When I was learning Pixar's Renderman for my student film Delivery, during my research I learned about analytic lights and how they effect render times. I am not a lighting artist but its still very good to know how Renderman calculates lights especially if you have a special case that is uses lighting differently.
The primary mode of lights in renderman are called analytic lights because they are economical to render time. They are highly mathematical modeled lights, highly efficient, and they use aerial lights. Thus they are calculated cleaner and give us a faster result.
Analytic lights include: