Nearest points and delta convex functions in Banach spaces
Jonathan Michael Borwein, Ohad Giladi · NOVA (University of Newcastle Australia) · 2016
Given a closed set C in a Banach space (X, || · ||), a point x ∈ X is said to have a nearest point in C if there exists z ∈ C such that dC(x) = ||x - z||, where dC is the distance of x from C. We survey the problem of studying the size of the set of points in X which have nearest points in C. We then turn to the topic of delta convex functions and indicate how it is related to finding nearest points.