Characterization of the spectrum of irregular boundary value problem for the Sturm-Liouville operator

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223425We consider the spectral problem generated by the Sturm-Liouville equation with an arbitrary complex-valued potential q(x) and irregular boundary conditions. We establish necessary and sufficient conditions for a set of complex numbers to be the spectrum of such an operator.16 pagesSpectral TheoryFunctional Analysis34A55; 34B24Characterization of the spectrum of irregular boundary value problem for the Sturm-Liouville operatortext