Re: SKOS transitive hierarchical relations

Hi Fred,

One use case for broaderTransitive is the one of a data consumer willing to use the information that a concept C is broader than concept A, whatever other concept exist "between them" in the conceptual hierarchy. This is especially useful for information retrieval.
One use case for broader is to be able to easily access the "individual hierarchy steps" which are present in a thesaurus. For example, when you want to display a thesaurus tree, it makes a big difference to know that there is a concept B which is broader than C but narrower than A.

Now, if a data publisher releases only broaderTransitive, this is a pity because information is lost, as explained in my other mail today [1]. I know that in many cases you could retrieve the "original" skos:broader statements from skos:broaderTransitive one. But:
- this would require an algorithm which is not so trivial
- in some cases, the assumptions on which such an algorithm would typically rely on are in fact wrong. These cases are very rare, but still...

So considering all these things, we opted for the current structure. Believe me, we have considered the issue quite seriously in the Semantic web Deployment group... I know that it may look sub-optimal, but this is really the best we could came up with at the time.

Cheers,

Antoine

[1] http://lists.w3.org/Archives/Public/public-esw-thes/2012Jan/0007.html


> Hi Antoine,
>
>> In fact having thesauri published with only skos:broaderTransitive (and not skos:broader) is quite bad practice. Where have you seen this?
>
> Except the fact that it is stated in the specification that by convention it shouldn't be done, could you elaborate a little bit more one this assertion: "having thesauri published with only skos:broaderTransitive (and not skos:broader) is quite bad practice". So, what makes it a bad practice, and what are the core reasons. This may be illustrate with some usecases.
>
>
>> Indeed, the original idea is that the vocabulary providers would start publish assertions with skos:broader/narrower.
>> Then broader/narrowerTransitive statements could be infered, and materialized either by the thesaurus publisher or by a data consumer.
>> Note that there is no real interpretation freedom here. The transitive properties are defined as super-properties of the unspecified ones. This means that everytime you have a skos:broader statement between two concepts, the semantics of SKOS imply that there is a skos:broaderTransitive statement holding as well.
>
> Yes, but if I know they are transitive as the thesaurus publisher, why couldn't I use skos:broaderTransitive directly? I have some issues understanding why this convention has been put in place in the SKOS spec (probably by lack of knowledge on some of the underlying usecases of SKOS).
>
>
> Thanks!
>
> Take care,
>
> Fred
>

Received on Wednesday, 4 January 2012 18:41:00 UTC