RE: PROV-ISSUE-277 (TLebo): Supporting property chains [Ontology]




I agree that the direction of properties is not an issue (and it wasn't
really me who raised this).  I didn't see it as an issue because:

- the properties are already in the right direction anyway (except for
defining prov:alternateOf from prov:specializationOf, and that would
never be agreed).

- I didn't know that there was a reluctance to define inverse


However, I don't agree that the direction never matters, because it
matters in OWL property chain axioms, and it seems worthwhile to have
property chains defined in the ontology and not just work around with
SPARQL queries.


The point that I did make, that was referred to here from
PROV-ISSUE-307, was that it would be necessary to specialise the
subproperties linking prov:Involvement to allow the direct properties to
be defined using property chains.  That has been resolved.




Stephen Cresswell 



From: [] On Behalf Of Daniel
Sent: 08 April 2012 20:23
To: Graham Klyne
Cc:; Cresswell, Stephen
Subject: Re: PROV-ISSUE-277 (TLebo): Supporting property chains


Hi all,
this issue is now pending review.
Stephen, if you still have concerns about the directionality of the
edges, could you please provide an example at [1]?.
If not, I would suggest to close this issue.



2012/3/4 Graham Klyne <>

I would hope this is a non-issue.  E.g. property paths in SPARQL include
provision for including inverse properties that are not explicitly

(I guess this is just a reminder, but the "direction" of RDF properties
places no technical constraint on accessibility - one can, in principle
(and in practice with most triple stores) traverse a property backwards
as easily as forwards.  Any need for explicit inverse properties is
almost entirely for human consumption (and authoring), and their absence
shouldn't constrain applications in any way.  Indeed, defining inverse
properties is more likely to create problems of incompatibility by
introducing different ways to express the same assertion.)


On 03/03/2012 16:28, Provenance Working Group Issue Tracker wrote:

PROV-ISSUE-277 (TLebo): Supporting property chains [Ontology]

Raised by: Stephen Cresswell
On product: Ontology

During our group telecon, someone (Stephen Cresswell?) mentioned a
concern that the directionality of some properties in prov-o would
inhibit the use of property chains.

Although "directionality" can be handled with owl:inverses, we are not
including many inverses in prov-o for brevity (however, we are
maintaining a component at [1]). Although "anyone" can define their own
inverse of a prov-o property to achieve their property chains, this will
inhibit interoperability.



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Received on Tuesday, 10 April 2012 12:01:13 UTC