# Interpreting a vector expression

1. Feb 18, 2010

### wofsy

In R^3 I have two vectors a and b and the operator D = (d/dx,d/dy,d/dz)

What is the interpretation/ picture of (aD)b - (bD)a? This is another vector.

Last edited: Feb 19, 2010
2. Feb 19, 2010

### Ben Niehoff

You mean a geometrical interpretation? It's the Lie derivative, ${\mathcal L}_A B$.

3. Feb 19, 2010

### wofsy

thanks. That's all I need.