Effective construction of a class of positive operators in Hilbert space, which do not admit triangular factorization
arXiv:1009.1762 · doi:10.1016/j.jfa.2010.11.009
Abstract
A class of non-factorable positive operators is constructed. As a result, pure existence theorems in the well-known problems by Ringrose, Kadison and Singer are substituted by concrete examples.