As a generalization of Banaś-Fra̧czieck space, the space Xλ ,p that denotes R 2 endowed with the norm ‖x‖λ ,p = max{λ |x1 |,‖x‖p} for λ > 1 , p 1 and x = (x1,x2) ∈ R2 is well defined. In this note, the exact value of the the James type constants JXλ ,p ,t(1) and von Neumann-Jordan constant CNJ (Xλ ,p) about this space for p 2 are investigated.

The James constant of a Banach space X was introduced by Gao and Lau [3] and has recently been studied by several authors. In this paper, we present some recent results on James constant of 2-dimensional Lorentz sequence space.

We introduce a new class of normalized norms on R 2 which properly contains all absolute normalized norms. We also give a criterion for deciding whether a given norm in this class is uniformly nonsquare. Moreover, an estimate for the James constant is presented and the exact value of some certain norms is computed. This gives a partial answer to the question raised by Kato et al. under the Crea...

Let λ > 0 , Zp,q denote R2 endowed with the norm |x|p,q = (‖x‖p +λ‖x‖q) 1 2 . Recently, James constant J(Zp,q) and von Neumann-Jordan constant CNJ(Zp,q) have been investigated under the two cases of a space 2 p q ∞ and 1 p q 2 . In this note, we show an inequality on these two constants under the case of 1 p 2 q ∞ . As an application, we give a sufficient condition for the space Zp,q with unifo...