If $n(x)$ is the standard normal density on $R^2$ and if $A = -A$ and $B = -B$ are convex subsets of $R^2$ then $$\int_{A\cap B}\mathbf{n}(x) d^2x \geqq (\int_A \mathbf{n}(x) d^2x)(\int_B \mathbf{n}(x) d^2x).$$
@article{1176995808,
author = {Pitt, Loren D.},
title = {A Gaussian Correlation Inequality for Symmetric Convex Sets},
journal = {Ann. Probab.},
volume = {5},
number = {6},
year = {1977},
pages = { 470-474},
language = {en},
url = {http://dml.mathdoc.fr/item/1176995808}
}
Pitt, Loren D. A Gaussian Correlation Inequality for Symmetric Convex Sets. Ann. Probab., Tome 5 (1977) no. 6, pp. 470-474. http://gdmltest.u-ga.fr/item/1176995808/