I would like to print the partial derivative operator $\frac{\partial}{\partial k_x}$
, but the spacing and the length of the bar bug me a little. I would really like the fraction to be typeset as $\frac{\partial}{\partial k}$
(which has a shorter bar and the upper $\partial$
further to the left), with the subscript ${}_x$
added afterwards.
I'm definitely sure this is possible. What would be the quickest, cleanest way?