# I understand energy-momentum tensor with contravariant indices, where

1. May 7, 2013

I understand energy-momentum tensor with contravariant indices, where

I think I get $T^{αβ}$, but how do I derive the same result for $T_{αβ}$? Why are the contravariant vectors simply changed to covariant ones, and why does it work in Einstein's equation?

2. May 8, 2013

### Dick

You just lower indices by multiplying both sides of Einstein's equation by the metric tensor, you don't just 'change them'. I'm not sure what you don't understand.