[WikiEN-l] Types of categories

[Roger Luethi]

On Sun, 04 Jun 2006 18:07:15 +0200, Steve Bennett wrote:
> > Okay, that's equivalent to Steve's Amelie-Paris relation. I agree that's a
> > problem.
> 
> The problem there, now that I think about it, is that Paris should not
> be in the category "Paris" (as was pointed out by someone else).

Yeah, although it's a very common thing to do. The alternative is to write
"See also: [[Category:Paris]]" in the Paris article, which is harder to
find (especially if there are many external links or references). That's
a very practical reason, though.

> Amelie should be in the category "Paris"

If Amelie goes into that category, then the category means "related to
Paris" and becomes almost meaningless. Do we add every movie that's got an
Eiffel Tower in it? Every article on people who were born there, died
there, or lived there? Even if the category remained small, how is such a
vague piece of information useful? ... It seems that Amelie should be in
"Films set in Paris" (or something like that), and that category should be
in the category "Paris".

> The article Paris should be in the category "European capitals" (say)
> The article Paris should not be in the category "Paris"
> The category "Paris" should not be in the category "European capitals".
> 
> Actually, even simply obeying this last rule would solve it: Paris
> *the article* belongs in the taxonomic category (Paris *is a* European
> capital) , but "Paris" the category is thematic, so should only belong
> to thematic categories: maybe "Europe" in this case.
> 
> That actually seems to fix the problem. I saw this with The Beatles
> for example. John Lennon was in category "The Beatles" (thematic), and
> that category was in "British rock bands" (taxonomic), leading to the
> conclusion that Lennon was a British rock band.

It's mostly scripts that get confused. I suspect most normal users won't be
confused but find that convenient.

Say I navigated down to "British rock bands" (taxonomic), discover The
Beatles and would like to see what WP has got on them. With the proposed
system, I need to open the article, scroll down to the bottom -- nope, if
there is a category for them, the article can't be in it, so scroll back up
several pages worth of navigation boxes, external links, and references to
spot the "See also" section which hopefully contains a link to the category
"The Beatles" if there is one.

I'm not sure we can convince people that it's a win overall.

> > But even if we maintained a complete and up-to-date system of subcats, we'd
> > still make it hard for people to find articles using categories. For some
> > fairly sensible reasons, the rule is to include articles only to the
> 
> I have never completely understood these "sensible reasons". It's
> redundant from a taxonomic point of view, but since category
> navigation works so badly (there is no way to easily see everything in
> a category and all its subcats), it often seems to work well from a

It's a trade-off. The sensible reason is that while your argument is
correct, a category that contains hundreds of entries is equally unusable.

> It's ok if a category consists entirely of subcategories, but if there
> are both articles and subcats in it, then not having an article in the
> category by virtue of the fact that it's included in a subcat is
> awkward and doesn't work well.

The higher category often serves as a waiting room for articles that have
not been sorted into a subcat or make for a tiny subcat only (several
subcats [[Category:Astronauts by nationality]] contain only one or two
articles).

> Hmm, the difficulty is deciding what "subcategory" really means. I
> assume you're getting at the fact that a taxonomic subcategory should
> simply be getting more specific, and leading to more specialised
> subjects (so "Capitals of Europe" might have subcat "Capitals of
> Western Europe" or "Capitals of the European Union"), maintaining the
> "X is a Capital of Europe" mantra.
> 
> In this case, it would seem best that "Districts of Paris" was a
> category of the thematic category "Paris".

(I know it doesn't work too well with this example, but bear with me) And
"Districts of Paris", being an attribute, is also in (taxonomic) "Districts
of European Capitals" which in turn is in (thematic) category "Europe",
right?

> > Or going back to [[Category:Women]]: You could declare that only articles
> > on instances of women (i.e.  biographies) can ever be under that category,
> > and that only sets of such articles can ever be subcategories of the
> > category women. -- You could even create a separate [[Category:Woman]],
> 
> This is a perfect example of a problem aluded to in the MoS on
> categories: Women is both a taxonomic category (it's a plural) and a
> theme (eg, Women throughout the ages, or whatever). Disaster is
> inevitable from that point onward.

We can fix that.

> The taxonomic category "Women" could be split immediately into
> fictional women and real women, then into living and dead women, then
> again by various means.

So "living women" is taxonomy, but "Living persons" is an attribute?

One obvious problem here is that you don't have the strict hierarchy that
you proposed in your initial posting. For Bridges and France, there are
natural hierarchies of higher or more generic concepts. The relations
between France and Europe or between bridge and structure are directed.
Women, living, and fictional have no directed relations. You could use them
in any order.

And another thing I just noticed: The taxonomy in Category:Bridges breaks
down after only one level, category [[Category:Buildings and structures]]
which is a subcategory of four themes and nothing else. [[Category:Nobel
Peace Prize winners]], one of your examples for an attribute, on the other
hand, contains a stack of "Nobel laureates", "Prize winners", "People".

Your definitions of taxonomies and attributes need work :-).

> > subcategories like "female reproductive organs" containing articles like
> > uterus. -- But how would you express the undisputed relationship between
> > female human beings and your example [[Category:Feminine hygiene]]? How
> > about [[Category:Women's rights]]? Add an umbrella cat "Somehow related to
> > women" maybe?
> 
> With a separate, thematic, category. What would you call it? I don't
> know. In practice, this would probably only work through a whole
> separate structure, leaving Categories only for taxonmic categories
> ("X is a Y"), and creating a structure called Subjects or Themes or
> something.

Distinct namespaces for different types of categories. It would involve
some coding and the migration must be planned, but it might be easier to
explain and easier to maintain. It would also be another small step towards
a semantic web.

Roger