Re: Is there a name for this one weird trick?

These particular examples *are* cardinality constraints but they are
applied to a single subject as applied to a class.  Also the thing I am
trying to name is the mechanism for

"making a statement about all the set of  all ?s ?p values" for a given (?s
?p)

for instance

:Deadpool_Movie :mikeApproves :actor .

to state that Mike approves the actor list for the Deadpool movie.  It
competes with other ways of making "statements-about-statements" except it
only lets you talk about ?s ?p pairs rather than ?s ?p ?o triples.  It also
competes with the conventional uses of schemas,  except schemas tend to be
a way of

"making statements about ?s ?p pairs where ?s a ?c" parameterized by (?c
and ?p)

For instance if we were round tripping data to and from Java objects,  and
the target object looks like

class Car  {
   Set<Key> key;
}

at some point the system knows it is producing a certain Java object and it
as clear as day that it is going to populate a Set object for key.  That
knowledge is implicit in the Java reflection data and could be represented
in RDF if that was desired.

In the case of DynamoDB,  for instance,  there is a distinction between a
String and a Set<String> that is necessary to make when you create the
object,  but this is not a function of a "class" but rather something which
can be different for every instance because it isn't enforced by a schema.

On Sun, Sep 4, 2016 at 6:23 AM, Graham Klyne <gk@ninebynine.org> wrote:

> Not sure if this helps... but OWL can define a notion of a singleton class
> - e.g. https://lists.w3.org/Archives/Public/semantic-web/2014Nov/0100.html
> .
>
> I understand this is sometimes used for modelling specific-values in OWL
> or Description Logic domain descriptions.
>
> Or maybe what you describe is simply a cardinality constraint:
> http://www.w3.org/TR/2012/REC-owl2-primer-20121211/#Property
> _Cardinality_Restrictions
>
> #g
> --
>
>
> On 04/09/2016 01:33, Paul Houle wrote:
>
>> Imagine I have some facts about an instance such as
>>
>> :instance07 :composedOf :Lead .
>>
>> and then I say something like
>>
>> :instance07 :singleValued :composedOf .
>>
>> to distinguish the case of "a single valued property" from "a set of of
>> property values which just happens to have one member".  The difference
>> doesn't usually matter in RDF-world but if you have to round trip with
>> Lucene or DynamoDB you can attach supplementary data with the
>>
>> "make a statement about an ?s ?p pair by writing ?s ?p1 ?p"
>>
>> This permits writing
>>
>> :John :hasNo :sibling .
>>
>> This is parallel to how people typically write RDF so it does not get in
>> the way,  but it queries just fine with SPARQL, Jena Rules and such.
>>
>> Is there a name for this trick?
>>
>>
>>


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