Izvestiya of Saratov University. Mathematics. Mechanics. Informatics
RUS  ENG    JOURNALS   PEOPLE   ORGANISATIONS   CONFERENCES   SEMINARS   VIDEO LIBRARY   PACKAGE AMSBIB  
General information
Latest issue
Archive
Impact factor

Search papers
Search references

RSS
Latest issue
Current issues
Archive issues
What is RSS



Izv. Saratov Univ. Math. Mech. Inform.:
Year:
Volume:
Issue:
Page:
Find






Personal entry:
Login:
Password:
Save password
Enter
Forgotten password?
Register


Izvestiya of Saratov University. Mathematics. Mechanics. Informatics, 2022, Volume 22, Issue 4, Pages 416–429
DOI: https://doi.org/10.18500/1816-9791-2022-22-4-416-429
(Mi isu953)
 

Scientific Part
Mathematics

Representation of functions on a line by a series of exponential monomials

A. S. Krivosheeva, O. A. Krivosheevab

a Institute of Mathematics with Computing Centre, Ufa Federal Research Center, RAS, 112 Chernyshevsky St., Ufa 450008, Russia
b Bashkir State University, 32 Zaki Validi St., Ufa 450076, Russia
References:
Abstract: In this work, we consider the weight spaces of integrable functions $L_p^\omega$ ($p\geq 1$) and continuous functions $C^\omega$ on the real line. Let $\Lambda=\{\lambda_k,n_k\}$ be an unbounded increasing sequence of positive numbers $\lambda_k$ and their multiplicities $n_k$, $\mathcal{E}(\Lambda)=\{t^n e^{\lambda_k t}\}$ be a system of exponential monomials constructed from the sequence $\Lambda$. We study the subspaces $W^p (\Lambda,\omega)$ and $W^0 (\Lambda,\omega)$, which are the closures of the linear span of the system $\mathcal{E}(\Lambda)$ in the spaces $L_p^\omega$ and $C^\omega$, respectively. Under natural constraints on $\Lambda$ (the finiteness of the condensation index $S_\Lambda$ and $n_k/\lambda_k\leq c$, $k\geq 1$) and on the convex weight $\omega$, conditions are obtained under which each function of these subspaces continues to an entire function and is represented by a series in the system $\mathcal{E}(\Lambda)$ that converges absolutely and uniformly on compact sets in the plane. In contrast to the previously known results for the specified representation problem, we do not require that the sequence $\Lambda$ has a density, and we do not impose the separability condition: $\lambda_{k+1}-\lambda_k\geq h$, $k\geq 1$ (instead, the condition of equality to zero of the special condensation index is used).
Key words: series of exponential monomials, weight space, analytic continuation, condensation index.
Funding agency Grant number
Contest «Young Russian Mathematics»
The work of O. A. Krivosheeva is supported in part by the Young Russian Mathematics award.
Received: 18.03.2022
Revised: 15.04.2022
Bibliographic databases:
Document Type: Article
UDC: 517.98
Language: Russian
Citation: A. S. Krivosheev, O. A. Krivosheeva, “Representation of functions on a line by a series of exponential monomials”, Izv. Saratov Univ. Math. Mech. Inform., 22:4 (2022), 416–429
Citation in format AMSBIB
\Bibitem{KriKri22}
\by A.~S.~Krivosheev, O.~A.~Krivosheeva
\paper Representation of functions on a line by a series of exponential monomials
\jour Izv. Saratov Univ. Math. Mech. Inform.
\yr 2022
\vol 22
\issue 4
\pages 416--429
\mathnet{http://mi.mathnet.ru/isu953}
\crossref{https://doi.org/10.18500/1816-9791-2022-22-4-416-429}
\mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=4539336}
\edn{https://elibrary.ru/TPUWZW}
Linking options:
  • https://www.mathnet.ru/eng/isu953
  • https://www.mathnet.ru/eng/isu/v22/i4/p416
  • Citing articles in Google Scholar: Russian citations, English citations
    Related articles in Google Scholar: Russian articles, English articles
    Izvestiya of Saratov University. Mathematics. Mechanics. Informatics
     
      Contact us:
     Terms of Use  Registration to the website  Logotypes © Steklov Mathematical Institute RAS, 2024