Two Geometric Constants for Operators Acting on a Separable Banach Space
The main result of this paper is the following: A separable Banach space is reflexive if and only if the infimum of the Gelfand numbers of any bounded linear operator defined on can be computed by means of just one sequence on nested, closed, finite codimensional subspaces with null intersection.
1980 Mathematics Subject Classification (1985 revision): 47A10, 47A53, 46B10, 40A05.