Hi, I'm DexDor (Dex for short) - (amongst other things) a male Wikipedia editor.

In Wikipedia I mainly wikignome - in particular to improve categorization of articles and making related changes (e.g. fixing WP:REFERS, splitting articles that are on more than one subject, adding links to Wiktionary/Commons etc).

This user is a Cantabrigian. This user enjoys bicycling.

This user lives in the United Kingdom. This user is a Pastafarian.

• User:DexDor/Categories
• User:DexDor/Dabs and SIAs

Category intersection can be used to detect categories that are at an anomalous position in the category structure - e.g. below both Category:Articles and Category:Help (a page can't be both encyclopedic content and a help page so there should be no categories for such pages). I chose 12 high level categories (Articles, Books, Dabs, Essays, Files, Help, Inactive pages, Portals, Redirects, Templates, Users and WikiProjects) - those categories with a letter in brackets shown in the diagram below.

Other categories directly below Category:Contents (as of July 2016) are Category:Wikipedia categories‎, Category:Featured content, Category:Glossaries, Category:Image galleries, Category:Indexes of topics, Category:Lists‎, Category:Outlines, Category:Timelines‎.

There are 66 combinations of any 2 of these 12 categories (Article+Book, Article+Dab, Book+Dab, ...) -

• 3 of the 66 are (I believe) valid combinations - Template+Wikiproject, User+Wikiproject, Essay+Wikiproject.
• 37 of the 66 are empty (when last checked, down to depth 6).^[1]
• Categories that are under both Category:Wikipedia redirects and another high level category (Category:Wikipedia templates, Category:Wikipedians, Category:WikiProjects) - these need further analysis/discussion/cleanup. Note: There are both pages in the category namespace that are redirects (e.g. Category:Wikipedians who like Puella Magi Madoka Magica) and category pages intended to contain redirects (example?).
• Other combinations of Articles and another high level category for pages for readers - AB. E.g. Category:Wikipedia books on the United Kingdom. One problem here is that a "Wikipedia books on foo" category can include pages in User namespace which is an exception to the normal rule that user pages are not categorized as articles - that exception could make it more difficult to detect incorrectly categorized user pages. One solution would be to create categories such as "Category:Wikipedia community books on the United Kingdom" (see Category:Wikipedia books (community books)) and not allow other book categories to be in article categories - however, this would be a significant change from existing categorization. Another solution would be to have a rule that only community books (i.e. in Wikipedia namespace) can be placed in topic-based books categories - e.g. in Help:Books#Saving_and_sharing_your_book_with_others (which really needs to say something about categorization).
• Other combinations of Articles and another high level category - AD, AF, AH, AP, AT, AW.
• The remainder are FI,HE, HF, IP, IT, IU, IW, PF, TF, TH, UH, WH, TP, WP, UT, FW - these need further analysis/discussion/cleanup.

I'm also using category intersection to detect individual pages that are mis-categorized (e.g. talk pages under Category:Articles), but it many cases it's necessary to sort out anomalies in the category structure first.

• Federal Law on Cultural Valuables Displaced to the USSR as a Result of the Second World War and Located on the Territory of the Russian Federation (long article title)

• Example of (presumably) badly translated stuff: "shipyard coat 57 tons of laughs of mundaca" (Mundaka wave as of 5 Sept 2013).