Operators and Matrices · Volume 2, Issue 3 Davis-Wielandt shells of operators 02-20 Pages 341-355 DOI 10.7153/oam-02-20 Downloads Short PDF Full PDF PNG Authors Chi-Kwong Li Yiu-Tung Poon Nung-Sing Sze Keywords Davis-Wielandt shells generalized numerical ranges spectra operators Subject classes 47A10 47A12 47B15