The set $X/R$ consists of the <equivalence classes>, with canonical surjection $q:x\mapsto[x]$. The <quotient topology> declares $V\subseteq X/R$ open exactly when $q^{-1}(V)$ is open in $X$. This makes $q$ <continuous> and is the finest topology on the quotient set doing so.

Solution

Past exam of the Probability, statistics and options II course of the University of Oxford / 2009 / E / E4 / a / iii / Solution

 Solution (source code)