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JOURNALS // Funktsional'nyi Analiz i ego Prilozheniya // Archive

Funktsional. Anal. i Prilozhen., 2004 Volume 38, Issue 2, Pages 55–64 (Mi faa107)

This article is cited in 2 papers

Deficiency Indices of a Symmetric Ordinary Differential Operator with Infinitely Many Degeneration Points

Yu. B. Orochko

Moscow State Institute of Electronics and Mathematics

Abstract: Let $H$ be the minimal symmetric operator in $L^2(\mathbb{R})$ generated by the differential expression $(-1)^n(c(x)f^{(n)})^{(n)}$, $n\ge1$, with a real coefficient $c(x)$ that has countably many zeros without finite accumulation points and is infinitely smooth at all points $x\in\mathbb{R}$ with $c(x)\ne0$. We study the value $\operatorname{Def}H$ of the deficiency indices of $H$. It is shown that $\operatorname{Def}H=+\infty$ if infinitely many zeros of $c(x)$ have multiplicities $p$ satisfying the inequality $n-1/2<p<2n-1/2$. Our second result pertains to the case in which the set of zeros of $c(x)$ is bounded neither above nor below. Under this condition, $\operatorname{Def}H=0$ provided that the multiplicity of each zero is greater than or equal to $2n-1/2$. The multiplicities of zeros of $c(x)$ are understood in the paper in a broader sense than in the standard definition.

Keywords: symmetric operator, deficiency indices, degenerate ordinary differential operator.

UDC: 517.98

Received: 30.12.2002

DOI: 10.4213/faa107


 English version:
Functional Analysis and Its Applications, 2004, 38:2, 125–132

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