On Relatively Solid Convex Cones in Real Linear Spaces

Having a convex cone K in an infinite-dimensional real linear space X, Adan and Novo stated (in J Optim Theory Appl 121:515-540, 2004) that the relative algebraic interior of K is nonempty if and only if the relative algebraic interior of the positive dual cone of K is nonempty. In this paper, we show that the direct implication is not true even if K is closed with respect to the finest locally convex topology tau(c) on X, while the reverse implication is not true if K is not tau(c)-closed. However, in the main result of this paper, we prove that the latter implication is true if the algebraic interior of the positive dual cone of K is nonempty; the general case remains an open problem. As a by-product, a result about separation of cones is obtained that improves Theorem 2.2 of the work mentioned above.