$\varphi_t$ is a one-parameter group of diffeomorphisms generated by a vector field $V$ on $M$,
$$ g_{ij}=\varphi_t^*g_{ij}(x,0) ~~~ \frac{\partial g_{ij}}{\partial t}=-2R_{ij} $$
How to show that $-2Ric=\mathcal{L}_vg$ ? The $\mathcal{L}_vg$ is Lie derivative
I only have a little knowledge of Riemannian geometry and PDE.But I must read some paper about Ricci flow .What should do? What book I should read before read Ricci flow? Thanks for any helping .