TITLE: Mathematical notation for choosing an element randomly from a set?
QUESTION [6 upvotes]: I have a nonempty set $\mathcal{S}$ with finite number of elements. Is there any mathematical notation to randomly choose an element $x$ from the set $\mathcal{S}$ ? 
Each element in the set $\mathcal{S}$ has got equal probability (uniform probability) for getting chosen.

REPLY [2 votes]: $x \in_R S$ is a common way to denote that $x$ is chosen randomly from the set $S$. See, for example, this question.