# Search Results

## You are looking at 1 - 10 of 57 items for :

• "L2"
• Mathematics and Statistics
• All content
Clear All

# Относительные средние поперечники пространств Соболевав L 2(ℝ d )

Analysis Mathematica
Authors: Yongping Liu and Weiwei Xiao

## Abstract

In this paper, in order to consider the problems of relative width on ℝd, we proposed definitions of relative average width which combine the ideas of the relative width and the average width. We established the smallest number M which make the following equality

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\overline K _\sigma (U(W_2^\alpha ),M(W_2^\alpha ),L_2 ({\mathbb{R}}^d )) = \overline d _\sigma (U(W_2^\alpha ),L_2 ({\mathbb{R}}^d ))$$ \end{document}
hold, where U(W 2 α) is the Riesz potential or Bessel potential of the unit ball in L 2(ℝk) and the notations
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\overline K _\sigma$$ \end{document}
(·, ·,L 2(ℝd)) and
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\overline d _\sigma$$ \end{document}
(·, L 2(ℝd)) denote respectively the relative average width in the sense of Kolmogorov and the average width in the sense of Kolmogorov in their given order. In 2001, Subbotin and Telyakovskii got similar results on the relative width of Kolmogorov type. We also proved that
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\overline K _\sigma (U(W_2^\alpha ) \cap B(L_2 (\mathbb{R}^d )),U(W_2^\beta ) \cap B(L_2 (\mathbb{R}^d ))L_2 (\mathbb{R}^d )) = \overline d _\sigma (U(W_2^\alpha ),L_2 (\mathbb{R}^d )),$$ \end{document}
where 0 × β × α.

Restricted access

# Относиелые поперечники классов в L 2(T), определённых линейным дифференциальным оператором в L q (T)

Analysis Mathematica
Author: Weiwei Xiao

## Abstract

In this paper, the smallest number M which makes the equality

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$K_n (W_2^{L_r } (T),MW_2^{L_r } (T),L_2 (T)) = d_n (W_2^{L_r } (T),L_2 (T))$$ \end{document}
valid, is established and the asymptotic order of
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$K_n (W_2^{L_r } (T),W_2^{L_r } (T),L_q (T)),1 \leqslant q \leqslant \infty$$ \end{document}
, is obtained, where
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$W_2^{L_r }$$ \end{document}
(T) is a periodic smooth function class which is determined by a linear differential operator, K n(·, ·, ·) and d n(·, ·) are the relative width and the width in the sense of Kolmogorov, respectively.

Restricted access

# Certain problems of the approximation of functions in two variables by Fourier-Hermite sums in the space L 2(Γ², e -x ² -y ²)

Analysis Mathematica
Authors: V. A. Abilov and M. V. Abilov

## Summary

We give an exact estimate of the deviation of the "triangular" partial sums of the double Fourier-Hermite series of functions of the class L r 2(D) in the space L 2(Γ, e -x -y ).

Restricted access

# Приближение сопряже нных функций суммами Фурье в L 2π p

Analysis Mathematica
Author: S. Baiborodov
Restricted access

# Approximation der Ableitungen von L 2-Funktionalen durch singuläre integrale

Acta Mathematica Hungarica
Author: H. Haf
Restricted access

# L 2(R n )-экстремальные за дачи на основе непольной и нформации

Analysis Mathematica
Author: Liu Yongping
Restricted access

# Bundle Convergence of Cesàro Means of Orthogonal Sequences in Noncommutative L 2-Spaces

Periodica Mathematica Hungarica
Author: Ferenc Móricz
Restricted access

# A functional CLT for the L 2 modulus of continuity of local time

Periodica Mathematica Hungarica
Author: Jay Rosen

## Abstract

We show that as processes in (c, d, t) ∈ C(R 2 × R + 1)

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\frac{{\int_c^d {(L_t^{x + h} - L_t^x )^2 dx - 4h} \int_c^d {L_t^x dx} }} {{h^{3/2} }}\mathop \Rightarrow \limits^\mathcal{L} \left( {\frac{{64}} {3}} \right)^{1/2} \int_c^d {L_t^x d\eta (x)}$$ \end{document}
as h → 0 for Brownian local time L t x. Here η(x) is an independent two-sided Brownian motion.

Restricted access

# On the best approximation of periodic functions by trigonometric polynomials and the exact values of widths of function classes in L 2

Analysis Mathematica
Authors: М. Шлбоэов and С. Влклрчук

## Реэюме

Получены точные неравенства типа Джексона-Стечкина для ос-редненных с весом модулей непрерывности m-го (m ∈ ℕ) порядка. Для классов функций, определенных при помоши мажорант и укаэанных осредненных величин, вычислены точные эначения раэличных n-поперечников при выполнении определенных ограничений на мажоранты.

Restricted access

# The unit balls of $ℒ ( n l ∞ m )$ and $ℒ s ( n l ∞ m )$

Studia Scientiarum Mathematicarum Hungarica
Author: Sung Guen Kim

. Math. (Basel) , 76 ( 2001 ), 73 – 80 . [2] Cavalcante , W. and Pellegrino , D. , Geometry of the closed unit ball of the space of bilinear forms on l2 , arXiv : 1603.01535v2 . [3] Choi , Y. S. , Ki , H. and Kim , S. G. , Extreme

Restricted access