# How do I interpret this summation-integral notation?

Reading a paper I came across this abomination of a notation, my question is, how do I interpret it?

For context I'll post the whole page + the notation as a separate.

The notation in mind is this weird summation-integral from P to B

How am I supposed to read that?

• @user190081 That should be an answer – David Z Sep 11 '18 at 22:30
• May I ask what equation B1 is as it seems to be the definition of the integral, just curious as why that wasn't mention in the original post – Triatticus Sep 12 '18 at 5:49