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 ...

Initial value problems for first order partial functional almost linear equations with unbounded delay are considered. The functional dependence is represented by the generalized Hale operator with ...

In this paper we will prove the coexistence of unbounded solutions and periodic solutions for the asymmetric oscillator $\ddot{x}+f(\dot{x})+ax^{+}-bx^{-}=\varphi (t,x)$, where a and b are positive ...

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 ...