2×2 operator matrix with real parameter and its spectrum Elyor B. Dilmurodov, Nargiza A. Tosheva, Nabiya A. Turayeva, Bolatbek T. Karamatov and Durdona Sh. Shokirova E3S Web Conf., 587 (2024) 03002 Published online: 07 November 2024 DOI: 10.1051/e3sconf/202458703002