Worldsheet velocities
In particular, we have a natural basis .

Let us decompose using this basis:

(12)

Here denotes (for now...) the -component. On the right hand side, the first line contains the -component, and the second line the non-vertical components.

Again, it makes sense to ask what is . I have shown my paper (in a rather roundabout manner) that is the matter part of the worldsheet field from the action (10), which is related to the charge density of the BRST transformation :