Measure, Integration & Real Analysis · Problem 6A.6
Banach Spaces — Sheldon Axler
Mathematics — Measure Theory · metric-spaces-closure-of-open-ball
Problem
(a) Prove that if V is a metric space, f∈V, and r>0, then B(f,r)⊆B(f,r).
(b) Give an example of a metric space V, f∈V, and r>0 such that B(f,r)=B(f,r).