Convex Transitive Norms on Spaces of Continuous Functions
Departamento de Matemáticas, Universidad de Extremadura Avenida de Elvas, ES-06071 Badajoz, Spain; fcabello{at}unex.es
Received 1 September 2002. Revision received 4 June 2003.
A norm on a Banach space X is called maximal when no equivalent norm has a larger group of isometries. If, besides this, there is no equivalent norm with the same isometries (apart from its scalar multiples), the norm is said to be uniquely maximal, which is equivalent to the convex-transitivity of X: the convex hull of the orbits under the action of the isometry group on the unit sphere is dense in the unit ball of X. The main result of the paper is that the complex C0(
) is convex-transitive in its natural supremum norm if
is a connected manifold (without boundary). As a complement, it is shown that if
is a connected manifold of dimension at least two, then the diameter norm is convex transitive on the corresponding space of real functions. 2000 Mathematics Subject Classification 46B15, 47B99
Supported in part by DGICYT project BFM 20010387.