Question

Define base , sub base and local base in a topological space

Answer 1

Local Base for a Topology. Let be atopological space and x ∈ X , then thesub collection is said to be local basesat a point if for belonging to an open set , there exists a member of , such that x ∈ B ⊆ U . It can be defined as, let be a topological space and x ∈ X .