A geometric form of the Hahn-Banach extension theorem for L0 linear functions and the Goldstine-Weston theorem in random normed modules

Abstract

In this paper, we present a geometric form of the Hahn-Banach extension theorem for $L^0-$linear functions and prove that the geometric form is equivalent to the analytic form of the Hahn-Banach extension theorem. Further, we use the geometric form to give a new proof of a known basic strict separation theorem in random locally convex modules. Finally, using the basic strict separation theorem we establish the Goldstine-Weston theorem in random normed modules under the two kinds of topologies----the $(\epsilon ,\lambda )-$topology and the locally $L^0-$convex topology, and also provide a counterexample showing that the Goldstine-Weston theorem under the locally $L^0-$convex topology can only hold for random normed modules with the countable concatenation property.

14 pages

References in corpus (1)

• Recent progress in random metric theory and its applications to conditional risk measures