W3C home > Mailing lists > Public > public-data-shapes-wg@w3.org > January 2015

Re: shapes and classes: different

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Mon, 26 Jan 2015 10:20:50 -0800
Message-ID: <54C68582.2070808@gmail.com>
To: Irene Polikoff <irene@topquadrant.com>, Jerven Tjalling Bolleman <jerven.bolleman@isb-sib.ch>
CC: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

The defining characteristic of shapes is that they are provided with
conditions that determine which objects belong to them.  Saying that a
square is subclass of a rectangle and that squares have their width and
breadth equal doesn't make square a shape even though it may be the case
that objects belonging to square are precisely those objects that have an
rdf:type link to  it. Saying that squares are precisely those rectangles
whose width and breadth are equal does make square a shape as this provides
a set of conditions that determine when an object is a square.

peter


On 01/26/2015 09:24 AM, Irene Polikoff wrote:
>> 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.
> 
> Irene
> 
> On Jan 26, 2015, at 11:12 AM, Jerven Tjalling Bolleman 
> <jerven.bolleman@isb-sib.ch <mailto:jerven.bolleman@isb-sib.ch>> wrote:
> 
>> I really can't help myself...
>> 
>> On 26/01/15 15:12, Peter F. Patel-Schneider wrote:
> 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
>>> 
>> 
>> -- ------------------------------------------------------------------- 
>> Jerven Bolleman                        Jerven.Bolleman@isb-sib.ch 
>> <mailto: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
>> <http://www.isb-sib.ch> - www.uniprot.org <http://www.uniprot.org> 
>> Follow us at https://twitter.com/#!/uniprot 
>> -------------------------------------------------------------------
>> 
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iQEcBAEBAgAGBQJUxoWCAAoJECjN6+QThfjz+V4H/iV8kUJVuwihUMSbYifPAiqx
hfVmsHUiDbtON9BisNq9eJJJkJ1GOewrCI/KXZYJ9sDaZJLPZzTigV2mpuxu1xRr
vfp2yDT6oYnCFXZ19aZNrYCzfS7RrEvLZS8o+ZLZQENSK1djyEp/duBeVJYy5mBa
p4RB556xun192EJLyBxynO2A7PfmuGMFKgiYvQvQYd8hp9UCZ4fpBkMPOEaG+QfX
1iKVM0BrnIPJy4kqJCEffB9QGLeoHMUdbsG8gzx150lche/YYzWcaN07L7i3xq7H
CseP9ZGt/PJJ0awZecL+I3RZ4Yv82qRTttAS8tz6cEzwwkEszQ4tJ8aC7E/aHrQ=
=1H8T
-----END PGP SIGNATURE-----
Received on Monday, 26 January 2015 18:21:20 UTC

This archive was generated by hypermail 2.3.1 : Monday, 26 January 2015 18:21:21 UTC