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

From: McBride, Brian <brian.mcbride@hp.com>
Date: Wed, 5 May 2004 16:48:15 +0100
Message-ID: <E864E95CB35C1C46B72FEA0626A2E808028A344C@0-mail-br1.hpl.hp.com>
To: Aldo Gangemi <a.gangemi@istc.cnr.it>, "McBride, Brian" <brian.mcbride@hp.com>
Cc: SWBPD list <public-swbp-wg@w3.org>

 

> -----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
Received on Wednesday, 5 May 2004 11:48:40 UTC

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