- From: Enrico Franconi <franconi@inf.unibz.it>
- Date: Thu, 30 Jan 2014 18:55:45 +0100
- To: Aidan Hogan <aidan.hogan@deri.org>
- CC: PAUL WARREN <paul.w.warren@btinternet.com>, Dave Reynolds <dave.e.reynolds@gmail.com>, "semantic-web@w3.org" <semantic-web@w3.org>
On 30 Jan 2014, at 16:29, Aidan Hogan <aidan.hogan@deri.org> wrote: > Paul, I think Dave's advice is sound: as tempting as it might be, it is *not* helpful to talk about OWL subsumption using phrases like inheritance. This will do more harm than good (esp. since the counter-examples will heavily outweigh the examples). Not really. "Inheritance" (in the object oriented sense) holds true in DL: a property of all the *objects* of a superclass is inherited to all the *objects* of the subclass. So, if class C is subsumed by class D, then if all the objects in class D have a property P, then all the objects in class C have the property P. This is true in Java, description logics, OWL, Smalltalk, CLOS, etc. cheers —e. > > Hence why the "inheritability" of different OWL features isn't documented (and nor should it be). > > If you want a non-technical means of introducing the features of OWL, examples using IF -- THEN -- (i.e., rules) will give a sound but incomplete picture. Studying the rules in OWL 2 RL/RDF is a great starting point for anyone wanting to learn a bit about what the *key* entailments of the OWL (2) features are (and without having to get into the formal semantics): > > http://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules > > The OWL features mean more than what's represented in these rules, but IF you can understand these rules, THEN you'll have a working knowledge of OWL. > > (Unfortunately though, I feel we're fighting a losing battle with regards the didactic aspects of OWL in the broader sense of it being a *Web standard*. Perhaps the battle is even already lost.) > > Best, > Aidan > > > On 30/01/2014 05:43, PAUL WARREN wrote: >> I have come across this problem recently in some work I have been doing >> investigating people's understanding of OWL constructs. You can't >> assume that property characteristics are inherited - some are (e.g. >> functionality), some aren't (e.g. transitivity and symmetry). But I >> have found no reference in any documentation to this fact. >> >> Cheers, >> >> Paul Warren >> >> ------------------------------------------------------------------------ >> *From:* Dave Reynolds <dave.e.reynolds@gmail.com> >> *To:* semantic-web@w3.org >> *Sent:* Wednesday, 29 January 2014, 17:05 >> *Subject:* Re: Deduced property >> >> OWL, and the underlying logic, are quite different from object oriented >> modelling so using terms like "inheritance" can trip you up. Especially >> when it comes to property axioms. >> >> In the RDF/OWL way of thinking then a property corresponds to set of >> pairs of things that are related by the property. So saying >> >> :hasParent rdfs:subPropertyOf :hasAncestor >> >> means, and only means, that the set of pairs of things related by >> :hasParent is a subset of the set of pairs of things related by >> :hasAncestor. >> >> It's sets all the way down :) >> >> Dave >> >> On 29/01/14 16:47, Jean-Claude Moissinac wrote: >> > OK >> > I really thought that the transitivity was inherited. I will try to find >> > where and how the non-inheritance is specified >> > Thank you >> > >> > -- >> > Jean-Claude Moissinac >> > >> > >> > >> > 2014-01-29 Matthew Horridge <matthew.horridge@stanford.edu >> <mailto:matthew.horridge@stanford.edu> >> > <mailto:matthew.horridge@stanford.edu >> <mailto:matthew.horridge@stanford.edu>>> >> > >> > Hi Jean-Claude, >> > >> > Asserting >> > >> > :hasParent rdfs:subClassOf :hasAncestor >> > >> > and >> > >> > :hasAncestor rdf:type owl:TransitiveProperty >> > >> > does not mean that :hasParent is also transitive. Transitivity >> > isn’t “inherited” down the property hierarchy, so it’s possible to >> > have a non-transitive sub property of a transitive super property. >> > >> > Cheers, >> > >> > Matthew >> > >> > On 29 Jan 2014, at 08:30, Jean-Claude Moissinac >> > <jean-claude.moissinac@telecom-paristech.fr >> <mailto:jean-claude.moissinac@telecom-paristech.fr> >> > <mailto:jean-claude.moissinac@telecom-paristech.fr >> <mailto:jean-claude.moissinac@telecom-paristech.fr>>> wrote: >> > >> >> No, it's not the answer because hasAncestor is transitive and >> >> hasParent isn't... >> >> (I've a lot of similar situations) >> >> >> >> -- >> >> Jean-Claude Moissinac >> >> >> >> >> >> >> >> 2014-01-29 Richard Cyganiak <richard@cyganiak.de >> <mailto:richard@cyganiak.de> >> >> <mailto:richard@cyganiak.de <mailto:richard@cyganiak.de>>> >> >> >> >> Jean-Claude, >> >> >> >> You’re looking for this (in Turtle syntax): >> >> >> >> :hasParent rdfs:subClassOf :hasAncestor. >> >> >> >> (Don’t try to read or write RDF/XML directly. You’ll go mad. >> >> Use the friendly syntaxes such as Turtle, or graphical tools.) >> >> >> >> Best, >> >> Richard >> >> >> >> >> >> On 29 Jan 2014, at 16:18, Jean-Claude Moissinac >> >> <jean-claude.moissinac@telecom-paristech.fr >> <mailto:jean-claude.moissinac@telecom-paristech.fr> >> >> <mailto:jean-claude.moissinac@telecom-paristech.fr >> <mailto:jean-claude.moissinac@telecom-paristech.fr>>> wrote: >> >> >> >> > Sorry if my question is very naive, but I'm stuck on this >> >> for a while >> >> > if I go to examples in the document >> >> http://www.w3.org/TR/2009/WD-owl2-primer-20090421/ >> >> > I just want to add the following axiom (expressed here in my >> >> syntax) >> >> > if >> >> > ?s :hasParent ?f >> >> > Then >> >> > ?s :hasAncestor ?f >> >> > >> >> > I've checked a lot of documents and I don't figure how to do >> >> it (directly in XML/RDF or interactively with Protégé) >> >> > >> >> > Thank you in adavnace for your help >> >> > >> >> > -- >> >> > Jean-Claude >> >> > >> >> >> >> >> >> >> > >> > >> >> >> >> >
Received on Thursday, 30 January 2014 17:56:18 UTC