Operators and Matrices · Volume 15, Issue 4 Maximal numerical range and quadratic elements in a C✻-algebra 15-93 Pages 1477-1487 DOI 10.7153/oam-2021-15-93 Downloads Short PDF Full PDF PNG Authors El Hassan Benabdi M. Barraa M. K. Chraibi Abderrahim Baghdad Keywords quadratic operator C✻-algebra numerical range maximal numerical range Subject classes 46L05 47A12 47A63