PlanetMath is a virtual community which aims to help make mathematical knowledge more accessible. PlanetMath's content is created collaboratively: the main feature is the mathematics encyclopedia with entries written and reviewed by members. The entries are contributed under the terms of the GNU Free Documentation License (FDL) in order to preserve the rights of both the authors and readers in a sensible way.
PlanetMath entries are written in LaTeX, the lingua franca of the worldwide mathematics community. All of the entries are automatically crossreferenced with each other, and the entire corpus is kept updated in realtime.
In addition to the mathematics encyclopedia, there are books, expositions, papers, and forums. You also might want to check out encyclopedia requests if you'd like to see something we don't have. We also have the encyclopedia available in offlinebrowsable snapshot form, and in book form. Also see PlanetMathexclusive feature articles and topics.
Top starting points: PlanetMath Overview  High School Mathematics  Calculus  Statistics  Real Numbers  (more)
Accounts are free and required to do anything other than browse, so sign up! It only takes a minute. For more information, see the FAQ, other documentation, PlanetMath mailing lists and other public fora, or ``the PlanetMath thesis''.
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