Operators and Matrices · Volume 4, Issue 2 Operator radii and unitary operators 04-14 Pages 273-281 DOI 10.7153/oam-04-14 Downloads Short PDF Full PDF PNG Authors Tsuyoshi Ando Chi-Kwong Li Keywords nitary ϱ-dilation operator radius numerical radius unitary operator Subject classes 47A20 47A12 15A60