Spectral Theory of Block Multivalued Operator Matrices

Aymen Ammar is Professor at the Department of Mathematics, Faculty of Sciences of Sfax, University of Sfax, Tunisia. He is a co-author of the book, Spectral Theory of Multivalued Linear Operators, with Aref Jeribi. He has published more than 111 paper in several international journals. His areas of interest include spectral theory, matrix operators, transport theory, and linear relations.

Aref Jeribi is Professor in the Department of Mathematics, University of Sfax, Tunisia. He completed his Habilitation of Mathematics and Applications at the University of Sfax, Tunisia, in 2002, and defended his PhD thesis at the University of Corsica Pasquale Paoli, France, in 1998. His research interests include spectral theory, matrix operators, transport theory, Gribov operator, Bargmann space, fixed point theory, Riesz basis and linear relations. He is an author of 13 books, including Problems in Finite Element Methods Aubin Nitsche’s Duality Process, Nodal Methods and Friedrichs Systems, (Springer, 2025), Perturbation Theory for Linear Operators: Denseness and Bases with Applications (Springer, 2021) and Spectral Theory and Applications of Linear Operators and Block Operator Matrices (Springer, 2015) and more than 234 research articles published in reputed journals and conference proceedings.