Re: From syntactic to interpreted triple

> On 21. Jan 2021, at 15:35, Olaf Hartig <olaf.hartig@liu.se> wrote:
> 
> Hi Thomas,
> 
> You are raising an interesting point that I was also thinking about recently, 
> and I believe I have a solution.
> 
> First of all, regarding terminology, our groups' earlier discussions related 
> to this topic used the terms "referential opacity" and "referential 
> transparency" for what you call "syntactic triple" and "interpreted triple" 
> now.
> 
> The proposed semantics adopts referential opacity. From my understanding, in 
> comparison to a semantics that adopts referential transparency, adopting 
> referential opacity (as in the proposed semantics) is less restrictive in the 
> sense that it does not rule out the possibility to use referential 
> transparency for selected cases. In other words, by using referential opacity 
> as a basis (i.e., for the semantics of RDF*), on top of this basis you may 
> still define specific cases for which the additional nested triples may be 
> derived that you would expect under referential transparency. In contrast, if 
> referential transparency is used as a basis, which says that such additional 
> nested triples can be derived for all cases, then it is not possible to define 
> on top of this basis that there are cases for which the additional triples 
> should actually not be derived. At least, that's what I had understood from my 
> discussions with Pierre-Antoine and Dörthe (please feel free to confirm or 
> correct me on this).

Seems to be the same understanding as mine.

> Given this understanding, you may indicate the cases in which you want to use 
> referential transparency on top of a referential opacity semantics by using 
> specific properties that you introduce for this purpose. For instance, you may 
> introduce a property denoted by the URI ex:statedBy and define that 
> referential transparency can be used for nested triples that have this 
> property in their predicate position. This way, related to your example, if 
> you have a nested triple 
> 
> <<:cars :are :bad>> ex:statedBy :Alice 
> 
> you can derive the following triple.
> 
> <<:automobiles :are :bad>> ex:statedBy :Alice 
> 
> So, while the semantics of RDF* adopts referential opacity, you can build on 
> it and define cases in which you want to have referential transparency.

But doesn’t this mean that in every case that you want to comment on a triple with referential transparency you have to define a new property with those specific semantics? That would seem like an outrageous demand to me.

And even then: how would you define such a property? It probably should be a subproperty of the property that you intend to use. That seems to need a new property like
    
 rdf*:isSubpropertyWithOpaqueSemanticsOf

or even

 rdf*:isSubpropertyWithOpaqueSemanticsInDomainOf
 rdf*:isSubpropertyWithOpaqueSemanticsInRangeOf
 rdf*:isSubpropertyWithOpaqueSemanticsInDomainAndRangeOf

as different embedded triples in subject and object position might have different semantics. So you’d get three subproperties per any property from any established vocabulary, right? Maybe not *all* of them but certainly not a few in between.

If this is indeed your proposal then I think you’ll have to come up with something better. Or please explain what you meant instead.

Thomas



> Best,
> Olaf
> 
> 
> On torsdag 21 januari 2021 kl. 13:40:56 CET thomas lörtsch wrote:
>> [I hope I’m using the right terminology in the right way. Advice is
>> welcome.]
>> 
>> The proposed semantics defines that the embedded triple refers to a triple
>> on the syntactic level, not in the realm of interpretation. In defense of
>> this rather peculiar arrangement Pierre-Antoine and Dörthe argued that
>> going from the syntactic to the interpreted triple is always possible
>> whereas the other way round it is not: once a triple is part of the
>> interpretation we can not know what its original syntactic structure was.
>> That’s true (at least in any normal setup) but let's assume I’d like to
>> annotate not the syntactic triple but the interpreted triple. What would I
>> actually have to do to construct a reference to an interpreted triple from
>> an RDF* embedded triple?
>> 
>> 
>> Lets for example assume someone published the triple
>> 
>>  :cars :are :bad .
>> 
>> As he published that statement on the semantic web we can assume that his
>> intend was to refer not only to :cars but just as well to :automobiles,
>> :voitures etc. Now if we want to comment on that general interpretation of
>> this statement, irrespective of the concrete vocabulary used, irrespective
>> of any syntactic specifics, how would we do that? The proposed semantics of
>> 
>>  << :cars :are :bad >> :a :disputedClaim .
>> 
>> doesn’t cover this very common case as the embedded triple only refers to
>> that very specific syntactic form. From this RDF* statement we couldn’t
>> infer that
>> 
>>  << :automobiles :are :bad >> :a :disputedClaim .
>> 
>> even if we were using a reasonably complete mapping of car related
>> vocabiularies. Adding all those derivable embedded triples to the database
>> is not a viable option as it would increase operational costs enormously.
>> We need a way to derive a reference to the interpreted triple from the
>> syntactic triple that the RDF* embedded triple represents. But how?
>> 
>> 
>> Thomas
> 
> 
>

Received on Friday, 22 January 2021 12:14:15 UTC