# Einstein equation's RHS sign

1. Sep 10, 2011

### TrickyDicky

Fast question :I noticed that often the EFE are presented without the minus sign in the source term, (G=kT instead of G=-kT) does that have some reason behind or is it just plain sloppiness?

2. Sep 10, 2011

### robphy

3. Sep 10, 2011

### sweet springs

Hi, TrickyDicky.

There are two ways of contraction defined in getting Ricci tensor from Rieman curvature tensor, i.e. contraction of first two indexes and contraction of the first and last indexes. Since Rieman tensor is antisymmetric, two ways are different only in sign.

Regards.

4. Sep 10, 2011

### TrickyDicky

Ok, thanks.

5. Sep 10, 2011

### yenchin

http://equatorfreq.wordpress.com/2010/08/13/signs-in-einsteins-equation/" [Broken] is a more detailed explanation. I really find all these different conventions confusing.

Last edited by a moderator: May 5, 2017