共查询到20条相似文献,搜索用时 31 毫秒
1.
Qi Keng LU Ke WU 《数学学报(英文版)》2007,23(4):577-598
For an integer m ≥ 4, we define a set of 2[m/2] × 2[m/2] matrices γj (m), (j = 0, 1,..., m - 1) which satisfy γj (m)γk (m) +γk (m)γj (m) = 2ηjk (m)I[m/2], where (ηjk (m)) 0≤j,k≤m-1 is a diagonal matrix, the first diagonal element of which is 1 and the others are -1, I[m/2] is a 2[m/1] × 2[m/2] identity matrix with [m/2] being the integer part of m/2. For m = 4 and 5, the representation (m) of the Lorentz Spin group is known. For m≥ 6, we prove that (i) when m = 2n, (n ≥ 3), (m) is the group generated by the set of matrices {T|T=1/√ξ((I+k) 0 + 0 I-K) ( U 0 0 U), (ii) when m = 2n + 1 (n≥ 3), (m) is generated by the set of matrices {T|T=1/√ξ(I -k^- k I)U,U∈ (m-1),ξ=1-m-2 ∑k,j=0 ηkja^k a^j〉0, K=i[m-3 ∑j=0 a^j γj(m-2)+a^(m-2) In],K^-=i[m-3∑j=0 a^j γj(m-2)-a^(m-2) In]} 相似文献
2.
Piotr Niemiec 《Rendiconti del Circolo Matematico di Palermo》2008,57(3):391-399
The aim of the paper is to prove that every f ∈ L
1([0,1]) is of the form f = , where j
n,k
is the characteristic function of the interval [k- 1 / 2
n
, k / 2
n
) and Σ
n=0∞Σ
k=12n
|a
n,k
| is arbitrarily close to ||f|| (Theorem 2). It is also shown that if μ is any probabilistic Borel measure on [0,1], then for any ɛ > 0 there exists a sequence (b
n,k
)
n≧0
k=1,...,2n
of real numbers such that and for each Lipschitz function g: [0,1] → ℝ (Theorem 3).
相似文献
3.
Michel WEBER 《数学学报(英文版)》2006,22(2):377-382
Let D be an increasing sequence of positive integers, and consider the divisor functions:
d(n, D) =∑d|n,d∈D,d≤√n1, d2(n,D)=∑[d,δ]|n,d,δ∈D,[d,δ]≤√n1,
where [d,δ]=1.c.m.(d,δ). A probabilistic argument is introduced to evaluate the series ∑n=1^∞and(n,D) and ∑n=1^∞and2(n,D). 相似文献
4.
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
5.
We prove a functional large deviations principle for the family of random functions
, where { Zt, t ∈, [0, 1]} is a real-valued centered Gaussian process. Bibliography: 19 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 328, 2005, pp. 169–181. 相似文献
6.
De Li LI Andrew ROSALSKY Andrei VOLODIN 《数学学报(英文版)》2007,23(4):599-612
For a sequence of i.i.d. Banach space-valued random variables {Xn; n ≥ 1} and a sequence of positive constants {an; n ≥ 1}, the relationship between the Baum-Katz-Spitzer complete convergence theorem and the law of the iterated logarithm is investigated. Sets of conditions are provided under which
(i) lim sup n→∞ ||Sn||/an〈∞ a.s.and
∞ ∑n=1(1/n)P(||Sn||/an ≥ε〈∞for all ε 〉 λ for some constant λ ∈ [0, ∞) are equivalent;
(ii) For all constants λ ∈ [0, ∞),
lim sup ||Sn||/an =λ a.s.and ^∞∑ n=1(1/n) P(||Sn||/an ≥ε){〈∞, if ε〉λ =∞,if ε〈λare equivalent. In general, no geometric conditions are imposed on the underlying Banach space. Corollaries are presented and new results are obtained even in the case of real-valued random variables. 相似文献
7.
Thierry Horsin Molinaro 《manuscripta mathematica》1993,78(1):317-333
This paper is concerned with the evolution of harmonic maps from an open set Ω of ℝm into an n-dimensionnal ellipsoid
where a ∈ (0, 1]
We prove the existence of a smooth solution of the equation of evolution of harmonic maps if the initial data lies in a compact
subset of the upper hemisphere of an ellispoid. 相似文献
8.
By J. Steuding 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2001,71(1):113-121
We consider the value distribution of Hurwitz zeta-functions
at the nontrivial zeros ϱ= β + iγ of the Riemann zeta-function ζ (s):= ζ (s, 1). Using the method of Conrey, Ghosh and Gonek we prove for fixed 0< α< 1 andH ≤T that
with some absolute constantC > 0 (a similar result was first proved by Fujii [4] under assumption of the Riemann hypothesis). It follows that
is an entire function if and only if α = 1/2 or α = l. Further, we prove for α ≠ 1/2, 1 the existence of zeros ϱ = β +iγ withT < γ ≤T + T3/4, 1/2 β ≤ 9/10+ ε and ζ(ϱ,α)≠0. 相似文献
9.
We prove that if f belongs to the Morrey space
, with λ ∊ [0, n−2], and u is the solution of the problem
then Du belongs to the space
, for any
Mathematics Subject Classification (2000) 35J25, 35D10 相似文献
10.
For an l-graph
, the Turán number
is the maximum number of edges in an n-vertex l-graph
containing no copy of
. The limit
is known to exist [8]. The Ramsey–Turán density
is defined similarly to
except that we restrict to only those
with independence number o(n). A result of Erdős and Sós [3] states that
as long as for every edge E of
there is another edge E′of
for which |E∩E′|≥2. Therefore a natural question is whether there exists
for which
.
Another variant
proposed in [3] requires the stronger condition that every set of vertices of
of size at least εn (0<ε<1) has density bounded below by some threshold. By definition,
for every
. However, even
is not known for very many l-graphs
when l>2.
We prove the existence of a phenomenon similar to supersaturation for Turán problems for hypergraphs. As a consequence, we
construct, for each l≥3, infinitely many l-graphs
for which
.
We also prove that the 3-graph
with triples 12a, 12b, 12c, 13a, 13b, 13c, 23a, 23b, 23c, abc, satisfies
. The existence of a hypergraph
satisfying
was conjectured by Erdős and Sós [3], proved by Frankl and R?dl [6], and later by Sidorenko [14]. Our short proof is based
on different ideas and is simpler than these earlier proofs.
* Research supported in part by the National Science Foundation under grants DMS-9970325 and DMS-0400812, and an Alfred P.
Sloan Research Fellowship.
† Research supported in part by the National Science Foundation under grants DMS-0071261 and DMS-0300529. 相似文献
11.
T. M. Chan 《Discrete and Computational Geometry》1996,16(4):369-387
We use known data structures for ray-shooting and linear-programming queries to derive new output-sensitive results on convex
hulls, extreme points, and related problems. We show that thef-face convex hull of ann-point setP in a fixed dimensiond≥2 can be constructed in
time; this is optimal if
for some sufficiently large constantK. We also show that theh extreme points ofP can be computed in
time. These results are then applied to produce an algorithm that computes the vertices of all the convex layers ofP inO(n
2−γ) time for any constant
. Finally, we obtain improved time bounds for other problems including levels in arrangements and linear programming with
few violated constraints. In all of our algorithms the input is assumed to be in general position.
This research was supported by a Killam Predoctoral Fellowship and an NSERC Postgraduate Scholarship. 相似文献
12.
We study pairs of Dirichlet series
and
in whicha(n) counts the number of objects of “size”n of some class of objects which is closed under formation of direct products and extraction of irreducible factors, andp(n) counts the number of objects of “size”n which are irreducible in this class. We prove Dirichlet series analogues of certain results about power series and use these
results to prove some conjectures of Burris concerning first-order 0–1 laws. 相似文献
13.
Let u = (u
n
) be a sequence of real numbers whose generator sequence is Cesàro summable to a finite number. We prove that (u
n
) is slowly oscillating if the sequence of Cesàro means of (ω
n
(m−1)(u)) is increasing and the following two conditions are hold:
$\begin{gathered}
\left( {\lambda - 1} \right)\mathop {\lim \sup }\limits_n \left( {\frac{1}
{{\left[ {\lambda n} \right] - n}}\sum\limits_{k = n + 1}^{\left[ {\lambda n} \right]} {\left( {\omega _k^{\left( m \right)} \left( u \right)} \right)^q } } \right)^{\frac{1}
{q}} = o\left( 1 \right), \lambda \to 1^ + , q > 1, \hfill \\
\left( {1 - \lambda } \right)\mathop {\lim \sup }\limits_n \left( {\frac{1}
{{n - \left[ {\lambda n} \right]}}\sum\limits_{k = \left[ {\lambda n} \right] + 1}^n {\left( {\omega _k^{\left( m \right)} \left( u \right)} \right)^q } } \right)^{\frac{1}
{q}} = o\left( 1 \right), \lambda \to 1^ - , q > 1, \hfill \\
\end{gathered}$\begin{gathered}
\left( {\lambda - 1} \right)\mathop {\lim \sup }\limits_n \left( {\frac{1}
{{\left[ {\lambda n} \right] - n}}\sum\limits_{k = n + 1}^{\left[ {\lambda n} \right]} {\left( {\omega _k^{\left( m \right)} \left( u \right)} \right)^q } } \right)^{\frac{1}
{q}} = o\left( 1 \right), \lambda \to 1^ + , q > 1, \hfill \\
\left( {1 - \lambda } \right)\mathop {\lim \sup }\limits_n \left( {\frac{1}
{{n - \left[ {\lambda n} \right]}}\sum\limits_{k = \left[ {\lambda n} \right] + 1}^n {\left( {\omega _k^{\left( m \right)} \left( u \right)} \right)^q } } \right)^{\frac{1}
{q}} = o\left( 1 \right), \lambda \to 1^ - , q > 1, \hfill \\
\end{gathered} 相似文献
14.
We prove a time hierarchy theorem for inverting functions computable in a slightly nonuniform polynomial time. In particular,
we prove that if there is a strongly one-way function, then for any k and for any polynomial p, there is a function f computable in linear time with one bit of advice such that there is a polynomial-time probabilistic adversary that inverts
f with probability ≥ 1/p(n) on infinitely many lengths of input, while all probabilistic O(n
k
)-time adversaries with logarithmic advice invert f with probability less than 1/p(n) on almost all lengths of input. We also prove a similar theorem in the worst-case setting, i.e., if P ≠ NP, then for every l > k ≥ 1
15.
Let n and r be positive integers. Suppose that a family
satisfies F1∩···∩Fr ≠∅ for all F1, . . .,Fr ∈
and
. We prove that there exists ε=ε(r) >0 such that
holds for 1/2≤w≤1/2+ε if r≥13. 相似文献
16.
S. BERHANU F. CUCCU G. PORRU 《数学学报(英文版)》2007,23(3):479-486
For γ≥1 we consider the solution u=u(x) of the Dirichlet boundary value problem Δu + u^-γ=0 in Ω, u=0 on δΩ. For γ= 1 we find the estimate
u(x)=p(δ(x))[1+A(x)(log 1/δ(x)^-6],
where p(r) ≈ r r√2 log(1/r) near r = 0,δ(x) denotes the distance from x to δΩ, 0 〈ε 〈 1/2, and A(x) is a bounded function. For 1 〈 γ 〈 3 we find
u(x)=(γ+1/√2(γ-1)δ(x))^2/γ+[1+A(x)(δ(x))2γ-1/γ+1]
For γ3= we prove that
u(x)=(2δ(x))^1/2[1+A(x)δ(x)log 1/δ(x)] 相似文献
17.
Chen Hua 《数学学报(英文版)》1997,13(1):81-89
In this paper, we study the asymptotic behaviour of the scattering phases(λ) of the Dirichlet Laplacian associated with obstacle
, where Ω is a bounded open subset of ℝ
n
(n≥2) with non-smooth boundary ∂Ω and connected complement Ω
e
=ℝ
n
. We can prove that if Ω satisfies a certain geometrical condition, then
18.
Let G and H be Lie groups with Lie algebras
and
. Let G be connected. We prove that a Lie algebra homomorphism
is exact if and only if it is completely positive. The main resource is a corresponding theorem about representations on
Hilbert spaces.
This article summarizes the main results of [1].
Received: 6 December 2005 相似文献
19.
In this paper, we prove that
and round geodesic spheres are the only n-dimensional compact embedded rotation hypersurfaces with Hm = 0 (1 ≤ m ≤ n − 1) in a unit sphere Sn+1(1). When m = 1, our result reduces to the result of T. Otsuki [O1], [O2], Brito and Leite [BL].
The project is supported by the grant No. 10531090 of NSFC. 相似文献
20.
Henrik Petersson 《Integral Equations and Operator Theory》2007,57(3):413-423
We prove that for any weighted backward shift B = Bw on an infinite dimensional separable Hilbert space H whose weight sequence w = (wn) satisfies
, the conjugate operator
is hypercyclic on the space S(H) of self-adjoint operators on H provided with the topology of uniform convergence on compact sets. That is, there exists an
such that
is dense in S(H). We generalize the result to more general conjugate maps
, and establish similar results for other operator classes in the algebra B(H) of bounded operators, such as the ideals K(H) and N(H) of compact and nuclear operators respectively. 相似文献
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