- #1

- 326

- 6

## Main Question or Discussion Point

hi, when I see the einstein hilbert action I really started to be curious about that equation $$S=\int{\sqrt{g}d^4xR}$$. How is this action derived?? Is there a any proof using action integral involving the lagrangian density ??? If there is not a derivation from lagrangian action, What is the real proof of it ?? I am looking forward to your responses. Thanks in advance....