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Physical Sciences and Mathematics Commons

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Mathematics

Turkish Journal of Mathematics

Journal

2017

Characteristic function

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Dissipative Operator And Its Cayley Transform, Eki̇n Uğurlu, Kenan Taş Jan 2017

Dissipative Operator And Its Cayley Transform, Eki̇n Uğurlu, Kenan Taş

Turkish Journal of Mathematics

In this paper, we investigate the spectral properties of the maximaldissipative extension of the minimal symmetric differential operatorgenerated by a second order differential expression and dissipative andeigenparameter dependent boundary conditions. For this purpose we use thecharacteristic function of the maximal dissipative operator and inverseoperator. This investigation is done by the characteristic function of theCayley transform of the maximal dissipative operator, which is a completelynonunitary contraction belonging to the class $C_{0}.$ Using Solomyak'smethod we also introduce the self-adjoint dilation of the maximal dissipativeoperator and incoming/outgoing eigenfunctions of the dilation. Moreover, weinvestigate other properties of the Cayley transform of the maximaldissipative operator.


Dirac Systems With Regular And Singular Transmission Effects, Eki̇n Uğurlu Jan 2017

Dirac Systems With Regular And Singular Transmission Effects, Eki̇n Uğurlu

Turkish Journal of Mathematics

In this paper, we investigate the spectral properties of singular eigenparameter dependent dissipative problems in Weyl's limit-circle case with finite transmission conditions. In particular, these transmission conditions are assumed to be regular and singular. To analyze these problems we construct suitable Hilbert spaces with special inner products and linear operators associated with these problems. Using the equivalence of the Lax-Phillips scattering function and Sz-Nagy-Foiaş characteristic functions we prove that all root vectors of these dissipative operators are complete in Hilbert spaces.