GRwiki is a repository of basic definitions and formulas for gravitational physics. It is meant to serve as a high-level tool for active GR researchers, not a place to learn the theory. This site began as a transcription of handwritten notes, including definitions and derivations, that I collected over the years and kept in a file drawer. These notes have been an indispensable resource for my research. If I ever needed the definition of the Lie derivative of a weight -2 covariant vector density, I knew where I could find it. The problem with a file drawer full of notes is that it's not very portable. I wanted to have access to these results from my office, home, and on the road. Hence this wiki was born.
Please use this site with care. My goal is to create a site with as few errors as possible, but there are no guarantees. You should not trust any result posted on GRwiki unless you have verified it for yourself.
You are also welcome to contribute to GRwiki. Please give careful thought to any additions or changes you might wish to make. Currently any registered user is allowed to edit GRwiki pages.
Attention! I have recently upgraded the GRwiki hardware as well as the web server, database, and wiki software. The primary motivation for the software upgrade was to make GRwiki more resistant to spambots. As before, everyone is free to view the contents of GRwiki, and only registered users can edit pages. What is new is that registration now requires the user to pass a simple Math Captcha quiz. To keep the transition as simple as possible, I did not attempt to transfer the database of users from the old system to the new. Therefore, if you were a registered user before, you will have to register again. (David Brown, August 6, 2011)