A counterexample on the closedness of the convex hull of a closed cone in \({\mathbb R}^n\). (Q696133)

In this paper the authors study an interesting counterexample on the closedness of a convex hull of a closed cone in \(\mathbb{R}^n\). Starting from a classical definition of a cone defined on \(\mathbb{R}^n\), they consider a problem not analysed well in the literature concerning the question if the convex hull of a closed cone is closed in \(\mathbb{R}^n\), too. The authors give an example to show that the answer to the question is negative when \(n\geq 3\).