Extreme points of the complex binary trilinear ball
Volume 138 / 2000
Studia Mathematica 138 (2000), 81-92
DOI: 10.4064/sm-138-1-81-92
Abstract
We characterize all the extreme points of the unit ball in the space of trilinear forms on the Hilbert space $ℂ^2$. This answers a question posed by R. Grząślewicz and K. John [7], who solved the corresponding problem for the real Hilbert space $ℝ^2$. As an application we determine the best constant in the inequality between the Hilbert-Schmidt norm and the norm of trilinear forms.
