Uniform nonsquareness of direct sums of Banach spaces. (English) Zbl 1189.46009

Betiuk-Pilarska, Anna; Prus, Stanisław

Topol. Methods Nonlinear Anal. 34, No. 1, 181-186 (2009).

Summary: An inequality between James constants of Banach spaces \(X\), and the James constant of their direct sum is obtained. This yields a characterization of uniform nonsquareness of sums of Banach spaces.

MSC:

46B20

Geometry and structure of normed linear spaces

Keywords:

James constants; uniform nonsquareness; sums of Banach spaces