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Re: [WNET, PORT, OEP] Synset's and Classes - dumb question

From: Guus Schreiber <schreiber@cs.vu.nl>
Date: Thu, 06 May 2004 23:35:12 +0200
Message-ID: <409AAF90.5010108@cs.vu.nl>
To: "McBride, Brian" <brian.mcbride@hp.com>
Cc: Aldo Gangemi <a.gangemi@istc.cnr.it>, SWBPD list <public-swbp-wg@w3.org>

This thread suggests to me that we should really first focus on the
"as-is" conversion, without trying to interpret WordNet. Subsequently,
people can publish there interpretations. I do not expect this WG to 
publish a single ontologyical interpretation of WordNet, although it 
would be nice, of course.

As Aldo said, the purpose of my earlier note [1] was just to show how an 
"as-is" conversion could look like, using the WordNet v2.0 Prolog 
distribution as input. The main decision concerns the representation of 
the words in a synset, either as literal values or as individuals. The 
rest appears to me to be rather straightforward. This is what I call 
low-hanging fruit. It gives SW developers a common reference point.

Guus

[1] http://lists.w3.org/Archives/Public/public-swbp-wg/2004Apr/0014.html

McBride, Brian wrote:

>>-----Original Message-----
>>From: public-swbp-wg-request@w3.org 
>>[mailto:public-swbp-wg-request@w3.org] On Behalf Of Aldo Gangemi
>>Sent: Wednesday, May 05, 2004 4:09 PM
>>To: McBride, Brian
>>Cc: SWBPD list
>>Subject: Re: [WNET, PORT, OEP] Synset's and Classes - dumb question
>>
>>
>>Hi Brian,
>>
>>At 14:05 +0100 5-05-2004, McBride, Brian wrote:
>>
>>>Looking through the discusion on representing WordNet, I've 
>>
>>been trying to
>>
>>>understand the relation between wordnets, thesauri and ontologies.
>>
>>you can download various papers and tutorials from our site that 
>>explain distinctions: http://www.loa-cnr.it.
>>BTW, the basic issues are:
>>
>>1) ontologies in the *formal* sense are axiomatic theories, while 
>>thesauri and wordnets are only graphs (tree structures, forests), 
>>whose primitives have no explicit formal semantics
>>2) primitives assumed in those graphs can be given a formal semantics 
>>by making appropriate interpretations and adjustments, therefore 
>>wordnets and thesauri can be transformed into formal ontologies
>>3) wordnets assume typical primitives coming from linguistics, while 
>>thesauri assume primitives coming from terminology, library 
>>management, etc.
>>4) a conservative alternative in porting thesauri and wordnets to OWL 
>>is considering them just "structures" (e.g. RDF models), and not 
>>ontologies.
> 
> 
> Thanks, Aldo.  That is helpful.
> 
> 
>>>Is there a consensus view on the relationship between a 
>>
>>wordnet synset and
>>
>>>the class the synonyms names, i.e. is the synset containing 
>>
>>the word 'dog'
>>
>>>necessarily owl:sameAs the class of dogs?
>>
>>owl:sameAs applies to owl:Individuals, so you are asking a meta-level 
>>question :)
> 
> 
> Oops.
> 
> 
>>OK, my position is that 
> 
> 
> Is that representative of consensus in the community?
> 
> - provided that we want to transform a 
> 
>>wordnet into a formal ontology - the semantic interpretation of 
>>"synset" is that of an equivalence class of words/terms according to 
>>a common intended meaning. Since "having a unique intended meaning" 
>>is also applicable to classes, the *default* mapping of synsets is to 
>>owl:Class.
> 
> 
> Hmm.  That logic seems vulnerable to the observation that properties too
> have a unique intended meaning, as do instances.
> 
> So what are the instances of the class you have in mind?  The term 'synset'
> suggests it is intended to denote a set of synonyms.  Are you suggesting
> that the instances of the class are words, with the word 'dog' being of type
> Synset(Dog).  Or are they dogs?
> 
> 
> 
>>On the other hand, not only classes have a unique intended meaning, 
> 
> 
> You were ahead of me :)
> 
> 
>>but also individuals, and as a matter of fact, many synsets refer to 
>>individuals like "Italy" or "Cicero". That's why "synset" hasn't a 
>>precise mapping to formal ontologies. 
> 
> 
> Hmm, it seems to a rather ignorant me that equating the obvious synset
> containing 'dog' to the class of dogs is a bit dubious in theoretical terms.
> Equating it to the class of synonyms of (one sense of) 'dog' seems like a
> more accurate representation of the WordNet.  And that would be a precise
> mapping to a formal ontology, just a different kind of mapping, right?
> Later one could consider the relation between the synset containing 'dog'
> and the class of dogs.  But that is not a sameClassAs relationship.
> 
> 
> Then, your dog example is 
> 
>>correct, but not "necessarily".
>>
>>
>>>Also, does WordNet have synsets for relations?  Do such synsets have
>>>hypernyms or hyponyms?  If so is rdfs:subClassOf rather 
>>
>>rdfs:subPropertyOf
>>
>>>correct?
>>>
>>
>>WordNet does not distinguish explicitly synset "types".
> 
> 
> Guus' proposal did.
> 
> 
>>Some of them 
>>(specially some verbs) can be  considered as potential 
>>owl:ObjectProperty, and obviously have hypernyms or hyponyms.
>>But I do not encourage this kind of investigation, since for each 
>>owl:ObjectProperty you can get an owl:Class that reifies it, and this 
>>is what natural languages do often. E.g., is "GIVE" (as a 
>>verb-synset) more mappable to an owl:Class (being an action), an 
>>owl:ObjectProperty (someone gives something), or some OWL-DL 
>>construct that implements an n-ary relation (someone gives something 
>>to someone else in a certain way, etc., see Natasha's draft)? We have 
>>good motivations for each of those interpretations.
> 
> 
> I shall look forward to the draft.  Is it a development of Guus' proposal?
> However, what you have said so far is causing me to lean towards the view
> that trying to treat wordnet as an ontology is a bit iffy and encoding
> WordNet in an SW language might be more appropriate.  It would be good to
> have practical criteria such as concrete use cases or effects on software to
> guide a decision.
> 
> 
>>My suggestion is to map any WordNet synset to either an owl:Class or 
>>to an owl:Individual.
> 
> 
> Is that a fixed mapping, or based on some criteria?
> 
>  owl:ObjectProperty instances should be provided 
> 
>>on other grounds, for example:
>>
>>a) some "lexical relations" already in WordNet as such, like meronymy 
>>and troponymy
>>b) external sources, like core ontologies
>>c) some synsets, used as heuristics
>>d) ontology learning techniques
> 
> 
> I didn't follow that.  I guess I need to see the proposal.
> 
> 
>>hmm, I stop here, since what I am saying will be part of the report 
>>to be delivered next week.
>>BTW, there seems to be here a nice overlap between [WNAT] (and 
>>[PORT]), and [OEP], because the interpretations I have given about 
>>wordnets and thesauri can be considered preliminary sketches for 
>>ontology "reengineering" patterns, which can be a subclass of 
>>ontology desing patterns.
> 
> 
> Hmm, we seem to have a tradeoff between just getting a common encoding of
> WordNet and tackling some more 'interesting' issues of ontology
> reengineering.  Do I recall correctly that phase 1 is just about the
> encoding?
> 
> Best Wishes
> 
> Brian
> 

-- 
Free University Amsterdam, Computer Science
De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands
Tel: +31 20 444 7739/7718
E-mail: schreiber@cs.vu.nl
Home page: http://www.cs.vu.nl/~guus/
Received on Thursday, 6 May 2004 17:36:16 UTC

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