2019/07/04 by Mori, Michiya
#FOS: Mathematics #Functional Analysis (math.FA) #Metric Geometry (math.MG) #Operator Algebras (math.OA)
paper · doi:10.48550/arxiv.1907.02172
We prove that, if the closed unit ball of a normed space X has sufficiently many extreme points, then every mapping Φ from X into itself with the following property is affine: For any pair of points in X, there exists a (not necessarily linear) surjective isometry on X that coincides with Φ at the two points. We also consider surjectivity of such a mapping in some special cases including C^*-algebras.