Abstract
It is shown that the James constant of the space $\mathbb{R}^2$ endowed with a $\pi/2$-rotation invariant norm coincides with that of its dual space. As a corollary, we have the same statement on symmetric absolute norms on $\mathbb{R}^2$.
Citation
Naoto KOMURO. Kichi-Suke SAITO. Ryotaro TANAKA. "A Sufficient Condition That $J(X^*)=J(X)$ Holds for a Banach Space $X$." Tokyo J. Math. 41 (1) 219 - 223, June 2018. https://doi.org/10.3836/tjm/1502179259
