- From: Armando Stellato <stellato@info.uniroma2.it>
- Date: Sat, 4 Jan 2014 19:01:10 +0100
- To: "'Antoine Isaac'" <aisaac@few.vu.nl>
- Cc: <public-esw-thes@w3.org>
Dear Antoine, many thanks for your further reply. No need to be afraid of anything, actually your answer is complete as it represents the current situation: there is no enforcement by SKOSXL and it's a modeler's choice. I really had this doubt as I just remembered to have read something about the fact that SKOSXL labels should not be considered as independent lexical objects, thus hinting at the fact that any concept *should* actually have their own labels. But maybe it was just a paper on proposals and not a definitive word on the matter. Thanks again, I'll behave accordingly for the two cases I presented. Cheers, Armando > -----Original Message----- > From: Antoine Isaac [mailto:aisaac@few.vu.nl] > Sent: Saturday, January 4, 2014 10:40 AM > To: Armando Stellato > Cc: public-esw-thes@w3.org > Subject: Re: identity of SKOSXL labels > > Hello Armando, > > Sorry for having missed the other part of your question. > > I'm afraid I can't give you a complete answer however: to some extent it > depends on the nature of the knowledge/lexical system you want to > represent in SKOS. > > Imagine "foo" is the label you want to link to C1 and C2. Can this label get a > different set of attributes, when it is linked to C1 or C2? If not, then creating > and re-using one same URI (ex:foo) makes sense. Otherwise, if you think > "foo" may get different properties depending on its context of use, then you > must create two uris ex:foo-C1 and ex:foo-C2. > > I'm sorry not to give a more precise answer. The truth is, that at the time we > thought of SKOS-XL constraints, we foresaw both kinds of scenarios, and one > did not seem more legitimate for us to enforce/support it. > > Best, > > Antoine > > On 1/4/14 2:57 AM, Armando Stellato wrote: > > Dear Antoine, > > > > thanks a lot for the detailed background on it, it is really appreciated, as I > get more of the design principles behind SKOS/SKOSXL. > > However - and I hope not to be annoying - this clarifies things on one side > (the "what if" with existing labels), while still leaving some doubt on the > other (how to create labels). > > > > What I am asking is, with reference to the examples I made in my first > email: > > If I have to create skosxl:labels for concepts C1 and C2 (with identical literal > form "foo"), and if I'm willing to use URIs (not bnodes), should I create them > with *different* URIs? (is SKOSXL enforcing this? Is it a best practice? Is it > suggested but not mandatory?). > > > > The "identity is not guaranteed" statement with respect to skosxl:labels > with identical literalForms is clear to me, but formally, it does not entail an > answer to my question above (because it may hold to be true for very > different answers to that question). > > > > Many thanks, > > > > Armando > > > >> -----Original Message----- > >> From: Antoine Isaac [mailto:aisaac@few.vu.nl] > >> Sent: Thursday, January 2, 2014 9:39 PM > >> To: public-esw-thes@w3.org > >> Subject: Re: identity of SKOSXL labels > >> > >> Dear Armando, > >> > >> In SKOS-XL if two instances of xl:Label have the same literalForm, > >> then it does *not* follow that they are the same resource. > >> > >> This was in fact the subject of a lot of discussions in the making of > >> SKOS. We investigated quite in depth the alternatives, but couldn't > >> come with a strong motivation for coming with an 'identity rule'. In > >> fact it seems dangerous to enforce identify of resources from identity of > literalForm. > >> > >> Quoting this year's paper on the design of SKOS: > >> (http://dx.doi.org/10.1016/j.websem.2013.05.001) > >> [ > >> Two concerns that arose during discussions of modeling alternatives > >> for label relations were: identity conditions (When are two instances > >> of the class skosxl:Label the same individual?), and the formal > >> relationship between the class skosxl:Label and the set of RDF plain > >> literals (Can instances of the class skosxl:Label have more than one > >> literal form?). The working group decided to assert that instances of > >> skosxl:Label have exactly one literal form in order to avoid > >> ambiguity, but that sharing a common literal form should not be > >> sufficient to infer that two instances of the class skosxl:Label were > >> the same individual. In other words, two distinct instances of > >> skosxl:Label might have the same literal form; there is no one-to-one > mapping between the class extension of skosxl:Label and the set of RDF plain > literals. > >> ] > >> > >> I don't remember all the arguments then. But one was clearly that the > >> identity rule could harm interoperability with the kind of > >> ontology-lexicon models you're refering to. When mapping these models > >> to SKOS(-XL), it may make sense to represent as different resources > >> two lexicon entries that would have a same literal form. For example for a > words that is polysemous. > >> I'm not saying that this should be the reference representation of > >> such models in SKOS-XL, but we certainly didn't want to forbid such > scenarios! > >> > >> Also, from a pragmatic perspective, having the identity rule would > >> have made xl:Label really close from being a reified version of > >> rdfs:Literal. I.e., it would have practically allowed a trick to have > >> literals as subject of statements). This might have had some > >> consequences stretching quite far away the group's original mandate > >> (representing KOSs in a basic way, not offering alternative to low-level > RDF representation issues). > >> > >> Cheers, > >> > >> Antoine > >> > >> On 1/2/14 8:05 PM, Armando Stellato wrote: > >>> Hi Johan, > >>> > >>> yes my bad I forgot to mention also the Appendix B of skos core, > >>> which I > >> already read in the past, and in fact much of the doubts remain. > >>> > >>> By re-reading that section, I may confirm that it is not guaranteed > >>> that, > >> given two skosxl:Labels with the same literalForm, these are the same > >> resource. > >>> > >>> However, this “is not guaranteed” does not allow me to infer at all > >>> if > >> SKOSXL enforces that C1 and C2 **should** have their own distinct > >> labels, or if different modeling choices may allow the same URI to be > >> used for labels with same literal form belonging to different > >> concepts. The question is if, though reified, in a certain sense, the > >> label remains “an appendix of the concept” or has (may have) a life of its > own. > >>> > >>> The request may seem fussy, but here are two scenarios for which it > >>> is > >> important to determine the above: > >>> > >>> 1)Compatibility with ontology-lexicon models, such as the one being > >> developed here: http://www.w3.org/community/ontolex/ > >>> Clearly, if same entries from a lexicon can be attached to more > >>> concepts, > >> such models would be totally incompatible (not possible to specify > >> rdfs:subClassOf rels) with skosxl:Label, in the case that > >> skosxl:Labels have to be unique for each concept (i.e. even when > >> others with the same literalForm already exist) > >>> > >>> 2)SKOSXL development tools (such as http://vocbench.uniroma2.it/). > >> Which sort of integrity checks (out of the owl reasoning) should be > >> made while a skosxl:label is being created? Should different > >> “modalities” be selectable, or is there a clear design rule/best practice? > >>> > >>> Cheers, > >>> > >>> Armando > >>> > >>> *From:*Johan De Smedt [mailto:johan.de-smedt@tenforce.com] > >>> *Sent:* Thursday, January 2, 2014 2:47 PM > >>> *To:* 'Armando Stellato'; public-esw-thes@w3.org > >>> *Subject:* RE: identity of SKOSXL labels > >>> > >>> Hi Armando, > >>> > >>> You may want to have a look at the SKOS reference - > >> http://www.w3.org/TR/skos-reference/#xl > >>> > >>> In particular Section B.2.4.1 (and less relevant for your issue: > >>> B.3.4.2) > >>> > >>> Kind Regards, > >>> > >>> *Johan De Smedt * > >>> > >>> /Chief Technology Officer/ > >>> > >>> // > >>> > >>> mail: johan.de-smedt@tenforce.com <mailto:johan.de- > >> smedt@tenforce.com> > >>> > >>> mobile: +32 477 475934 > >>> > >>> mail-TenForce > >>> > >>> *From:*Armando Stellato [mailto:stellato75@gmail.com] *On Behalf Of > >> *Armando Stellato > >>> *Sent:* Thursday, 02 January, 2014 13:46 > >>> *To:* public-esw-thes@w3.org <mailto:public-esw-thes@w3.org> > >>> *Subject:* identity of SKOSXL labels > >>> > >>> Dear all, > >>> > >>> suppose in SKOS I have: > >>> > >>> mythes:C1 skos:prefLabel “foo” > >>> > >>> mythes:C2 skos:altLabel “foo” > >>> > >>> In SKOSXL, should I have something like: > >>> > >>> mythes:C1 skosxl:prefLabel mythes:foo > >>> > >>> mythes:C2 skosxl:altLabel mythes:foo > >>> > >>> mythes:foo skosxl:literalForm “foo” > >>> > >>> or like this? : > >>> > >>> mythes:C1 skosxl:prefLabel mythes:foo_1 > >>> > >>> mythes:C2 skosxl:altLabel mythes:foo_2 > >>> > >>> mythes:foo_1 skosxl:literalForm “foo” > >>> > >>> mythes:foo_2 skosxl:literalForm “foo” > >>> > >>> in other words, is SKOSXL enforcing in any way that concepts which > >>> are > >> expressed through same lexicals, should have in any case their own > >> labels for them or, on the contrary, a same label should be used…or > >> these is no indication about that? > >>> > >>> In http://www.w3.org/TR/skos-reference/skos-xl.htmlthere is no hint > >> about that, but I almost recall that I read/heard somewhere that the > >> skosxl reification of the labels is *not* meant to “unify” labels > >> with identical literalForms under a same URI, thus the general rule > >> is to use in any case a different label URI for each concept. > >>> > >>> Could anyone shed some light on this? (and, in case, point me to the > >> appropriate link if there is any…) > >>> > >>> Cheers, > >>> > >>> Armando > >>> > >>> P.S: in the example, I put a prefLabel for C1 and an altLabel for > >>> C2, but > >> assuming the specific properties being used do not affect the answer > >> to my question, so it could be skos:***Label. Pls let me know if this > >> matters anyhow. > >>> > > > >
Received on Saturday, 4 January 2014 18:01:43 UTC