Operators and Matrices · Volume 17, Issue 4 The essential spectrum equalities of 2×2 unbounded upper triangular operator matrices 17-70 Pages 1065-1076 DOI 10.7153/oam-2023-17-70 Downloads Short PDF Full PDF PNG Authors XinRan Liu Deyu Wu Keywords upper triangular operator matrices essential spectrums Fredholm<\i> operators spectral equalities Subject classes 47A53 47A55
