I recently came across an equation that I do not understand, and I need help to interpret it. I believe that the equation deals with Calculus due to the symbols used; however, I put it in this section because I am not sure. Any help on deciphering it, such as the name of the equation, what the symbols within it represent, or even the names of the symbols used, is appreciated. The attached file and link below both lead to a picture of the equation (it was taken from a photo, so I could not copy-paste it).

http://i.imgur.com/q8u5G.png