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RE: shapes and classes: different

From: Irene Polikoff <irene@topquadrant.com>
Date: Mon, 26 Jan 2015 18:22:32 -0500
To: "'Eric Prud'hommeaux'" <eric@w3.org>
Cc: "'Jerven Tjalling Bolleman'" <jerven.bolleman@isb-sib.ch>, "'Peter F. Patel-Schneider'" <pfpschneider@gmail.com>, "'RDF Data Shapes Working Group'" <public-data-shapes-wg@w3.org>
Message-ID: <1b2301d039be$f9ae3ee0$ed0abca0$@topquadrant.com>
This is not really a question to me, but to the group that designed and
maintains this vocabulary. It is a pretty "unwieldy" one although may be it
has gotten cleaner lately? The use case it's designed for was, I believe,
for people to publish information about themselves.  I don't know what
constraints are needed for that.

Other vocabularies that have been designed for a broad use, often have
constraints. SKOS has a number of constraints defined in its documentation.
Folks that do FIBO seem to be pretty clear on their definitions and
constraints. I believe this is true for any other group that develop
vocabularies. They are the ones to decide on the constraints.

If I was to simply brainstorm, there could be a constraint that says that
the range of foaf:knows must be a foaf:Person. Or a constraint that says you
can't use both foaf:family_name and foaf:surname. It is either one or the
other. Or a constraint that there can be only one foaf:birthday and it must
be a date.

What is the significance of this question?

Irene

-----Original Message-----
From: Eric Prud'hommeaux [mailto:eric@w3.org] 
Sent: Monday, January 26, 2015 4:50 PM
To: Irene Polikoff
Cc: Jerven Tjalling Bolleman; Peter F. Patel-Schneider; RDF Data Shapes
Working Group
Subject: Re: shapes and classes: different

* Irene Polikoff <irene@topquadrant.com> [2015-01-26 12:24-0500]
> > Your word shape is my word owl:Class.
> 
> +1
> 
> So, the simplest solution is not to have a new thing called Shape.
> 
> Another option may be to use it as a type so that some classes can be of
type Shape as well as Class.
> 
> This seems to be unnecessary though as every class is already a shape. At
minimum, even if there are no other constraints declared for a class, it
says that all instances belonging to it must have a certain type triple. If
there is a class :Person, then its instances must have :Person1 a ::Person
triple (whether it is asserted or inferred, doesn't matter). A very
minimalistic data shape, but still a shape.

What constraints would you put on a reusable class like foaf:Person?


> Irene
> 
> > On Jan 26, 2015, at 11:12 AM, Jerven Tjalling Bolleman
<jerven.bolleman@isb-sib.ch> wrote:
> > 
> > I really can't help myself...
> > 
> >> On 26/01/15 15:12, Peter F. Patel-Schneider wrote:
> >> -----BEGIN PGP SIGNED MESSAGE-----
> >> Hash: SHA1
> >> 
> >> The most important aspect of classes is that you state that objects 
> >> belong to them.  If you don't state that objects belong to X, X is not
a class.
> >> 
> >> The most important aspect of shapes is that you provide conditions
stating
> >> precisely when an object belongs to them.   If you don't provide
conditions
> >> stating precisely when an object belongs to X, X is not a shape.
> >> 
> >> Having shapes also be classes implies that you state that objects 
> >> belong to shapes.  Having classes also be shapes implies that you 
> >> provide recognition conditions for classes. Both situations are 
> >> possible, but both have consequences.
> > Your word shape is my word owl:Class. Allowing class membership
inference from recognition conditions is as normal as class member ship
assertion directly in the data. But I am absolutely flabbergasted that I am
having this argument with one of the OWL2 editors!
> > 
> > Basically I am reading your response as class membership only inferred
is "shape membership". Class membership asserted is not "shape membership".
Or paraphrased: Shapes only allows triples with the shape:member predicate
(IMO equivalent to rdf:type) to be inferred and not asserted.
> > 
> > 
> >> 
> >> peter
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> >> 
> > 
> > --
> > -------------------------------------------------------------------
> > Jerven Bolleman                        Jerven.Bolleman@isb-sib.ch
> > SIB Swiss Institute of Bioinformatics  Tel: +41 (0)22 379 58 85
> > CMU, rue Michel Servet 1               Fax: +41 (0)22 379 58 58
> > 1211 Geneve 4,
> > Switzerland     www.isb-sib.ch - www.uniprot.org
> > Follow us at https://twitter.com/#!/uniprot
> > -------------------------------------------------------------------
> > 

-- 
-ericP

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Received on Monday, 26 January 2015 23:23:16 UTC

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