What does $\ll$ mean? I saw two less than signs on this Wikipedia article and I was wonder what they meant mathematically.
http://en.wikipedia.org/wiki/German_tank_problem
EDIT: It looks like this can use TeX commands. So I think this is the symbol: $\ll$

Perhaps not its original intention, but we (my collaborators and former advisor) use $X \gg Y$ to mean that $X \geq c Y$ for a sufficiently large constant $c$.  Precisely, we usually use it when we write things like:
$$
f(x) = g(x) + O(h(x)) \quad \Longrightarrow \quad f(x) = g(x) (1 + o(1))
$$
when $g(x) \gg h(x)$.
