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Keywords:
spectrum; functional differential operator
Summary:
We study conditions of discreteness of spectrum of the functional-differential operator \[ \mathcal {L} u=-u''+p(x)u(x)+\int _{-\infty }^\infty (u(x)-u(s)) {\rm d}_s r(x,s) \] on $(-\infty ,\infty )$. In the absence of the integral term this operator is a one-dimensional Schrödinger operator. In this paper we consider a symmetric operator with real spectrum. Conditions of discreteness are obtained in terms of the first eigenvalue of a truncated operator. We also obtain one simple condition for discreteness of spectrum.
References:
[1] Akhiezer, N. I., Glazman, I. M.: Theory of Linear Operators in Hilbert Space. Translated from the Russian. Dover Publications, New York (1993). MR 1255973
[2] Birman, M. S., Solomjak, M. Z.: Spectral Theory of Self-Adjoint Operators in Hilbert Space. Translated from the Russian. Mathematics and Its Applications. Soviet Series 5 D. Reidel Publishing Company, Dordrecht (1987). MR 1192782
[3] Cohn, D. L.: Measure Theory. Birkhäuser, Boston (1993). MR 1454121 | Zbl 0860.28001
[4] Friedrichs, K.: Spektraltheorie halbbeschränkter Operatoren und Anwendung auf die Spektralzerlegung von Differentialoperatoren I. Math. Ann. 109 (1934), 465-487. DOI 10.1007/BF01449150 | MR 1512905 | Zbl 0008.39203
[5] Friedrichs, K.: Spektraltheorie halbbeschränkter Operatoren und Anwendung auf die Spektralzerlegung von Differentialoperatoren II. Math. Ann. 109 (1934), 685-713. DOI 10.1007/BF01449164 | MR 1512919 | Zbl 0009.07205
[6] Gelfand, I. M., Fomin, S. V.: Calculus of Variations. Translated from the Russian. Prentice-Hall, Englewood Cliffs (1963). MR 0160139
[7] Getimane, M., Labovskiy, S.: On discreteness of spectrum of a functional-differential operator. Funct. Differ. Equ. 20 (2013), 109-121. MR 3238835
[8] Ismagilov, R. S.: Conditions for semiboundedness and discreteness of the spectrum for one-dimensional differential equations. Dokl. Akad. Nauk SSSR 140 (1961), 33-36. MR 0140760
[9] Kantorovich, L. V., Akilov, G. P.: Functional Analysis. Nauka, Moskva (1984), Russian. MR 0788496 | Zbl 0555.46001
[10] Labovskii, S.: Little vibrations of an abstract mechanical system and corresponding eigenvalue problem. Funct. Differ. Equ. 6 (1999), 155-167. MR 1733234 | Zbl 1041.34050
[11] Labovskij, S. M.: On the Sturm-Liouville problem for a linear singular functional-differential equation. Translated from the Russian. Russ. Math. 40 (1996), 50-56. MR 1442139
[12] Labovskiy, S.: Small vibrations of mechanical system. Funct. Differ. Equ. 16 (2009), 447-468. MR 2573916
[13] Maz'ya, V., Shubin, M.: Discreteness of spectrum and positivity criteria for Schrödinger operators. Ann. Math. 162 (2005), 919-942. DOI 10.4007/annals.2005.162.919 | MR 2183285 | Zbl 1106.35043
[14] Molchanov, A. M.: On conditions for discreteness of the spectrum of self-adjoint differential equations of the second order. Tr. Mosk. Mat. Obshch. 2 (1953), 169-199 Russian. MR 0057422
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