Open problems are classified by Subject, a three level hierarchy in the form Area » Topic » Subtopic. This tree structure can be navigated using the links in the Navigate menu under "Subject".
Open problems are also assigned both Authors and Keywords for reference purposes. Clicking on either "Author Index" or "Keyword Index" in the Navigate menu will bring you to a full list of these terms.
Recent Activity
The Recent Activity menu highlights problems which were recently created or commented on. Clicking the "more" option in this menu brings the user to a display of all open problems sorted in order of most recent activity.


The table display is used when viewing the open problems in an Area or Topic. By default the table is sorted on the basis of Subject, but the reader may sort on the basis of any other field by clicking on the appropriate header.
The teaser display is used when viewing the open problems in a given Subtopic, or those open problems with a given Author or Keyword.