| Abstrakt: |
In this article we consider the study of the -differentiability and -ifferentiability for convex functions, not only in the general context of topological vector spaces (t.v.s.), but also in the context of Banach spaces. We study a special class of Banach spaces named Stegall spaces, denoted by G, which is located between the Asplund -spaces and Asplund G-spaces (G-Asplund). We present a self-contained proof of the Stegall theorem, without appealing to the huge number of references required in some proofs available in the classical literature. This requires a thorough study of a very special type of multivalued functions between Banach spaces known as usco multi-functions. [ABSTRACT FROM AUTHOR] |
