Derivation of Komar formulae from ADM formalism? Is there a way to derive the Komar formulae from the ADM formulae? Both the formulae give the same answer for mass and angular momentum, so I was wondering if one can be derived from another. 
On an unrelated note, if I know all the killing vectors, can I use it to uniquely determine the metric?
 A: The Komar and ADM formulae apply to different classes of spacetime. In particular, the ADM formulae apply only asymptotically flat spacetimes whereas the Komar formulae apply to any spacetime with Killing vectors. Moreover, the ADM formulae can only be applied to a sphere at "infinity", while the Komar integrals can be integrated over any surface.
There are, of course, spacetimes, such as Schwarzschild and Kerr, that are both asymptotically flat and have Killing vectors. In these cases both give the same answer. However, there are also spacetimes that have Killing vectors that are not asymptotically flat, and the other way around. Consequently, one would not necessarily expect to be able to derive one from the other.
In particular, I see no way that the Komar integrals could be derived from the ADM ones. The other way around, I believe you can obtain the ADM integrals by using the fact that asymptotic flatness implies that the spacetime has asymptotic Killing fields. (Actually, I'm not so sure about the last part)
