Descriptive properties of the set of exposed points of compact convex sets in ℝ³
Petr Holický, Miklós Laczkovich · Proceedings of the American Mathematical Society · 2004
We construct a compact convex subset of R 3 \mathbb R^3 such that the set of its exposed points is not the intersection of an F σ F_{\sigma } set and a G δ G_{\delta } set. The existence of such a set answers a question posed by G. Choquet, H.H. Corson and V.L. Klee.