Extension:CategoryIntersection

What can this extension do?
This template creates a special page - Special:CategoryIntersection. You put in a list of categories to this page (separated by newlines), and the extension returns the articles that are in all the categories listed. It stores hashes of what categories a page is in in a separate table in db to (I assume) make things efficient. Somewhat akin to the DynamicPageList extensions (but probably much more efficient).

Installation
To install this extension, do the following:
 * 1) add the following to LocalSettings.php:
 * 2) Run the update.php maintenance script
 * 3) Run the refreshLinks.php maintenance script (Warning: This may take a long time if you have a lot of pages on your wiki. If you don't do this step, the extension will only find pages that had their categories added after the extension was installed)
 * 1) Run the refreshLinks.php maintenance script (Warning: This may take a long time if you have a lot of pages on your wiki. If you don't do this step, the extension will only find pages that had their categories added after the extension was installed)