A version of Lomonosov's theorem for collections of positive operators
Abstract
It is known that for every Banach space X and every proper WOT-closed subalgebra A of L(X), if A contains a compact operator then it is not transitive. That is, there exist non-zero x in X and f in X* such that f(Tx)=0 for all T in A. In the case of algebras of adjoint operators on a dual Banach space, V.Lomonosov extended this as follows: without having a compact operator in the algebra, |f(Tx)| is less than or equal to the essential norm of the pre-adjoint operator T_* for all T in A. In this paper, we prove a similar extension (in case of adjoint operators) of a result of R.Drnovsek. Namely, we prove that if C is a collection of positive adjoint operators on a Banach lattice X satisfying certain conditions, then there exist non-zero positive x in X and f in X* such that f(Tx) is less than or equal to the essential norm of T_* for all T in C.
Keywords
Cite
@article{arxiv.0807.3327,
title = {A version of Lomonosov's theorem for collections of positive operators},
author = {Alexey I. Popov and Vladimir G. Troitsky},
journal= {arXiv preprint arXiv:0807.3327},
year = {2008}
}