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The asymptotics of eigenvalues and trace formula of operator associated with one singular problem Boundary Value Problems 2012, 2012:8 doi:10.1186/1687-2770-2012-8 Nigar M Aslanova nigar

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The asymptotics of eigenvalues and trace formula of operator associated with

one singular problem

Boundary Value Problems 2012, 2012:8 doi:10.1186/1687-2770-2012-8

Nigar M Aslanova (nigar.aslanova@yahoo.com)

ISSN 1687-2770

Article type Research

Submission date 14 September 2011

Acceptance date 23 January 2012

Publication date 23 January 2012

Article URL http://www.boundaryvalueproblems.com/content/2012/1/8

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The asymptpotics of eigenvalues and trace formula of operator associated

with one singular problem

Nigar M Aslanova Institute of Mathematics and Mechanics of NAS of Azerbaijan,

Baku, Azerbaijan Mathematics Department, Khazar University, Baku, Azerbaijan

Email address: nigar.aslanova@yahoo.com

Abstract

In the article, spectrum of operator generated by differential

oper-ator expression given on semi axis is investigated and proved formula

for regularized trace of this operator

com-ϕ1, ϕ2, , respectively.

Suppose that operator-valued function q(x) is weakly measurable, kq(x)k

is bounded on [0, ∞), q ∗ (x) = q(x)∀x ∈ [o, ∞) The following properties

In the case q(x) ≡ 0 in L2(H, (0, ∞)) associate with problems (1), (2) a self-adjoint operator L0 whose domain is

D(L0) = {y(x) ∈ L2(H, (0, ∞)/l[y] ∈ L2(H, (0, ∞), y 0 (0) = 0}

In the case q(x) 6= 0 denote the corresponding operator by L, so L =

L0+ q.

In this article the asymptotics of eigenvalues and the trace formula of

operator L will be studied.

In [1] the regularized traces of all orders of the operator generated by theexpression

The asymptotics of eigenvalues and trace formulas for operators generated

by differential expressions with operator coefficients are studied, for example,

in [3–7] We could also refer to papers [8–10] where trace formulas for stract operators are obtained Trace formulas are used for evaluation of firsteigenvalues, they have application to inverse problems, index theory of oper-ators and so forth For further detailed discussions of the subject refer to [11].

ab-1 The asymptotic formula for eigenvalues of

L0 and L

One could easily show that under conditions A > E, A −1 ∈ σ ∞, the spectrum

of L0 is discrete

Suppose that γ k ∼ ak α (k → ∞, a > 0, α > 0) Denote y k (x) = (y(x), ϕ k)

Then by virtue of the spectral expansion of the self-adjoint operator A we get the following boundary-value problem for the coefficients y k (x):

3(x + γ k − λ)

3 2

¾

(1.3)

and in the case x + γ k < λ we can write it as a function of real argument as

3(λ − γ k − x)

3 2

¶

+ J −1

µ2

3(λ − γ k − x)

3 2

µ2

3(λ − γ k − x)

3 2

¶

+ J −1 3

µ2

3(λ − γ k − x)

3 2

¶¾

= 0 (1.5)

at least for one γ k (λ 6= γ k ) Therefore, the spectrum of the operator L0

consists of those real values of λ 6= γ k such that at least for one k

z2

·

J2 3

µ2

3z

3

¶

− J −2 3

µ2

Prove the following two lemmas which we will need further

Lemma 1.1 Equation (1.6) has only real roots.

Proof Suppose that z = iα, α ∈ R, α 6= 0 Then the operator associated

¡

z2y k (x), y k (x)¢= −α2(y k (x), y k (x)) < 0 which is contradiction Then z can be only real, otherwise, the selfadjoint

operator corresponding to (1.7), (1.8) will have nonreal eigenvalues, which isimpossible The lemma is proved

Now, find the asymptotics of the solutions of Equation (1.6) By virtue

of the asymptotics for large |z| [12, p 975]

J ν (z) =

r2

+ O

µ1

m23

¶

, (1.10) where m is a large integer Therefore, the statement of the following lemma

is true

Lemma 1.2 For the eigenvalues of L0 the following asymptotic is true

λ m,k = γ k + α m2, α m = cm13 + O

µ1

m23

¶

(1.11)

For large |z| consider the rectangular contour l with vertices at the points

The following lemma is true

Lemma 1.3 For a sufficiently large integer N the number of the roots

of the equation inside l is N + O(1).

Proof For large |z| we have

3z

3

¶

− J −2 3

µ2

πz3

µcos

µ2

3z

3+ π12

¶¶ µ

1 + O

µ1

πz

µsin

µ2

3z

3− π

4

¶ Therefore, thenumber of the zeros of function

z2

·

J2

µ2

3z

3

¶¸

inside l is N + O(1).

Now, by using the above results , derive the asymptotic formula for the

(a + ε) k α + (c + ε) m2 < λ, (1.14)

N 0 (λ) is the number of the positive integer pairs (m, k) satisfying the

3, α =

23

(1.16)

2 Trace formula

The following lemma is true

Lemma 2.1 Let the conditions of Lemma 1.4 hold Then for α > 2

That is why one could choose a subsequence n1 < n2 < n m < , that

for each k ≥ n m holds µ k − d

We will call limm→∞Pn m

n=1 (λ n − µ n) a regularized trace of the operator

L It will be shown later it is independent of the choice of {n m } satisfying

the hypothesis of Lemma 2.1

From (1.16) it is obvious that for α > 2 resolvents R(L0) and R(L) are trace class operators By using Lemma 2.1 for α > 2 one can prove the

following lemma

Lemma 2.2 Let kq(x)k < const on the interval [0, ∞) and also the

conditions of Lemma 1.6 hold Then for α > 2

where {ψ n } are orthonormal eigenvectors of the operator L0.

The proof of this lemma is analogous to the proof of Lemma 2 and orem 2 from [8] For this reason we will not derive it here

The-The orthogonal eigen-vectors of the operator L0 in L2((0, ∞), H) are

to these values denote by ψ (x, α2) and ψ (x, β2) Multiplying the first of

the obtained equations by ψ (x, β2), the second by ψ (x, α2), subtracting thesecond one from the first one and integrating from zero to infinity we get

¡2

3α3¢

− J −2 3

¡2

3α3¢o n

J1 3

¡2

3β3¢

+ J −1 3

¡2

3β3¢o

α2− β2

3β

3

¶

− J −2 3

µ2

3β

3

¶¶ µ

J1 3

µ2

3β

3

¶

+ J −1 3

µ2

3β

3

¶¶+

3β

3

¶

+ J −1 3

µ2

3β

3

¶¶ µ

J2 3

µ2

3α

3

¶

− J −2 3

µ2

µ2

3α

3

¶¶2+

µ

J1 3

µ2

3α

3

¶

+ J −1 3

µ2

3β

3

¶¾

= 0

3α

3

¶

+ J −1 3

µ2

¡2

3α3

m

¢´ϕ k (2.8) Lemma 2.3 If the operator-valued function q(x) has property 1 and

3α

2

¶3 2

+ J −1

µ2

3α

2

¶3 2

µ23

¡

x − α2

m

¢3 2

¶

∼ e

− √ −z3

−z ,

α ε m

lim

ε→0

−α ε m

Z

α ε m

The lemma is proved

By using Lemma 2.3 prove the following theorem

Theorem 2.1 Let the conditions of Lemma 1.6 hold If the

operator-valued function q (x) has properties 1–3, then it holds the formula

By taking in place of zero x in (2.6) one can show that

¡

z2− x¢3

¶¶2+

+

µ

J2 3

µ23

¡

z2− x¢32

¶

− J −2 3

µ23

3z

3

¶

− J −2 3

µ2

3z

3

¶are simple,

otherwise

µ

J2

µ2

µ2

µ2

µ2

Denote z2 − x = f (x, z) and the right hand side of (2.14) by G(f (x, z).

sum T N (x) Denoting J2

3

µ2

3z

3

¶

− J −2 3

µ2

Consequently, by (2.16), (2.17), (2.22) and the relation

µ

J2 3

µ2

3z

3

¶

− J −2 3

µ2

µ2

µ2

3α

3

m

¶+ 1

α3

m

J −2 3

µ2

µ2

µ2

µ2

Consider the right hand side of the contour with vertices at A N and

A N + iB By using the asymptotics

On the side of the contour with the vertices at ±A N + iB

[2] Gasymov, MG, Levitan, BM: About sum of differences of two singularSturm–Liouville operators Dokl AN SSSR 151(5), 1014–1017 (1953)[3] Rybak, MA: About asymptotic of eigenvalues of some boundary valueproblems for operator Sturm–Liouville equation Ukr Math J 32(2),248–252 (1980)

[4] Qorbachuk, VI, Rybak, MA: About self-adjoint extensions of minimaloperator generated by Sturm–Liouville expression with operator poten-tials and nonhomogeneous bondary conditions Dokl AN URSR Ser A

4, 300–304 (1975)

[5] Aliyev, BA: Asymptotic behavior of eigenvalues of one boundary valueproblem for elliptic differential operator equation of second order Ukr.Math J 5(8), 1146–1152 (2006)

[6] Bayramoglu, M, Aslanova, NM: Distribution of eigenvalues and traceformula of operator Sturm–Liouville equation Ukr Math J 62(7), 867–

877 (2010)

[7] Aslanova, NM: Study of the asymptotic eigenvalue distribution and traceformula of second order operator-differential equation J Bound ValueProbl 7, 13 (2011)

[8] Maksudov, FG, Bayramoglu, M, Adygozalov, AA: On regularized trace

of operator Sturm–Liouville on finite segment with unbounded operatorcoefficient Dokl AN SSSR 277(4), 795–799 (1984)

[9] Bayramoglu, M, Sahinturk, H: Higher order regularized trace formulafor the regular Sturm–Liouville equation contained spectral parameter

in the boundary condition Appl Math Comput 186(2), 1591–1599(2007)

[10] Aslanova, NM: Trace formula of one boundary value problem for Sturm–Liouville operator equation Sib J Math 49(6), 1207–1215 (2008)

[11] Sadovnichii, VA, Podolskii, VE: Traces of operators Uspekh Math.Nauk 61:5(371), 89–156 (2006)

[12] Gradstein, IS, Ryzhik, IM: Table of Integrals, Sums, Series and ucts, p 1108 Nauka, Moscow (1971)

Prod-[13] Qorbachuk VI, Qorbachuk ML: On some classes of boundaryvalue lems for Sturm–Liouville equation with operator-valued potential Ukr.Math J 24(3), 291–305 (1972)