Research output: Contribution to journal › Article › peer-review
Threshold approximations for the resolvent of a polynomial nonnegative operator pencil. / Sloushch, V. A. ; Suslina, T. A. .
In: St. Petersburg Mathematical Journal, Vol. 33, No. 2, 04.03.2022, p. 355-385.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Threshold approximations for the resolvent of a polynomial nonnegative operator pencil
AU - Sloushch, V. A.
AU - Suslina, T. A.
N1 - Publisher Copyright: © 2022 American Mathematical Society
PY - 2022/3/4
Y1 - 2022/3/4
N2 - In a Hilbert space (Formula Presented), a family of operators A(t), t ∈ R, is treated admitting a factorization of the form A(t) = X(t)*X(t), where X(t) = X 0+X 1t+· · ·+X pt p, p ≥ 2. It is assumed that the point λ 0 = 0 is an isolated eigenvalue of finite multiplicity for A(0). Let F(t) be the spectral projection of A(t) for the interval [0, δ]. For |t| ≤ t 0, approximation in the operator norm in (Formula Presented) for the projection F(t) with an error O(t 2p) is obtained as well as approximation for the operator A(t)F(t) with an error O(t 4p) (the so-called threshold approximations). The parameters δ and t 0 are controlled explicitly. Using threshold approximations, approximation in the operator norm in (Formula Presented) is found for the resolvent (A(t) + ε 2pI)−1 for |t| ≤ t 0 and small ε > 0 with an error O(1). All approximations mentioned above are given in terms of the spectral characteristics of the operator A(t) near the bottom of the spectrum. The results are aimed at application to homogenization problems for periodic differential operators in the small period limit
AB - In a Hilbert space (Formula Presented), a family of operators A(t), t ∈ R, is treated admitting a factorization of the form A(t) = X(t)*X(t), where X(t) = X 0+X 1t+· · ·+X pt p, p ≥ 2. It is assumed that the point λ 0 = 0 is an isolated eigenvalue of finite multiplicity for A(0). Let F(t) be the spectral projection of A(t) for the interval [0, δ]. For |t| ≤ t 0, approximation in the operator norm in (Formula Presented) for the projection F(t) with an error O(t 2p) is obtained as well as approximation for the operator A(t)F(t) with an error O(t 4p) (the so-called threshold approximations). The parameters δ and t 0 are controlled explicitly. Using threshold approximations, approximation in the operator norm in (Formula Presented) is found for the resolvent (A(t) + ε 2pI)−1 for |t| ≤ t 0 and small ε > 0 with an error O(1). All approximations mentioned above are given in terms of the spectral characteristics of the operator A(t) near the bottom of the spectrum. The results are aimed at application to homogenization problems for periodic differential operators in the small period limit
KW - Analytic perturbation theory
KW - Correctors
KW - Homogenization theory
KW - Polynomial operator pencils
KW - Threshold approximations
UR - https://www.ams.org/journals/spmj/2022-33-02/S1061-0022-2022-01704-5/
UR - http://www.scopus.com/inward/record.url?scp=85099253239&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/0b0d9e47-7c9e-3315-8b64-410eb74c923b/
U2 - 10.1090/spmj/1704
DO - 10.1090/spmj/1704
M3 - Article
VL - 33
SP - 355
EP - 385
JO - St. Petersburg Mathematical Journal
JF - St. Petersburg Mathematical Journal
SN - 1061-0022
IS - 2
ER -
ID: 100093169