Re: Some interesting things that show up when using a reasoner to classify schema.org

> On Jan 22, 2015, at 3:48 AM, Martin Hepp <martin.hepp@unibw.de> wrote:
> 
> Ah! Yes, that is also a viable way, much better than my proposal! The key advantage over my proposal is that the Python code for generating the documentation does not need to change - rangeIncludes effectively becomes rangeHint and domainIncludes domainHint, and the integrity constraint axioms will be modeled using rdfs:___domain and rdfs:range with complex class definitions, as in this example (from GoodRelations):
> 
> gr:condition a owl:DatatypeProperty;
>  rdfs:comment "A textual description of the condition of the product or service, or the products or services included in the offer (when attached to a gr:Offering)"@en;
>  rdfs:___domain  [ a owl:Class; 
>        owl:unionOf (gr:Offering gr:ProductOrService) ];
>  rdfs:isDefinedBy <http://purl.org/goodrelations/v1>;
>  rdfs:label "condition (0..1)"@en;
>  rdfs:range rdfs:Literal.

The difference between using the unionOf and domainIncludes variation is that domainIncludes is open, and allows other vocabularies to extend the ___domain for their purpose (as, for example, yoursports.com does). Whereas, unionOf uses an rdf:List, which can't be extended. Other than the extensibility issues, then ___domain/rangeIncludes are essentially the same as unionOf.

Gregg

> Martin
> 
> --------------------------------------------------------
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
> 
> e-mail:  martin.hepp@unibw.de
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> 
> 
> 
> 
> 
> On 22 Jan 2015, at 12:21, ☮ elf Pavlik ☮ <perpetual-tripper@wwelves.org> wrote:
> 
>> On 01/22/2015 11:36 AM, Martin Hepp wrote:
>>> Hi elf:
>>> 
>>> On 22 Jan 2015, at 11:26, ☮ elf Pavlik ☮ <perpetual-tripper@wwelves.org> wrote:
>>> 
>>>> On 01/21/2015 05:21 PM, Martin Hepp wrote:
>>>>> Hi Dan,
>>>>> A hands-on solution would be to add two internal "annotation" properties "rangeHint" and "domainHint" that allow explicitly triggering the display of certain schema.org types in the documentation.
>>>>> 
>>>>> 
>>>>>  <div typeof="rdf:Property" resource="http://schema.org/purpose">
>>>>> ...
>>>>>    <span>Range: <a property="http://schema.org/rangeHint" href="http://schema.org/MedicalDevicePurpose">MedicalDevicePurpose</a></span>
>>>>>    <span>Range: <a property="http://schema.org/rangeIncludes" href="http://schema.org/Thing">Thing</a></span>
>>>>>  </div>
>>>>> 
>>>>> 
>>>>> The documentation could then list the formal range (Thing) and popular types for the range (e.g. MedicalDevicePurpose)
>>>> 
>>>> http://schema.org/rangeIncludes
>>>> Relates a property to a class that constitutes (one of) the expected
>>>> type(s) for values of the property.
>>>> 
>>>> http://schema.org/domainIncludes
>>>> Relates a property to a class that is (one of) the type(s) the property
>>>> is expected to be used on.
>>>> 
>>>> AFAIK both of those don't cause any inferences so in a way they already
>>>> act in a similar way to rangeHint and domainHint which you propose.
>>>> 
>>>> If rangeIncludes and domainIncludes have some *formal* consequences I
>>>> think they could use bit more of documenting.
>>>> http://schema.org/docs/datamodel.html
>>> 
>>> You are right that the documentation does not say so, but I assume the Google Structured Data Testing Tool and production systems inside Google/Bing/Yahoo/Yandex use rangeIncludes and domainIncludes to assess the validity of data.
>>> 
>>> The beginning of the discussion was that Simon reported a range of e.g. "Place OR Restaurant" as an inconsistency, and I replied that such patterns are in use in order to trigger more specific type hints.
>>> 
>>> If rangeIncludes and domainIncludes were just for type hints, we would not need to fix such ___domain or range specifications.
>>> 
>>> In my understand, rangeIncludes and domainIncludes were introduced in order to avoid the unintuitive semantics of ___domain and range in RDFS and OWL, and to be able to list alternative classes without defining a complex class that is the union thereof. 
>>>> 
>>>> BTW James M Snell in Activity Streams 2.0 uses owl:unionOf to specify
>>>> multiple types for ___domain and range. Maybe (___domain/range)Includes could
>>>> act just as hints and schema.org could use something similar for
>>>> expressing *formal* consequences?
>>> 
>>> GoodRelations has been using this pattern since ca 2008, too - as a means to stay within OWL without triggering unintended additional type inferences.
>>> 
>>> But still this pattern does not allow giving hints to users on popular specializations of the formally defined type or types.
>> 
>> I wanted to suggest that - instead of adding yet another informal way of
>> specifying ___domain and range using *Hint. We could acknowledge current
>> *Includes properties as informal hints intended for broad community of
>> people, who develop various tools for publishing data on the web. Then
>> we can add proper, formal definitions only relevant for much smaller
>> group of developers who work on validators etc. This way we could use
>> more complex constructs from OWL and improve alignment with broader
>> Linked Data ecosystem :)
>> 
>> 
>

Received on Thursday, 22 January 2015 18:28:47 UTC