Contractivity, Complete Contractivity and Curvature inequalities
Abstract
Let be a norm on given by the formula for some choice of an -tuple of linearly independent matrices Let be the unit ball with respect to the norm %For a holomorphic function on let %\rho_{V}(f):=\left ( %\begin{smallmatrix} %f(w)I_p& \sum_{i=1}^{m} \partial_if(w)V_{i} \\ %0 & f(w)I_q %\end{smallmatrix}\right ), where are %matrices. Given matrices and a function the algebra of function holomorphic on an open set containing the closed unit ball define Clearly, defines an algebra homomorphism. We study contractivity (resp. complete contractivity) of such homomorphisms. The characterization of those balls in for which contractive linear maps are always completely contractive remained open. We answer this question for balls of the form in The class of homomorphisms of the form arise from localization of operators in the Cowen-Douglas class of The (complete) contractivity of a homomorphism in this class naturally produces inequalities for the curvature of the corresponding Cowen-Douglas bundle. This connection and some of its very interesting consequences are discussed.
Cite
@article{arxiv.1408.2389,
title = {Contractivity, Complete Contractivity and Curvature inequalities},
author = {Avijit Pal},
journal= {arXiv preprint arXiv:1408.2389},
year = {2014}
}
Comments
This thesis was submitted at the Indian Institute of Science, Bangalore