Re: Requiring nodes to be blank Re: An alternative RDF

Timbl, all,

This new publication seems appropriate

Everything You Always Wanted to Know About Blank Nodes
http://www.websemanticsjournal.org/index.php/ps/article/view/365

Juan Sequeda
+1-575-SEQ-UEDA
www.juansequeda.com


On Fri, Jul 11, 2014 at 4:56 AM, Tim Berners-Lee <timbl@w3.org> wrote:

>
> On 2014-07 -10, at 14:17, Victor Porton <porton@narod.ru> wrote:
>
> > 10.07.2014, 16:05, "Michael Brunnbauer" <brunni@netestate.de>:
> >> Hello Victor,
> >>
> >> when using RDF, you cannot decree that certain entities have to be
> described
> >> using blank nodes. RDF users are free to choose between URIs or blank
> nodes and
> >> your app should be able to cope with both.
> >
> > My conclusion from this is that the RDF specification should be changed,
> so that an application would be able to demand that certain nodes are blank.
> >
> > And despite of that it is not already in the RDF standard, it seems that
> most of implementation already provide support for this: Using an RDF
> library I can tell which nodes are blank and which are not.
> >
> > Again: I demand to change the RDF specification. The rationale: Users
> should be able to construct an RDF file in such a way that loading more RDF
> files would not break its consistency. It is important.
>
> Victor,
>
> You are saying you want to force a structure like
>
>        <#office>   :manager [ :name "Bob";    ssn 123456789;   :dob
>  "1966-01-01"  ] .
>
> and not
>
>      <#office>   :manager  <#Bob>.
>      <#Bob>  :name "Bob";    ssn 123456789;   :dob  "1966-01-01"  .
>
> because you will be safe from encountering data from someone like
>
>      <#Bob>  :dob  "1966-05-06"  .
>
> which would lead you to conclude in total
>
>      <#office>   :manager  <#Bob>.
>      <#Bob>  :name "Bob";    :ssn 123456789;   :dob  "1966-01-01" ,
>  "1966-05-06"  .
>
> which is obviously inconsistent to anyone who knows :dob is functional.
>
> But if you have the blank node
>
>        <#office>   :manager [ :name "Bob";    ssn 123456789;   :dob
>  "1966-01-01"  ] .
>
> and someone also provides a graph
>
>         [ :ssn 123456789 ]  :dob  "1966-01-01"  .
>
> then your total data is anyway inconsistent to anyone who knows that :ssn
> is inverse functional.
> Your problem is not the shape of the graph, it is you have to decide which
> to believe.
> You have incorrect data.
>
> Depending on your application, your choice will mess up statistics in a
> study in a very minor way, or someone will be denied a job, or a plane will
> crash.  RDF won't tell you what to do in general.
>
>
> timbl
>
>