  In this survey we aim to give a comprehensive overview of results using
sublinear expanders. The term sublinear expanders refers to a variety of
definitions of expanders, which typically are defined to be graphs $G$ such
that every not-too-small and not-too-large set of vertices $U$ has
neighbourhood of size at least $\alpha |U|$, where $\alpha$ is a function of
$n$ and $|U|$. This is in contrast with linear expanders, where $\alpha$ is
typically a constant. :We will briefly describe proof ideas of some of the
results mentioned here, as well as related open problems.
