• MakaleAçık Erişim2026Scopus SJRQ2
    Eigenfunction Expansion and Parseval Identity of β-Dirac Operators on the Whole Line

    Koşar, Nida Palamut; Koşar, Cem; Akcay, Ozge

    In the present work, we investigate a (Formula presented.) -Dirac problem on the whole-line. Our primary objectives are threefold: to demonstrate the existence of a spectral function, to deduce the associated Parseval identity, and to formulate an eigenfunction expansion theorem that characterizes the behavior of the problem under consideration.

  • MakaleAçık Erişim2024Scopus SJRQ4
    Investigation of the Spectrum of Nonself-Adjoint Discontinuous Sturm-Liouville Operator

    Akçay, Özge; Koşar, Nida Palamut

    In this paper, we study nonself-adjoint Sturm-Liouville operator containing both the discontinuous coefficient and discontinuity conditions at some point on the positive half-line. The eigenvalues and the spectral singularities of this problem are examined and it is proved that this problem has a finite number of spectral singularities and eigenvalues with finite multiplicities under two different additional conditions. Furthermore, the principal functions corresponding to the eigenvalues and the spectral singularities of this operator are determined.