Linear operators form the cornerstone of analysis in Banach spaces, offering a framework in which one can rigorously study continuity, spectral properties and stability. Banach space theory, with its ...

Proceedings of the American Mathematical Society, Vol. 131, No. 5 (May, 2003), pp. 1539-1551 (13 pages) This paper provides a variety of sufficient conditions for the existence of a nonzero fixed ...

At the University of Vaasa in Finland, mathematician Yosra Barkaoui has successfully generalized a fundamental theorem that had remained confined to “bounded” systems for more than 40 years.

Yosra Barkaoui’s doctoral dissertation in mathematics at the University of Vaasa, Finland, has successfully generalised a fundamental theorem that has been limited to the bounded case. The research ...