Conditions for Linear Dependence of Two Operators
Bojan Kuzma, Gorazd Lešnjak, Chi-Kwong Li, Tatjana Petek, Leiba Rodman · Birkhäuser Basel eBooks · 2010
The linear dependence property of two Hilbert space operators is expressed in terms of equality of size of values of certain sesquilinear and quadratic forms associated with the operators. The forms are based on qnumerical ranges.