EDB — 0KK

[0KK] Given a topological space \((X,𝜏)\), a base ¹ is a collection \({\mathcal B}\) of open sets (i.e. \({\mathcal B}⊆ 𝜏\)) with the property that every element of \(𝜏\) is an union of elements of \({\mathcal B}\).