I don't know if these are useful, but if we go two steps from the fundamental categories on the English Wikipedia we find several loops. Knowledge contains information and information contains knowledge, for example. Not allowing loops might force you to have to give different ranks to two categories that are equally important.


Date: Tue, 7 May 2013 16:41:45 +0200
From: hellmann@informatik.uni-leipzig.de
To: wikidata-l@lists.wikimedia.org
Subject: Re: [Wikidata-l] Question about wikipedia categories.

Am 07.05.2013 14:01, schrieb emw:
"Yes, there is and should be more than one "ontology", and that is
already the case with categories, which are so flexible they can loop
around and become their own grandfather."

Can someone give an example of where it would be useful to have a cycle in an ontology? 

Navigation! How else are you going to find back where you came from ;)
Wikipieda categories were invented originally for navigation, right?  Cycles are not soo bad, then...
Now we live in a new era.
-- Sebastian


To my knowledge cycles are considered a problem in categorization, and would be a problem in a large-scaled ontology-based classification system as well.  My impression has been that Wikidata's ontology would be a directed acyclic graph (DAG) with a single root at entity (thing).


On Tue, May 7, 2013 at 3:03 AM, Mathieu Stumpf <psychoslave@culture-libre.org> wrote:
Le 2013-05-06 18:13, Jane Darnell a écrit :

Yes, there is and should be more than one "ontology", and that is
already the case with categories, which are so flexible they can loop
around and become their own grandfather.

To my mind, categories indeed feet better how we think. I'm not sure "grandfather" is a canonical term in such a graph, I think it's simply a cycle[1].

[1] https://en.wikipedia.org/wiki/Cycle_%28graph_theory%29


Dbpedia complaints should be discussed on that list, I am not a
dbpedia user, though I think it's a useful project to have around.

Sorry I didn't want to make off topic messages, nor sound complaining. I just wanted to give my feedback, hopefuly a constructive one, on a message posted on this list. I transfered my message to dbpedia mailing list.



Sent from my iPad

On May 6, 2013, at 12:00 PM, Jona Christopher Sahnwaldt <jc@sahnwaldt.de> wrote:

Hi Mathieu,

I think the DBpedia mailing list is a better place for discussing the
DBpedia ontology:
https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
Drop us a message if you have questions or concerns. I'm sure someone
will answer your questions. I am not an ontology expert, so I'll just
leave it at that.

JC

On 6 May 2013 11:01, Mathieu Stumpf <psychoslave@culture-libre.org> wrote:
Le 2013-05-06 00:09, Jona Christopher Sahnwaldt a écrit :

On 5 May 2013 20:48, Mathieu Stumpf <psychoslave@culture-libre.org> wrote:

Le dimanche 05 mai 2013 à 16:28 +0200, Jona Christopher Sahnwaldt a

The ontology is maintained by a community that everyone can join at
http://mappings.dbpedia.org/ . An overview of the current class
hierarchy is here:
http://mappings.dbpedia.org/server/ontology/classes/ . You're more
than welcome to help! I think talk pages are not used enough on the
mappings wiki, so if you have ideas, misgivings or questions about the
DBpedia ontology, the place to go is probably the mailing list:
https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion


Do you maintain several "ontologies" in parallel? Otherwise, how do you
plane to avoid a "cultural bias", and how do you think it may impact the
other projects? I mean, if you try to establish "one semantic hierarchy
to rule them all", couldn't it arise cultural diversity concerns?


We maintain only one version of the ontology. We have a pretty diverse
community, so I hope the editors will take care of that. So far, the
ontology does have a Western bias though, more or less like the
English Wikipedia or the current list of Wikidata properties.

JC



I can't see how your community could take care of it when they have no
choice but not contribute at all or contribute to one ontology whose
structure already defined main axes. To my mind, it's a structural bias, you
can't go out of it without going out of the structure. As far as I
understand, the current "ontology"[1] you are using is a tree with a central
root, and not a DAG or any other graph. In my humble opinion, if you need a
central element/leaf, it should be precisely "ontology"/representation,
under which one may build several world representation networks, and even
more relations between this networks which would represent how one may links
concepts of different cultures.

To my mind the problem is much more important than with a local Wikipedia
(or other Wikimedia projects). Because each project can expose subjects
through the collective representation of this local community. But with
wikidata central role, isn't there a risk of "short-circuit" this local
expressions?

Also, what is your metric to measure a community diversity? I don't want to
be pessimist, nor to look like I blame the current wikidata community, but
it doesn't seems evident to me that it currently represent human diversity.
I think that there are probably a lot of economical/social/educational/etc
barriers that may seems like nothing to anyone already involved in the
wikidata community, but which are gigantic for those
non-part-of-the-community people.

Now to give my own opinion of the representation/ontology you are building,
I would say that it's based on exactly the opposite premisses I would use.
Wikidata Q1 is universe, then you have earth, life, death and human, and it
seems to me that the ontology you are building have the same
anthropocentrist bias of the universe. To my mind, should I peak a central
concept to begin with, I would not take universe, but perception, because
perceptions are what is given to you before you even have a concept for it.
Even within solipsism you can't deny perceptions (at least as long as the
solipcist pretend to exist, but if she doesn't, who care about the opinion
of a non-existing person :P). Well I wouldn't want to flood this list with
epistemological concerns, but it just to say that even for a someone like me
that you may probably categorise as western-minded, this "ontology" looks
like the opposite of my personal opinion on the matter. I don't say that I
am right and the rest of the community is wrong. I say that I doubt that you
can build an ontology which would fit every cultural represantions into a
tree of concepts. But maybe it's not your goal in the first place, so you
may explain me what is your goal then.

[1] I use quotes because it's seems to me that what most IT people call an
ontology, is what I would call a representation.


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Dipl. Inf. Sebastian Hellmann
Department of Computer Science, University of Leipzig
Events: NLP & DBpedia 2013 (http://nlp-dbpedia2013.blogs.aksw.org, Deadline: *July 8th*)
Venha para a Alemanha como PhD: http://bis.informatik.uni-leipzig.de/csf
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Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
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