共查询到20条相似文献,搜索用时 109 毫秒
1.
Bin Heng SONG Huai Yu JIAN 《数学学报(英文版)》2005,21(5):1183-1190
We establish the existence of fundamental solutions for the anisotropic porous medium equation, ut = ∑n i=1(u^mi)xixi in R^n × (O,∞), where m1,m2,..., and mn, are positive constants satisfying min1≤i≤n{mi}≤ 1, ∑i^n=1 mi 〉 n - 2, and max1≤i≤n{mi} ≤1/n(2 + ∑i^n=1 mi). 相似文献
2.
Zheng Yan LIN Sung Chul LEE 《数学学报(英文版)》2006,22(2):535-544
Let {Xn,n ≥ 0} be an AR(1) process. Let Q(n) be the rescaled range statistic, or the R/S statistic for {Xn} which is given by (max1≤k≤n(∑j=1^k(Xj - ^-Xn)) - min 1≤k≤n(∑j=1^k( Xj - ^Xn ))) /(n ^-1∑j=1^n(Xj -^-Xn)^2)^1/2 where ^-Xn = n^-1 ∑j=1^nXj. In this paper we show a law of iterated logarithm for rescaled range statistics Q(n) for AR(1) model. 相似文献
3.
Horst Alzer 《Proceedings Mathematical Sciences》2010,120(2):131-137
Let n ≥ 1 be an integer and let P
n
be the class of polynomials P of degree at most n satisfying z
n
P(1/z) = P(z) for all z ∈ C. Moreover, let r be an integer with 1 ≤ r ≤ n. Then we have for all P ∈ P
n
:
$
\alpha _n (r)\int_0^{2\pi } {|P(e^{it} )|^2 dt} \leqslant \int_0^{2\pi } {|P^r (e^{it} )|^2 dt} \leqslant \beta _n (r)\int_0^{2\pi } {|P(e^{it} )|^2 dt}
$
\alpha _n (r)\int_0^{2\pi } {|P(e^{it} )|^2 dt} \leqslant \int_0^{2\pi } {|P^r (e^{it} )|^2 dt} \leqslant \beta _n (r)\int_0^{2\pi } {|P(e^{it} )|^2 dt}
相似文献
4.
Zhang Lixin 《数学学报(英文版)》1998,14(1):113-124
Let {X, X
n
;n>-1} be a sequence of i.i.d.r.v.s withEX=0 andEX
2=σ2(0 < σ < ∞).
we obtain some sufficient and necessary conditions for
5.
Complete moment and integral convergence for sums of negatively associated random variables 总被引:2,自引:0,他引:2
For a sequence of identically distributed negatively associated random variables {Xn; n ≥ 1} with partial sums Sn = ∑i=1^n Xi, n ≥ 1, refinements are presented of the classical Baum-Katz and Lai complete convergence theorems. More specifically, necessary and sufficient moment conditions are provided for complete moment convergence of the form ∑n≥n0 n^r-2-1/pq anE(max1≤k≤n|Sk|^1/q-∈bn^1/qp)^+〈∞to hold where r 〉 1, q 〉 0 and either n0 = 1,0 〈 p 〈 2, an = 1,bn = n or n0 = 3,p = 2, an = 1 (log n) ^1/2q, bn=n log n. These results extend results of Chow and of Li and Spataru from the indepen- dent and identically distributed case to the identically distributed negatively associated setting. The complete moment convergence is also shown to be equivalent to a form of complete integral convergence. 相似文献
6.
Consider the nonparametric regression model
, whereg is an unknown function to be estimated on [0, 1],
are the fixed design points in the interval [0, 1] and
is a triangular array of row iid random variables having median zero. The nearest neighbor median estimator
is taken as the estimator of the unknown functiong(x). Median cross validation (mev) criterion is employed to select the smoothing parameterh. Leth
π
*
be the smoothing parameter chosen by mev criterion. Under mild regularity conditions, the upper and lower bounds ofh
π
*
, the rate of convergence and the weak consistency of the median cross-validated estimate
are obtained.
Project supported by the National Natural Science Foundation of China and the Doctoral Foundation of Education of China. 相似文献
7.
Zhi-Wei Sun 《Israel Journal of Mathematics》2002,128(1):135-156
In this paper we study [
r
n
]
m
=Σ
k≡r(modm) (
k
n
) wherem>0,n≥0 andr are integers. We show that [
r
n
]
m
(m>2) can be expressed in terms of some linearly recurrent sequences with orders not exceeding ϕ(m)/2. In particular, we determine [
r
n
]
12
explicitly in terms of first order and second order recurrences. It follows that for any primep>3 we have
and
.
The research is supported by the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions
of MOE, and the National Natural Science Foundation of P. R. China. 相似文献
8.
Isotropic bodies and Bourgain''''s problem 总被引:1,自引:0,他引:1
HE Binwu & LENG Gangsong Department of Mathematics Shanghai University Shanghai China 《中国科学A辑(英文版)》2005,48(5):666-679
Let K (?) Rn be a convex body of volume 1 whose barycenter is at the origin, LK be the isotropic constant of K. Finding the least upper bound of LK , being called Bourgain's problem, is a well known open problem in the local theory of Banach space. The best estimate known today is LK < cn1/4 log n, recently shown by Bourgain, for an arbitrary convex body in any finite dimension. Utilizing the method of spherical section function, it is proven that if K is a convex body with volume 1 and r1Bn2 (?) K (?) r2Bn2,(r1≥1/2, r2≤(?)/2), then (?) ≤(?) and find the conditions with equality. Further, the geometric characteristic of isotropic bodies is shown. 相似文献
9.
Let {X
n
; n ≥ 1} be a sequence of independent and identically distributed U[0,1]-distributed random variables. Define the uniform empirical process $F_n (t) = n^{ - \tfrac{1}
{2}} \sum\nolimits_{i = 1}^n {(I_{\{ X_i \leqslant t\} } - t),0} \leqslant t \leqslant 1,\left\| {F_n } \right\| = \sup _{0 \leqslant t \leqslant 1} \left| {F_n (t)} \right|
$F_n (t) = n^{ - \tfrac{1}
{2}} \sum\nolimits_{i = 1}^n {(I_{\{ X_i \leqslant t\} } - t),0} \leqslant t \leqslant 1,\left\| {F_n } \right\| = \sup _{0 \leqslant t \leqslant 1} \left| {F_n (t)} \right|
. In this paper, the exact convergence rates of a general law of weighted infinite series of E {‖F
n
‖ − ɛg
s
(n)}+ are obtained. 相似文献
10.
Characterization of Compact Support of Fourier Transform for Orthonormal Wavelets of L^2(R^d) 总被引:1,自引:0,他引:1
Zhi Hua Zhang 《数学学报(英文版)》2005,21(4):855-864
Let{ψμ} be an orthonormal wavelet of L^2(R^d) and the support of a whole of its Fourier transform be Uμsupp{ψμ}=Пi=1^d[Ai, Di]-Пi=1^d(Bi, Ci), Ai≤Bi≤Ci≤Di. Under the weakest condition that each │ψμ│, is continuous for ω ∈ δ(Пi=1^d[Ai, Di]), a characterization of the above support of a whole is given. 相似文献
11.
Li Xin Zhang 《数学学报(英文版)》2008,24(4):631-646
Let X, X1, X2,... be i.i.d, random variables with mean zero and positive, finite variance σ^2, and set Sn = X1 +... + Xn, n≥1. The author proves that, if EX^2I{|X|≥t} = 0((log log t)^-1) as t→∞, then for any a〉-1 and b〉 -1,lim ε↑1/√1+a(1/√1+a-ε)b+1 ∑n=1^∞(logn)^a(loglogn)^b/nP{max κ≤n|Sκ|≤√σ^2π^2n/8loglogn(ε+an)}=4/π(1/2(1+a)^3/2)^b+1 Г(b+1),whenever an = o(1/log log n). The author obtains the sufficient and necessary conditions for this kind of results to hold. 相似文献
12.
Qingfeng Sun 《Central European Journal of Mathematics》2011,9(2):328-337
Let λ(n) be the Liouville function. We find a nontrivial upper bound for the sum
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