The generalized harmonic formulation can be derived by adding a gauge-fixing term to the Einstein-Hilbert action
Sometimes in a numerical method, you need to be able to continuously turn a calculation on or off in space or time.
Integrability conditions when trying to solve for a conformal factor
Here to save you some algebra and column-inches
An identity between vector commutation coefficients and coframe connection coefficients
These three objects form a superalgebra! Whoa!
When can you integrate-by-parts with Lie derivatives?
Special thanks to Ben Mares for coming up with this identity.
There is a nice 4-dimensional Weyl identity that I can never seem to remember off the top of my head; so I decided I need to write this note so I don’t have ...
The Weyl decomposition, further splitting into E/B, and computing in terms of 3+1 objects
In an effort to keep myself organized, I decided I should type up some notes I have laying around.