# Calculating lie derivative

## Homework Statement

Calculate the lie derivative of the metric tensor, given the metric,

$g_{ab}=diag(-(1-\frac{2M}{r}),1-\frac{2M}{r},r^2,R^2sin^2\theta)$

and coordinates (t,r,theta,phi)

given the vector

$E^i=\delta^t_0$

## Homework Equations

$(L_Eg)ab=E^cd_cg_{ab}+g_{cb}d_aE^c+g_{ac}d_bE^c$

## The Attempt at a Solution

$(L_Eg)ab=E^cd_cg_{ab}+g_{cb}d_aE^c+g_{ac}d_bE^c$

all derivatives above being partial

Now the Last two terms go to zero, since E^i=Kronecker delta=constant and so its derivative is zero.

So,
$(L_Eg)ab=E^cd_cg_{ab}$

$(L_Eg)ab=\delta^t_0 d_cg_{ab}$

I'm unsure how to take it from here.

Firstly, I'm unsure what
$\delta^t_0$

means. Does it means we get the result 1 at t=0 and zero for all other times?

How does it then affect the equation below.

$(L_Eg)ab=\delta^t_0 d_cg_{ab}$

Last edited:

I think what they meant to write is $E^i=\delta^i_0$ i.e. the vector field with a constant value 1 in the time component. So the Lie derivative is pretty trivial.