> just use OWL as the meta-language -- we can use OWL to declare what
>> parts a Horn rule has, etc.
> 
> I agree we can, though asn06 has the virtue of compactness. In
> particular expressing "list of" is a pain in OWL full (and worse in OWL
> DL).
> 
>> To play with this idea, I've been playing with transcribing Harold's
>> EBNF into OWL [2] and then programmatically turning it into asn06 and
>> (for folks who still want to use it despite the above reservationse)
>> EBNF.  In other words, one can see asn06 as a concrete syntax for a
>> sublanguage of OWL. 
> 
> Agreed.
> 
> 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 15:07:02 UTC