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Classes Of Convolutions With A Singular Family Of Kernels : Sharp Constants For Approximation By Spaces Of Shifts. / Vinogradov, O. L.
в: St. Petersburg Mathematical Journal, Том 32, № 2, 01.2021, стр. 233-260.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Classes Of Convolutions With A Singular Family Of Kernels
T2 - Sharp Constants For Approximation By Spaces Of Shifts
AU - Vinogradov, O. L.
N1 - Publisher Copyright: © 2021 American Mathematical Society
PY - 2021/1
Y1 - 2021/1
N2 - Let σ > 0, and let (Formula Presented). The paper is devoted to approximation of classes of functions f for every ε > 0 representable as (Formula Presented) where Fε is an entire function of type not exceeding ε, (Formula Presented), and (Formula Presented) The approximating space SB consists of functions of the form (Formula Presented). Under some conditions on G = {Gε} and B, linear operators Xσ,G,B with values in SB are constructed for which (Formula Presented) the constant Kσ,G (it is an analog of the well-known Favard constant) cannot be reduced, even if one replaces the left-hand side by the best approximation by the space SB. The results of the paper generalize classical inequalities for approximations by entire functions of exponential type and by splines.
AB - Let σ > 0, and let (Formula Presented). The paper is devoted to approximation of classes of functions f for every ε > 0 representable as (Formula Presented) where Fε is an entire function of type not exceeding ε, (Formula Presented), and (Formula Presented) The approximating space SB consists of functions of the form (Formula Presented). Under some conditions on G = {Gε} and B, linear operators Xσ,G,B with values in SB are constructed for which (Formula Presented) the constant Kσ,G (it is an analog of the well-known Favard constant) cannot be reduced, even if one replaces the left-hand side by the best approximation by the space SB. The results of the paper generalize classical inequalities for approximations by entire functions of exponential type and by splines.
KW - Akhiezer–Kre˘ın–Favard type inequalities
KW - convolution
KW - sharp constants
KW - Spaces of shifts
UR - http://www.scopus.com/inward/record.url?scp=85102835186&partnerID=8YFLogxK
U2 - 10.1090/spmj/1646
DO - 10.1090/spmj/1646
M3 - Article
AN - SCOPUS:85102835186
VL - 32
SP - 233
EP - 260
JO - St. Petersburg Mathematical Journal
JF - St. Petersburg Mathematical Journal
SN - 1061-0022
IS - 2
ER -
ID: 101356512