Volume 2, Issue 3 Chi-Kwong Li Yiu-Tung Poon Nung-Sing Sze Davis-Wielandt shells of operators Downloads Abstract PDF Full article PDF DOI { copied = true; setTimeout(() => copied = false, 2000) })" :aria-label="copied ? 'DOI copied' : 'Copy DOI'" :title="copied ? 'Copied' : 'Copy DOI'" > Find all available articles from these authors Chi-Kwong Li Yiu-Tung Poon Nung-Sing Sze Find more articles with the same keywords Davis-Wielandt shells generalized numerical ranges spectra operators Find more articles with the same subject classes 47A10 47A12 47B15