- From: Chris Dollin <chris.dollin@epimorphics.com>
- Date: Thu, 20 May 2010 13:59:45 +0100
- To: semantic-web@w3.org
On Thursday 20 May 2010 01:20:54 pm Jitao Yang wrote:
> for example:
> "... the formula DescPr(*d, p, o*) in *L*, asserting that object *o* is a
> value of property *p* in description *d*. ..."
>
> and we have:
> DescPr(*d, p, o*)
> DescPr(*d1, p, o1*)
>
> the above formula could be represented by RDF like:
>
> :d
> a :DescPr_description ;
> :has_property :p .
>
> :d1
> a :DescPr_description ;
> :has_property :p .
>
> :p
> a :DescPr_property ;
> :has_value :o ;
> :has_value :o1 .
That would be wrong, because if d has_property p which has_value
o, it /also/ has_property p and value o1. Similarly for d1. Hence the
RDF representation does not encode the two formulae given; it
encodes /4/ formulae, dpo, dpo1, d1po, d1po1.
> The class DescPr_description and DescPr_property are defined in RDFS:
Only if you use "define" in a very weak sense. Admittedly that's the
best you can do in RDFS (and OWL), but what you can't do is provide
any non-comment specification of how these properties are something
to do with the formulae.
> of course, the triples can go back to the logical representation, in the
> above example.
No; that representation doesn't allow you to recover all /and only/ the
original formulae.
> and there are errors in the above RDFS, since based on the above RDFS: d =
> d1,
No. RDFS doesn't impose identity constraints like that.
> but in fact no.
>
> Use your idea:
>
> case3:
>
> [a Formula; relation p; on d; value o].
> [a Formula; relation p; on d1; value o1].
>
> case 1:
>
> p assertion [on d; value o], [on d1; value o1]
>
> but, how to translate your representation to Turtle?
They're pretty much in Turtle; you need to choose prefixes
for the terms I've written as "relation", "on", "value", and
"Formula", but that's about it.
> because your representations are not triples.
Consider
p assertion [on d; value o], [on d1; value o1]
Let's pick namespaces and prefixes to illustrate:
@prefix eh: <http://rdf.epimorphics.com/chris/examples#>.
@prefix some: <http://example.com/rdf#>.
some:p eh:assertion
[eh:on some:d; eh:value some:o]
, [eh:on some:d1; eh:value some:o1]
.
That's all triples, using Turtle syntax for multiple objects
(ie: S P O1, O2, O3 abbreviates S P O1. S P O2. S P O3)
and blank nodes ([...]) with multiple property-values
(S P1 O1; P2 O2 abbreviates S P1 O1; S P2 O2).
Not counting prefixes or extensions for quads, if you can
write it in Turtle, it's triples.
--
RDF is not /the/ answer. RDF is /an/ answer. - Arcadian
Epimorphics Ltd
Registered address: C/O Robson Taylor, Froomsgate House, Bristol
Registered number: 7016688
-----------------------------------------
--
RDF is not /the/ answer. RDF is /an/ answer. - Arcadian
Epimorphics Ltd
Registered address: C/O Robson Taylor, Froomsgate House, Bristol
Registered number: 7016688
Received on Thursday, 20 May 2010 13:01:17 UTC