On 6/4/06, Matt Brown <morven(a)gmail.com> wrote: What you're saying makes sense, but does not currently have consensus. Implementing it therefore sounds like a bad idea bound to cause upset. Steve

On 6/3/06, Steve Bennett <stevagewp(a)gmail.com> wrote: I suspect that simply no real discussion of this has taken place yet. -Matt

On Sat, 03 Jun 2006 17:27:59 -0400, Anthony DiPierro wrote: Okay, that's equivalent to Steve's Amelie-Paris relation. I agree that's a problem. That's why nobody made it, but not why it shouldn't be done. It would be nigh impossible to do well because once we start combining attributes to create new categories, we are looking at maintaining links between articles and an exploding number of subcategories. 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 subcategory, but not to the parent. There is no way to list articles based on a subset of criteria (the articles in subcategories are effectively hidden on separate pages which is only helpful if you know which one to pick). You are right, we can't effectively build these intersection categories on the fly at the moment, but we _could_ automatically create or update such intersection categories if the categories weren't the mess that Steve and you describe. Kind of like the search index. The devil is in the details. 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"? 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]], 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? Roger

On Sun, 04 Jun 2006 11:31:02 -0400, Anthony DiPierro wrote: 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. 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 :-). So instead of in the category "Bridges in France", the "Pont du Gard" would now be in the categories "Bridges" and "France"!? I suspect there are more corner cases than we imagine. 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". Heh. Looking at [[Category:Women]], it's now a subcat of both [[Category:People]] and [[Category:Humans]]. What I missed in your proposal is how you retain existing theme information. Duplicate categories in a theme namespace? Roger

Anthony DiPierro wrote: [[Category:Klingons]] could be another sub-category. :-) It's taxonomic among zoölogists. Not in the general case, but there are still places where it can be useful. "Science" could be about science generally; "sciences" would list the various branches." Reorganization can keep happening, but not on any massive scale. Ec

Anthony DiPierro wrote: They should be avoided, but I would not proscribe them. If you are sub-categorizing mammals you still need to deal with the ones that are so different (like the platypus) that they will end up in a one article category. Exactly Is it practical to have people debating whether something is a theme or an attribute? Avoid distinctions that will have to be re-explained every time another newbie joins. One can work towards this, but any enforcement is a bit like passing a law that requires everybody to think logically. Ec

On 6/8/06, Anthony DiPierro <wikilegal(a)inbox.org> wrote: Any system that requires logic and thought to operate well, but can be operated by anyone, is likely to live in a state of semi-functioning. The people who are good at categorising will be overworked, and thus there will be parts of the system that will live for days, weeks, or months, badly categorised. There's nothing particularly wrong with that. Steve

On 6/4/06, Roger Luethi <collector(a)hellgate.ch> wrote: 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). Amelie 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. 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 practical perspective, so that the item actually shows up where you expect it to. 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. Yep. 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". 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. 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. The thematic category "Women" could be broken into feminism, biology, etc etc. 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. Steve

On Mon, 05 Jun 2006 00:01:26 +0300, Ilmari Karonen wrote: Heh. Valid point, and it seems that many editors would agree with you. [[Category:Subdivisions by country]] does something like that. Now _that_ is fortunately a minor problem. Call one of them "sheep (thematic)" or something. It's not like namespace collisions are unheard of in WP. Roger

On Sun, 04 Jun 2006 18:07:15 +0200, Steve Bennett wrote: 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. 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". 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. 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. 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). (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? We can fix that. 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 :-). 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

On 6/5/06, Anthony DiPierro &lt;wikilegal(a)inbox.org&gt; wrote: That's probably not bad. The page would have a basic structure like: Description Related categories <-- new Subcategories Articles in this category People *want* to put "related categories", but they break the category system if they make them subcats. We need to channel that desire. Steve

On Mon, 05 Jun 2006 11:43:30 +0200, Steve Bennett wrote: First we need to find out which rules make sense and then make a convincing case: Demonstrate the benefits, have answers to apparent drawbacks, a realistic migration path. Compare the problems solved to the problems left. If we ever got that far, there should be a sandbox that challenges people to add problem and corner cases. New rules have little credibility unless you can demonstrate that you don't have to rethink parts of your system every time a new example comes up. Unfortunately, I'm not aware of a good method for presenting and editing the kind of graphs we're talking about in a wiki. Ah, here I agree. So we have attributes for state (dead/alive). You probably want them for location, too. Being able to slap "in France" on an article would be helpful. Problem is, not everything is a bridge where "in <location>" has an unambiguous meaning in relation to the subject of the article. An American movie may be "set in France", or a movie set in the US may be "shot in France". And people may be "born in France" or have "died in France". I guess the reason I am only mildly interested in hierarchies is that many interesting attributes (dead/alive, colors, professions) don't fit well into hierarchies. I think the real power comes from combining attributes. The German WP is much closer to that. For instance, they don't have categories like "Polish Chemists". They only have the attribute categories "Polish" and "Chemist". From a practical point of view, that's less usable than what we have (they basically need to use CatScan which is fairly limited, and casual users don't know about it anyway). But it's conceptually cleaner, and they are in a better position for making interesting experiments. Combining rigid rules with common sense is hard. I am tempted to quote your line about inevitable disaster. Your first question answers the third :-). As for the second, I don't think implementation details matter much at this stage. Roger

On Tue, 06 Jun 2006 13:51:33 +0200, Steve Bennett wrote: Right. But more importantly, the way categories are used is thorougly entrenched and I suspect your chances to change it are close to zero even assuming you could make it a policy. It would be easier to create clean trees in a parallel namespace. Say, leave [[Category:Bridges]] alone and create [[is a:Bridge]] (or, without software changes, [[Category:is a Bridge]]). That said, it seems that you are overestimating the importance of one type of relationships at the expense of others. Some hierarchies are perfectly natural and useful but are not "is a" relationships (Europe - France - Paris, Family - Genus - Species). Many attributes are perfectly natural and useful but they tend not to fit hierarchies well. You starting using them as soon as you sketched out the supposedly taxonomic category women. There simply is no natural taxonomic hierarchy for women, just a bunch of attributes. Now _if_ you want to draw a natural hierarchy with women in it, try genealogy. But guess what? That's another type of relationship that we can't deal with (X is ancester of Y, Y is ancestor of Z). Not without supporting evidence :-). Yes. The example Anthony posted today in another thread was useful: ---------------------------- snip ---------------------- Coastal_construction *Ports_and_harbours **Port_cities ***Edinburgh ****Education_in_Edinburgh [...] ---------------------------- snip ---------------------- Agreed. But the long-term goal should be for "Made in US" to be dynamically generated. It's just a bunch of relationships ("made in", "died in") and a list of attributes -- hierarchical even, in this case ("New York", "US", "North America"). You can have all kinds of fun with that, until someone adds a relationship like "was named after" and your software concludes that if people named after London are also named after Great Britain :-). But you have to deal with them anyway. Your suggested something like this: women *real women *-living women *-dead women *fictional women You _are_ using attributes here. So what if I'm looking for the biography of a female Polish chemist but don't know whether that woman is still alive? Do I have to check both categories, or do we maitain trees for every possible order of attributes (which is pretty much what we are doing right now, manually)? Where's {{Category:Polish chemists}} coming from? Defined on a separate page? And do we also add {{Category:Female chemists}} and {{Category:Polish physicists}} and {{Category:Polish women}} to the same article? Roger

On Tue, 06 Jun 2006 21:06:57 +0200, Steve Bennett wrote: Yes, something to keep in mind. Finding a better system is not trivial, but it is the easiest part. Not as far as I can tell. It would only distinguish relation types. Plus it's a hack. With the current software, that could be implemented as: [[Paris]] [[Category:is a city]] [[Category:is a (is there a name for "city or town or village or some other place"?)]] [[Category:in France]] (or [[Category:located in France]]) [[Category:in Europe]] Okay. What i see is (I added more information for illustration): [[Britney Spears]] [[Category:is a singer]] [[Category:is an entertainer]] [[Category:is a person]] [[Category:is a child actor]] [[Category:is an entertainer]] [[Category:is a person]] [[Category:is alive]] [[Category:is female]] [[Category:born 1981]] [[Category:born in McComb, Mississippi]] (that kind of category would be hard to maintain manually) [[Category:born in Mississippi]] [[Category:born in the United States]] Here are some other fun (existing!) categories from said article: Worst Actress Razzie: "won a Worst Actress Razzi" Soubrettes: "is a soubrette", I guess!? American child actors: ...? "is a child actor" or "was a child actor?" Hollywood Walk of Fame: Ugh. High school dropouts: Ahm? [[Pont du Gard]] [[Category:is an aqueduct]] [[Category:is a bridge]] [[Category:is a construction]] [[Category:in France]] [[Category:built by Romans]] (?) Agreed. Examples? It is. But "species" is not a genus. Like city is not a country. I see two major problems with the status quo: * multi-concept categories (American child actors) force us to maintain a complex system of subcategories (but they paper over shortcoming in the software). The German WP shows it doesn't have to be this way, but it might be difficult to convince people on WP:en until Mediawiki can create intersections * categories with unclear relations that are used for everything We can fix both problems without changes to the software (but it still comes at a cost). However, we are dangerously close to inventing a poor man's version of a semantic wiki. My impression is that the German WP is pretty close to that. But categories are also an important navigation aid, and that's where WP:de falls short. Yup. Number of countries: > 200 Occupations: hundreds Not every country has people in every occupation, but these are just two attributes. That's many times 2 minutes. We should not have to do this manually. _Or_ editors could simply add all the attributes and forget about the template. Attributes on [[de:Marie Curie]] (I'm not making this up): woman chemist physicist polish (+ some more) I guess splitting woman into person and female seemed too awkward to the Germans. Wimps. Roger

On 6/6/06, Roger Luethi &lt;collector(a)hellgate.ch&gt; wrote: Why do I get the feeling the current structure probably already looks a lot like that, but with different names? Good, good - why is that cat hard to maintain manually? Yes. The fact taht these are hard to express clearly is very telling. Dropped out of high school? Yep, why not. (Built by Ancient Romans if you prefer...) Erm, I mean, people will probably end up being "casual" with attributes...but if we could make the taxonomic classificatins a bit more firm...not sure what I'm getting at (it's late). Yes, but I'm not sure what you're point is - are you talking about "species" the article? Of course it shouldn't belong to "genus" the category...probably missing something. Yay, how hard can it be? Like [[Category:Lasers]]? ;) Would a fully fledged semantic wiki ever work on Wikipedia scale? Trust the Germans to be organised! Obviously the shortcoming is the lack of intersections though. You know, what would be really awesome would be seeing at the bottom of each article: Categories: Bridges, in France, built by Romans See other: Bridges in France (200 articles), Bridges built by Romans (137 articles), Bridges in France built by Romans (15 articles). Is that feasible? Ok, I think we got sidetracked. I was saying you could put the relevant attributes directly on a page, and manually search for the appropriate intersection. However, people could also create templates, or links to predefined groupings of attributes, if they find them interesting and relevant. (Note that this would allow people to create "Jewish mass murderers" categories easily :)) Ok, you did understand, I was just unclear. Heh, what do they do for young girls? Steve

On 6/7/06, Roger Luethi &lt;collector(a)hellgate.ch&gt; wrote: Maybe the way to go is have only attributes, but then make certain attributes themselves belong to thematic categories. Something like: The Outsider +Novel +By Albert Camus +Existentialist Then make a thematic category "Existentialism" into which the constructed (that is, automatically built by an intersection) category "Existentialist novels" is grouped. Not a good example come to think of it. Should we try and work out, what is the basic point of thematic categories? The problem is that the articles in them are related in such different ways, that it would seem much better to have a page that actually explains the links, and fits them in in a way that makes sense: existentialist authors, existentialist works, history of existentialism etc. Even a structured way of displaying items in subcategorys on the page itself would be handy. Just to continue this example, look at [[Category:Existentialism]]. There are subcategorical conceptual articles ("Existential desire"), related conceptual articles (Absurdism), works (Exile and the kingdom), and miscellaneous (Kierkegaard and Nietzsche comparisons). Then there's the subcategory "Existenialists" where we find Sartre and Camus. And even better, a perfect example of a thematic subcategory to a taxonomic category to a thematic category: "Søren Kierkegaard", which mostly contains his works, but also mentions a research centre and the man himself. having a single page that quickly defined the topic, linked to the key articles about the topic, then presented sections "Existentialist authors" that transcluded the relevant category, "Existentialist works" that did the same, and finally ended with "related categories". If we had that, then Wikipedia would be really starting to get somewhere as a structured encyclopaedia, as opposed to simply a massive number of articles on various topics. Hmm, well apart from the Prague bit, it would certainly be cool to be able to hijack a geographical structure that had been built once to create other attributes/categories. You would need something fancy like categorical operators though, which is definitely getting more advanced and complicated. Category:Bridges in France would become: Category: (is a bridge) (in) (place:France). Since (place:Lyon) would be defined once and for all as being a subcategory (subplace?), any bridge in Lyon would automatically be a bridge in France. To solve your example, a different "operator" (born in) would be used, combined with a place. The end result is to replace a number of parallel hierarchies with a single one combined with several different operators: in (place) born in (place) died in (place) famous in (place) ? buried in (place) ? banned in (place) ? One obvious advantage is that people could immediately start assigning articles to categories like "Born in New York" or even "Born in Queens", without losing them from the broader categories "American musicians" etc. That the categories are badly designed and ambiguous. Yep. If the category doesn't tell you exactly what it's about, it must be "random stuff with some tangential connection to X" :) Actually [[Category:Types of lasers]] would be better - "blue laser" is not really "a laser". Very few individual lasers would deserve entries. Hard to see how "laser" would be a good name for a thematic category though. But where else would laser eye surgery or light sabers go? Depends what "on the fly" means. "Each time an attribute is updated" would be one thing. "Each time a user requests" it would be another. The former would fit the mediawiki model a lot better. Clearer groupings, better portals, automatic navigational boxes, more powerful categories (like "German-born Polish scientists buried in France (2 articles)") Redirects solve so many of these problems. Some way where editors can guide the system would be valuable. Some way where power users can ignore the editors' recommendations and see all the possible intersections (ok, within reason) would be nice. We seem to have a couple of different proposals bubbling away, each requiring different amounts of work to implement. I'll see if I can summarise somewhere and synthesise something palatable, to really work out feasibility. And the English Paris article is better than the French one, and the German New York article is better than the English one. Steve

Hi. I know it's been mentioned before, but can I strongly suggest everyone speculating about what how this might work have a look at the Semantic MediaWiki demo here -> http://wiki.ontoworld.org/index.php/Main_Page It needs a lot of work (transitive relations in particular), but it's an interesting start. -- Abi

On 6/6/06, Anthony DiPierro &lt;wikilegal(a)inbox.org&gt; wrote: I'm inclined to think that in practice they pretty much work the same way. However, semantically, I would really like to distinguish concrete, significant, basic categories like "Ships" from much less salient, significant facts like "Born in 1793" or "Winners of Golden Raspberries". However, I suspect that even the most basic taxonomies will have bastard children with two parents: Something could be both a sport and a television show. Someone could be both a musician and a scientist. But maybe the "one taxonomy per article except in strange cases" goal is reasonable? Steve

On 6/6/06, Roger Luethi &lt;collector(a)hellgate.ch&gt; wrote: But at the end of the day, it's a ship. Indisputably so. You would certainly want to put an attribute "shipwrecked" on it, and possible "shipwrecked in 1903" or whatever. Instead of "significant" and "salient" how about "concrete"? The fact that it's a ship is concrete and essential. The fact that it shipwrecked is ancillary. (why do I feel like I'm getting talked into trying to reinvent the field of semantics from scratch) I didn't know she had. Woman. Not many people are going to deny that Halle is a women, or that Titanic was a ship. Halle Berry is primarily an actress. Einstein was primarily a physicist. Ellington was primarily a jazz musician. But I see your point, maybe the taxonomies should stop at "person", and the rest can be attributes. Steve

On 06/06/06, Steve Bennett &lt;stevagewp(a)gmail.com&gt; wrote: But what's our *article* about? It's evenly split between an article on the ship, and an article on the sinking of the ship - if the name of the Titanic herself hadn't entered into common usage, there'd be a good argument for calling the article [[1912 sinking of RMS Titanic]]. (Compare [[Exxon Valdez]] and [[Exxon Valdez oil spill]] - I'm surprised they're not merged) -- - Andrew Gray andrew.gray(a)dunelm.org.uk

On Tue, 06 Jun 2006 07:54:27 -0400, Anthony DiPierro wrote: http://meta.wikimedia.org/wiki/Wikidata Right. You _could_ make it work on some categories, say "Women" or "Nobelprize winners". It cannot possible work for all categories, though, because different languages know different categories. For instance, security and safety is the same word in German: Sicherheit. Thus, [[de:Lifebelt]] is in the German category that is linked to the English category Security. Numbers are much easier to share. Population of a country. Weight of a molecule. I suspect this is impossible. But it's hard to tell if you're not even sure what counts as a taxonomy. Roger

On Tue, 06 Jun 2006 17:36:07 -0400, Anthony DiPierro wrote: These are all possible solutions. However, Sicherheit is not exactly security+safety. It's just much closer than to security alone. I picked that example because it's rather extreme. Here's another one: there are two German words for technology: Technik and Technologie (each has a separate category in the German WP). More importantly, though, many translated words mean almost the same, but not exactly, and some articles will be the corner cases that will make the category in one language but not in the other. You would need a mechanism to exclude categories that won't translate well enough even though an interwiki link exists between them. Opt-in or opt-out, I don't know. 2) is significant if only because the German WP tends to merge subjects into one article, so you have several English articles pointing to the same German one. 3) Extremes are rare, but subtle differences are pretty much inevitable. 6) Different understanding of what categories should exist. Roger

Anthony DiPierro wrote: I think that this would be very difficult across projects, if only because the terminology is different, and there is a cultural element to determining distinctions. To some extent I have dealt with som of this on the English Wiktionary as a byproduct of being all words in all languages, but with English definitions. Category names there would also all be in English. Thus [[Category:Mammals]] could have its usual hierarchical subcategories [[Category:Dogs]], [[Category:Rabbits]], etc. It would also hve [[Category:de:Mammals]], [[Category:ja:Mammals]], etc. which could be developed in a parallel manner for those other languages. To facilitate sorting the language codes would always be lower cased, and the categories themselves would be upper cased. It's best not top get hung up on pedantic distinctions. Ec

Anthony DiPierro wrote: A high level category like people does not need to have direct elements. To be simplistic about it, it would do fine with only two sub-categories, men and women. An element of a sub-category is an element of the superset category. Such a category would be theoretically acceptable but totally impractical. There is an element of art to the design of category hierarchies. A category that's too narrow (like your example) is unfindable; you simply never know which ones exist. At the other extreme, if the category is too broad it becomes more difficult to find things within it. In Wiktionary people have established [[Category:English nouns]] which now has numerous elements, but what user would ever look there to find something? The purpose of categories is to help the passive user to find things. It requires some idea of which Googling strategies work and which don't, and how to modify a strategy which initially doesn't work. Just think of what works when you are searching for something. In my mind a category should not have more than 200 direct elements, this being the number of items that will appear on a single page by default when we ask for a category to be listed. Anything longer should be subdivided. Even so, a person should have the option to have an "include sub-categories" to a determinable level when listing the contents of a higher level category. I suggested something of the sort before categories were implemented, but more from the searching end. The real problem is with the search function, which is remarkably unsophisticated for a project the size of Wikipedia. It's an idea that I have tried to implement for some time at Wiktionary. The difficulty with such hierarchies is that they require people to think logically, and to be able to trace a path back to a single top level hierarchy. Ec