Topological Basis

- Mathematics & Logic -
Pure Mathematics Dictionary
A collection B of open subsets of a topological space X such that every open set in X is a union of elements of B, and for every x in X and B1,B2 in B with x∈B1∩B2 there exists B3 in B with x∈B3⊆B1∩B2; B is called a basis for the topology.