Representations of starshaped sets in normed linear spaces (Q1577661)

Let \(X\) be either a real normed linear space or a real reflexive Banach space and let \(S\) be a nonempty closed connected subset of \(X\). The kernel of \(S\) is the subset \(\text{ker } S\) of \(S\) consisting of points which can be joined with all points of \(S\) by segments contained in \(S\). Various representations of \(\text{ ker} S\) as intersections of convex hulls of ``visibility sets'' associated with some boundary points of \(S\) have been studied by Borwein and Strojwas, Stavrakas, and by the author (see Introduction for a comprehensive survey). The paper under review strengthens and complements the earlier results.