共查询到20条相似文献,搜索用时 671 毫秒
1.
Enrico Jabara 《Rendiconti del Circolo Matematico di Palermo》2001,50(3):393-404
LetG be a group and α an automorphism ofG; α is calledn-splitting if
for allg∈G. In this note we study the structure of finite groups admitting an-splitting automorphism of order 2.
相似文献
2.
Enrico Jabara 《Rendiconti del Circolo Matematico di Palermo》1996,45(1):84-92
LetG be a group admitting a 4-splitting automorphism (i.e. an automorphism σ such that
for everyg∈G). In this paper we prove that ifG≠1 is solvable with derived lengthd thenG′ is nilpotent of class not greater than (4
d−1−1)/3. 相似文献
3.
Zoé Chatzidakis 《Israel Journal of Mathematics》1986,55(2):173-183
LetK be a hilbertian field,G(K) its absolute Galois group. IfK is countable, then for a.a.
inG(K)
e
,
and there is no intermediate field
with
. Let
∈G(K)
e
. Then for a.a.
in
. 相似文献
4.
V. V. Andrievskii 《Journal d'Analyse Mathématique》2005,96(1):283-295
LetG⊂C be a quasidisk,K ⊂ G be a compact set, andp
n be a non-constant complex polynomial of degree at mostn. We establish the inequality
whereα
n < 0 depends onn, K,
and the geometrical structure of ϖG. 相似文献
5.
Mohd Salmi Md. Noorani William Parry 《Bulletin of the Brazilian Mathematical Society》1992,23(1-2):137-151
We derive a Chebotarev Theorem for finite homogeneous extensions of shifts of finite type. These extensions are of the form
:X×G/H→X×G/H where
(x,gH)=(σx, α(x)gH), for some finite groupG and subgroupH. Given a σ-closed orbit τ, the periods of the
-closed orbits covering τ define a partition of the integer |G/H|. The theorem then gives us an asymptotic formula for the number of closed orbits with respect to the various partitions
of the integer |G/H|. We apply our theorem to the case of a finite extension and of an automorphism extension of shifts of finite type. We also
give a further application to ‘automorphism extensions’ of hyperbolic toral automorphisms.
Financially supported by Universiti Kebangsaan Malaysia 相似文献
6.
Let {X, X
n;n≥1} be a strictly stationary sequence of ρ-mixing random variables with mean zero and finite variance. Set
. Suppose lim
n→∞
and
, where d=2, if −1<b<0 and d>2(b+1), if b≥0. It is proved that, for any b>−1,
, where Γ(•) is a Gamma function.
Research supported by the National Natural Science Foundation of China (10071072). 相似文献
7.
The solvability in anisotropic spaces
, σ ∈ ℝ+, p, q ∈ (1, ∞), of the heat equation ut − Δu = f in ΩT ≡ (0, T) × Ω is studied under the boundary and initial conditions u = g on ST, u|t=0 = u0 in Ω, where S is the boundary of a bounded domain Ω ⊂ ℝn. The existence of a unique solution
of the above problem is proved under the assumptions that
and under some additional conditions on the data. The existence is proved by the technique of regularizers. For this purpose
the local-in-space solvability near the boundary and near an interior point of Ω is needed. To show the local-in-space existence,
the definition of Besov spaces by the dyadic decomposition of a partition of unity is used. This enables us to get an appropriate
estimate in a new and promising way without applying either the potential technique or the resolvent estimates or the interpolation.
Bibliography: 26 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 348, 2007, pp. 40–97. 相似文献
8.
I. E. Zuber 《Vestnik St. Petersburg University: Mathematics》2010,43(3):139-142
A control of an nth-order discrete system under an external perturbation is considered. The elements of the matrix of the system are functionals
of any nature. The observation matrix is constant and has arbitrary size m × n. A control ensuring the independence of the output σ
k
on the external perturbation ψ
k
is synthesized; moreover,
$
\sigma _{k + 1} = \beta \sigma _k , 0 < \beta < 1, \sigma _k \in \mathbb{R}^m
$
\sigma _{k + 1} = \beta \sigma _k , 0 < \beta < 1, \sigma _k \in \mathbb{R}^m
相似文献
9.
We study the irrational factor function I(n) introduced by Atanassov and defined by , where is the prime factorization of n. We show that the sequence {G(n)/n}
n≧1, where G(n) = Π
ν=1
n
I(ν)1/n
, is convergent; this answers a question of Panaitopol. We also establish asymptotic formulas for averages of the function
I(n).
Research of the third author is supported in part by NSF grant number DMS-0456615. 相似文献
10.
Kôichi Inada 《Annals of the Institute of Statistical Mathematics》1984,36(1):207-215
Summary This paper considers the problem of estimating a normal mean from the point of view of the estimation after preliminary test
of significance. But our point of view is different from the usual one. The difference is interpretation about a null hypothesis.
Let
denote the sample mean based on a sample of sizen from a normal population with unknown mean μ and known varianceσ
2. We consider the estimator that assumes the value
when
and the value
when
where ω is a real number such that 0≤ω≤1 andC is some positive constant. We prove the existence of ω, satisfying the minimax regret criterion and make a numerical comparison
among estimators by using the mean square error as a criterion of goodness of estimators. 相似文献
11.
Let G be a multigraph. The star number s(G) of G is the minimum number of stars needed to decompose the edges of G. The star arboricity sa(G) of G is the minimum number of star forests needed to decompose the edges of G. As usual λK
n
denote the λ-fold complete graph on n vertices (i.e., the multigraph on n vertices such that there are λ edges between every pair of vertices). In this paper, we prove that for n ⩾ 2
12.
Volker Turau 《Israel Journal of Mathematics》1988,62(2):206-212
For a finite groupG and some prime powerp
n
, the
-subgroup
is defined by
. Meixner proved that ifG is a finite solvable group and
for somen≧1, then the Fitting length of
is bounded by 4n. In the following note it is shown that the 2-length of
is at mostn. This result cannot be derived from Meixner’s paper, since his result implies only that the 2-length is bounded by 2n. 相似文献
13.
Summary Let
be a sequence of independent identically distributed random variables withθ
1∼G and the conditional distribution ofx
1 givenθ
1=θ given by
. HereG is unknown andF
θ(·) is known. This paper provides estimators
ofG based onx
1, …,x
n such that the random variable sup
has an asymptotic distribution asn→∞ under certain on conditionsG and for certain choices ofF
θ. A simulation model has been discussed involving the uniform distribution on (0, θ) forF
θ and an exponential distribution forG.
Research supported by the National Science Foundation under Grant #MCS77-26809. 相似文献
14.
Let M
n
= X
1 + ⋯ + X
n
be a sum of independent random variables such that X
k
⩽ 1,
and EX
k
2
= σ
k
2
for all k. Hoeffding [15, Theorem 3] proved that
15.
Precise Rates in the Law of Iterated Logarithm for the Moment of I.I.D. Random Variables 总被引:1,自引:0,他引:1
Ye JIANG Li Xin ZHANG 《数学学报(英文版)》2006,22(3):781-792
Let{X,Xn;n≥1} be a sequence of i,i.d, random variables, E X = 0, E X^2 = σ^2 〈 ∞.Set Sn=X1+X2+…+Xn,Mn=max k≤n│Sk│,n≥1.Let an=O(1/loglogn).In this paper,we prove that,for b〉-1,lim ε→0 →^2(b+1)∑n=1^∞ (loglogn)^b/nlogn n^1/2 E{Mn-σ(ε+an)√2nloglogn}+σ2^-b/(b+1)(2b+3)E│N│^2b+3∑k=0^∞ (-1)k/(2k+1)^2b+3 holds if and only if EX=0 and EX^2=σ^2〈∞. 相似文献
16.
We observe an unknown function of infinitely many variables f = f(t), t = (t1, ..., tn, ... ) ∈, [0, 1]∞, in the Gaussian white noise of level ε > 0. We suppose that in each variable there exists a 1-periodical σ-smooth extension
of the function f(t) to IR
∞. Taking a quantity σ > 0 and a positive sequence a = {ak}, we consider the set
that consists of functions f such that
. We consider the cases ak = kα and ak = exp(λk), α > 0, λ > 0. We would like to estimate a function f ∈
or to test the null hypothesis H0: f = 0 against the alternatives f ∈
, where the set
consists of functions f ∈
such that ∥f∥2 ≥ r. In the estimation problem, we obtain the asymptotics (as ε → 0) of the minimax quadratic risk. In the detection problem,
we study the sharp asymptotics of minimax separation rates f
ɛ
*
that provide distiguishability in the problems. Bibliography: 12 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 328, 2005, pp. 91–113. 相似文献
17.
V. M. Dil’nyi 《Ukrainian Mathematical Journal》2006,58(9):1425-1432
Let G ∈ H
σ
p
(ℂ+), where H
σ
p
(ℂ+) is the class of functions analytic in the half plane ℂ+ = {z: Re z > 0} and such that
18.
Let (X, Xn; n ≥1) be a sequence of i.i.d, random variables taking values in a real separable Hilbert space (H, ||·||) with covariance operator ∑. Set Sn = X1 + X2 + ... + Xn, n≥ 1. We prove that, for b 〉 -1,
lim ε→0 ε^2(b+1) ∞ ∑n=1 (logn)^b/n^3/2 E{||Sn||-σε√nlogn}=σ^-2(b+1)/(2b+3)(b+1) B||Y|^2b+3 holds if EX=0,and E||X||^2(log||x||)^3bv(b+4)〈∞ where Y is a Gaussian random variable taking value in a real separable Hilbert space with mean zero and covariance operator ∑, and σ^2 denotes the largest eigenvalue of ∑. 相似文献 19.
Claude Tardif 《Combinatorica》2005,25(5):625-632
We prove that the identity
20.
LetX andY denote two complex Banach spaces and letB(Y, X) denote the algebra of all bounded linear operators fromY toX. ForA∈B(X)
n
,B∈B(Y)
n
, the elementary operator acting onB(Y, X) is defined by
. In this paper we obtain the formulae of the spectrum and the essential spectrum of Δ(A, B) by using spectral mapping theorems. Forn=1, we prove thatS
p
(L
A
,R
B
)=σ(A)×σ(B) and
. 相似文献
|