In a paper I am reading, I have come across the following formula:
$\int_\omega f\, \partial \Omega$
in which $\Omega$ is a bounded region in $\mathbb{R}^n$, $f:\Omega \to \mathbb{R}$ a function, and $\omega \subset \Omega$.
What is the meaning of $\partial \Omega$ in the integral? Is this standard notation?
EDIT:
I am not actually so much interested in the concrete problem in which the above formula occurs. I just did not understand the use of the "curvy delta" symbol in the integrand, and presumed it would be some kind of standard notation I did not know. FWIW, here is a link to the paper, the formula in question is number (4) on page 268.