1. Aug 27, 2010

### archipatelin

Do know anybody explicit form of variation action quadratic in Riemann tensors (for general dimension)?
Or computer program for symbolic and tensors algebra, which the variation tell me (preferably open-source)?

Thx

2. Aug 27, 2010

$$R_{\mu\nu}=\partial_\mu \Gamma_{\nu}-\partial_\nu \Gamma_{\mu}-[\Gamma_\mu,\Gamma_\nu]$$
Then apply the variation $$\delta$$. Use the Leibniz rule.