TITLE: Weird integral symbol : $\mathrel{\int\!\!\!\!\!-}$
QUESTION [8 upvotes]: What does this integral sign mean ($\int$ with line going through the middle)?
$$
\mathrel{\int\!\!\!\!\!\!-}
$$
(It had something to do with the Beckenbach-Radó Theorem)

REPLY [4 votes]: Also used for the Cauchy Principal Value of an integral.