共查询到20条相似文献,搜索用时 31 毫秒
1.
V. V. Zhuk 《Journal of Mathematical Sciences》2009,157(4):592-606
Let
be the Fejér kernel, C be the space of contiuous 2π-periodic functions f with the norm
, let
be the Jackson polynomials of the function f, and let
be the Fejér sums of f. The paper presents upper bounds for certain quantities like
which are exact in order for every function f ∈ C. Special attention is paid to the constants occurring in the inequalities obtained. Bibliography: 14 titles.
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 357, 2008, pp. 90–114. 相似文献
2.
3.
Gwang Hui Kim 《数学学报(英文版)》2009,25(1):29-38
The aim of this paper is to study the stability problem of the generalized sine functional equations as follows:
g(x)f(y)=f(x+y/2)^2-f(x-y/2)^2 f(x)g(y)=f(x+y/2)^2-f(x-y/2)^2,g(x)g(y)=f(x+y/2)^-f(x-y/2)^2
Namely, we have generalized the Hyers Ulam stability of the (pexiderized) sine functional equation. 相似文献
g(x)f(y)=f(x+y/2)^2-f(x-y/2)^2 f(x)g(y)=f(x+y/2)^2-f(x-y/2)^2,g(x)g(y)=f(x+y/2)^-f(x-y/2)^2
Namely, we have generalized the Hyers Ulam stability of the (pexiderized) sine functional equation. 相似文献
4.
Kenji Nishihara 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(4):604-614
We consider the Cauchy problem for the nonlinear dissipative evolution system with ellipticity on one dimensional space
with
S. Q. Tang and H. Zhao [4] have considered the problem and obtained the optimal decay property for suitably small data. In
this paper we derive the asymptotic profile using the Gauss kernel G(t, x), which shows the precise behavior of solution as time tends to infinity. In fact, we will show that the asymptotic formula
holds, where D0, β0 are determined by the data. It is the key point to reformulate the system to the nonlinear parabolic one by suitable changing
variables.
(Received: January 8, 2005) 相似文献
5.
In this paper,the parameterized Marcinkiewicz integrals with variable kernels defined by μΩ^ρ(f)(x)=(∫0^∞│∫│1-y│≤t Ω(x,x-y)/│x-y│^n-p f(y)dy│^2dt/t1+2p)^1/2 are investigated.It is proved that if Ω∈ L∞(R^n) × L^r(S^n-1)(r〉(n-n1p'/n) is an odd function in the second variable y,then the operator μΩ^ρ is bounded from L^p(R^n) to L^p(R^n) for 1 〈 p ≤ max{(n+1)/2,2}.It is also proved that,if Ω satisfies the L^1-Dini condition,then μΩ^ρ is of type(p,p) for 1 〈 p ≤ 2,of the weak type(1,1) and bounded from H1 to L1. 相似文献
6.
Jin Deng 《应用数学学报(英文版)》2006,22(1):163-170
In this paper, a nonlinear difference system {xn=βxn-1+f(yn-κ),yn=βyn-1+f(xn-κ),n∈N is considered a,nd sufficient conditions for the existe~lce of the stable 2κ + 1 periodic solution are obtained. 相似文献
7.
V. A. Kofanov 《Ukrainian Mathematical Journal》2008,60(10):1557-1573
We obtain a new sharp inequality for the local norms of functions x ∈ L
∞, ∞
r
(R), namely,
where φ
r
is the perfect Euler spline, on the segment [a, b] of monotonicity of x for q ≥ 1 and for arbitrary q > 0 in the case where r = 2 or r = 3.
As a corollary, we prove the well-known Ligun inequality for periodic functions x ∈ L
∞
r
, namely,
for q ∈ [0, 1) in the case where r = 2 or r = 3.
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 10, pp. 1338–1349, October, 2008. 相似文献
8.
Precise Asymptotics in the Law of the Iterated Logarithm of Moving-Average Processes 总被引:1,自引:0,他引:1
Yun Xia LI Li Xin ZHANG 《数学学报(英文版)》2006,22(1):143-156
In this paper, we discuss the moving-average process Xk = ∑i=-∞ ^∞ ai+kεi, where {εi;-∞ 〈 i 〈 ∞} is a doubly infinite sequence of identically distributed ψ-mixing or negatively associated random variables with mean zeros and finite variances, {ai;-∞ 〈 i 〈 -∞) is an absolutely solutely summable sequence of real numbers. 相似文献
9.
Shi Ping LU Wei Gao GE 《数学学报(英文版)》2005,21(6):1309-1314
Thc main aim of this paper is to use the continuation theorem of coincidence degree theory for studying the existence of periodic solutions to a kind of neutral functional differential equation as follows:(x(t)-^n∑i=1cix(t-ri))″=f(x(t))x′+g(x(t-τ))+p(t).In order to do so, we analyze the structure of the linear difference operator A : C2π→C2π, [Ax](t) =x(t)-∑^ni=1cix(t-ri)to determine some flmdamental properties first, which we are going to use throughout this paper. Meanwhile, we also prove some new inequalities which are useful for estimating a priori bounds of periodie solutions. 相似文献
10.
Mohammad Sal Moslehian 《Bulletin of the Brazilian Mathematical Society》2007,38(4):611-622
In this paper, we establish the generalized Hyers–Ulam–Rassias stability of C*-ternary ring homomorphisms associated to the Trif functional equation
相似文献
11.
V. V. Zhuk 《Journal of Mathematical Sciences》2009,157(4):607-622
Let C be the space of continuous 2π-periodic functions f with the norm
. Let
, where
, be the Jackson polynomials of a function f, E
n
(f) be the best approximation of f in the space C by trigonometric polynomials of order n, and let
, be the function trigonometrically conjugate to the primitive of f. The paper establishes results of the following types:
where the symbol ≈ is independent of f and n. Bibliography: 7 titles.
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 357, 2008, pp. 115–142. 相似文献
12.
Zhi-ting Xu 《应用数学学报(英文版)》2007,23(4):569-578
Some oscillation theorems are given for the nonlinear second order elliptic equationsum from i,j=1 to N D_i[a_(ij)(x)Ψ(y)||▽y||~(p-2)D_(jy)] c(x)f(y)=0.The results are extensions of modified Riccati techniques and include recent results of Usami. 相似文献
13.
We obtain the new exact Kolmogorov-type inequality
for 2-periodic functions
and any k, r N, k < r. We present applications of this inequality to problems of approximation of one class of functions by another class and estimates of K-functional type. 相似文献
14.
Feng-de Chen Jin-lin Shi School of Mathematics Computer Fuzhou University Fuzhou China 《应用数学学报(英文版)》2005,21(1):49-60
With the help of a continuation theorem based on Gaines and Mawhin's coincidence degree, easily verifiable criteria are established for the global existence of positive periodic solutions of the following nonlinear state dependent delays predator-prey system where a_i(t),c_j(t),d_i(t) are continuous positive periodic functions with periodic ω>0, b_1(t),b_2(t) are continuous periodic functions with periodic ωand ∫_0~ωbi(t)dt>0. T_i,σ_j, p_i (i=1,2,…,n, j=1, 2,…,m) are continuous and ω-periodic with respect to their first arguments, respectively, α_i, β_j,γ_i(i=1,2,…,n, j=1,2, …, m) are positive constants. 相似文献
15.
In this paper, we consider the functional differential equation with impulsive perturbations
$ \left\{ {{*{20}{c}} {{x^{\prime}}(t) = f\left( {t,{x_t}} \right),} \hfill & {t \geq {t_0},\quad t \ne {t_k},\quad x \in {\mathbb{R}^n},} \hfill \\ {\Delta x(t) = {I_k}\left( {t,x\left( {{t^{-} }} \right)} \right),} \hfill & {t = {t_k},\quad k \in {\mathbb{Z}^{+} }.} \hfill \\ } \right. $ \left\{ {\begin{array}{*{20}{c}} {{x^{\prime}}(t) = f\left( {t,{x_t}} \right),} \hfill & {t \geq {t_0},\quad t \ne {t_k},\quad x \in {\mathbb{R}^n},} \hfill \\ {\Delta x(t) = {I_k}\left( {t,x\left( {{t^{-} }} \right)} \right),} \hfill & {t = {t_k},\quad k \in {\mathbb{Z}^{+} }.} \hfill \\ \end{array} } \right. 相似文献
16.
Shi Ping LU Wei Gao GE Zu Xiu ZHENG 《数学学报(英文版)》2005,21(5):1149-1158
In this paper, the authors consider the existence of periodic solutions for a kind of second neutral functional differential equation as follows:(x(t) - cx(t -τ)" = g(t, x(t - μ(t))) + e(t),in the critical case |c| = 1. By employing Mawhin's continuation theorem and some analysis techniques, some new results are obtained. 相似文献
17.
Let = (1,...,d) be a vector with positive components and let D be the corresponding mixed derivative (of order j with respect to the jth variable). In the case where d > 1 and 0 < k < r are arbitrary, we prove that
18.
G. P. Kukhta 《Journal of Mathematical Sciences》1992,60(2):1396-1398
By the Fourier method a solution of the equation
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