What are categories?
Categories allow articles to be placed in one or more groups, and allow those groups to be further categorized. When an article belongs to a category, it will contain a special link to a page that describes the category. Similarly, when a sub-category belongs to a parent category, it will contain a special link to the parent category’s page. Each category page contains an introduction that can be edited like an article, and an automatically generated list of links to sub-categories and articles that belong to the category. Categories do not form a strict hierarchy or tree of categories, since each article can appear in more than one category, and each category can appear in more than one parent category. This allows multiple categorization schemes to co-exist simultaneously. It is possible to construct loops in the category space, but this is discouraged.
