[WikiEN-l] Types of categories

[Roger Luethi]

On Sun, 04 Jun 2006 11:31:02 -0400, Anthony DiPierro wrote:
> > That's why nobody made it, but not why it shouldn't be done.
> >
> I'd say it's both.  There shouldn't be categories with only one
> article in them.  IMO that's just common sense.

Yes, for all (current) practical purposes. My point was that there are
other reasons that should stop people from creating such categories whether
or not there is more than one article in it.

> compute category intersections.  But the software doesn't do this, so
> people make do with what they've got.

Right. When making suggestions, we need to be careful to indicate whether
we propose a work-around for broken software or if we are talking about
an ideal solution, or something in between. Plus the problem we are trying
to solve. I know I failed already in this short thread :-).

> Once the software is written to compute intersections of categories
> within the Mediawiki software, it would be relatively simple to
> recategorize the articles into their parent categories, such that no
> information was lost.  The way this would be done is that all articles
> in a subcategory which had multiple parent attribute categories would
> be automatically moved into the parent categories.  This would be
> repeated until no such situations continued to exist.  The ad-hoc
> structure could still be kept, but it could be calculated on the fly
> (along with new types of intersections which could be easily added).

So instead of in the category "Bridges in France", the "Pont du Gard" would 
now be in the categories "Bridges" and "France"!?

> (Now that I do this on an example, I see that this algorithm would
> probably have to be tweaked to deal with subcatgories of
> [[Category:Categories by topic]], but that's not too bad.)

I suspect there are more corner cases than we imagine.

> > For instance, how do you connect the districts of Paris to the category
> > Paris? What is a subset of the parent attribute "Paris": "Districts of
> > Paris", or "Quartier Latin", or neither? Does it bother you if the article
> > on a French district is now in a subcategory of "Capitals in Europe"?
> >
> [[Category:Paris]] is a theme, not an attribute, so [[Category:Paris]]
> should not be a subcategory of [[Category:Capitals in Europe]].

One problem I'm seeing here is that your proposal focuses on one single
type of hierarchies. Paris, France, Europe are now all themes. So if I
ask for an intersection of categories "Bridges" and "France", the results
include bridges that for any reason are related to the "France" theme.
There is no way to ask for Bridges in France, or Paris.

One solution would be to create "is part of" or "is in" categories in
addition to the "is a" categories. Then you can have a hierarchy with "Pont
du Gard" -> "France" -> "Europe", or "cylinder" -> "engine" -> "car".

We'd have two indepent types of categories, plus a third, the catch-all
"theme".

> > female human beings and your example [[Category:Feminine hygiene]]? How
> > about [[Category:Women's rights]]? Add an umbrella cat "Somehow related to
> > women" maybe?
> 
> [[Category:Women]] could be a subcategory of [[Category:Woman]].

Heh. Looking at [[Category:Women]], it's now a subcat of both
[[Category:People]] and [[Category:Humans]].

> mistakes all over again.  The advantage of my proposal to not allow
> themes as subcategories of attributes is that it can be implemented
> today, without much disruption, and without modifying any code.

What I missed in your proposal is how you retain existing theme
information. Duplicate categories in a theme namespace?

Roger