Lie derivative

cosmos 9th November 2017 at 1:56pm
Differential geometry

Suppose ϕt\phi_t is a (locally defined) One-parameter group of diffeomorphisms defined by vector field XX. Then there is a naturally defined Lie derivative

LXα=tϕtαt=0\mathcal{L}_X \alpha = \frac{\partial}{\partial t} \phi_t^* \alpha |_{t=0}

of a p-form α\alpha by XX. It is again a pp-form.

See here

The Lie derivative for Vector fields is the Lie bracket.

Cartan's formula

A formula for the Lie derivative of a k-form using the Exterior derivative and Interior product


Intuition

As explained in Lie bracket, "So it says in which direction would I need to change the geometric thing α\alpha at each point, so that the flow ϕt\phi_t induced by XX takes it to the original α\alpha" (but this is not totally correct as can't generally define pushworfard, only Pullback)