Von Neumann]Jordan Constant of Absolute Normalized Norms on C2

We determine and estimate the von Neumann]Jordan constant of absolute normalized norms on C2 by means of their corresponding continuous convex functions onw0, 1x. This provides many new interesting examples including those of non- lp-type as well as some previous ones. It is also shown that all such norms are uniformly non-square except l 1- and l`-norms