Separation of a topological space
= Separation of a topological space
A separation of a topological space $X$ is a pair of disjoint nonempty open subsets whose union is $X$. A space is <connected> exactly when it has no separation.
= Separation of a topological space
A separation of a topological space $X$ is a pair of disjoint nonempty open subsets whose union is $X$. A space is <connected> exactly when it has no separation.