Inverse problems in differential operators and spectral theory constitute a vibrant research area where one seeks to determine unknown parameters within differential equations from observed spectral ...

Pseudo-differential operators have emerged as pivotal tools in modern analysis, generalising classical differential operators to encapsulate non-local behaviour via their symbol calculus. Their ...

We show that a strongly continuous operator semigroup can be associated with the functional differential delay equation \begin{equation*}\tag{(FDE)}\begin{cases}x'(t ...

Our aim is to prove one relation between characteristic determinant and norms of orthogonal eigenvectors of eigenvalue problem for fourth order differential operator equation.That relation as appears ...