共查询到20条相似文献,搜索用时 31 毫秒
1.
Charles J. Colbourn Dean G. Hoffman Kevin T. Phelps Vojtěch Rödl Peter M. Winkler 《Combinatorica》1991,11(3):207-218
We prove that the number oft-wise balanced designs of ordern is asymptotically
, provided that blocks of sizet are permitted. In the process, we prove that the number oft-profiles (multisets of block sizes) is bounded below by
and above by
for constants c2>c1>0. 相似文献
2.
Zeng Guangxing 《中国科学A辑(英文版)》1999,42(3):272-280
For an ordered field (K,T) and an idealI of the polynomial ring
, the construction of the generalized real radical
ofI is investigated. When (K,T) satisfies some computational requirements, a method of computing
is presented.
Project supported by the National Natural Science Foundation of China (Grant No. 19661002) and the Climbing Project. 相似文献
3.
We study Galilei groups represented as groups of Lie transformations in the space of two independent variables and one dependent
variable. We classify the representations of the groupsAG
1 (1, 1),A G
2 (1,1),A G
3 (1,1),
,
, and
in the class of Lie vector fields.
Deceased.
Institute of Mathematics, Ukrainian Academy of Sciences, Kiev. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50,
No. 3, pp. 414–423, March, 1998. 相似文献
4.
R. E. Maiboroda 《Ukrainian Mathematical Journal》1998,50(7):1067-1079
For a process X(t)=Σ
j=1
M
g
j
(t)ξ
j
(), where gj(t) are nonrandom given functions, is a stationary vector-valued Gaussian process, Eξk(t) = 0, and Eξk(0) Eξl(τ) = r
kl(τ), we construct an estimate for the functions r
kl(τ) on the basis of observations X(t), t ∈ [0, T]. We establish conditions for the asymptotic normality of as T → ∞. We consider the problem of the optimal choice of parameters of the estimate depending on observations.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 7, pp. 937–947, July, 1998. 相似文献
5.
It is proved that (i) for
survives to E∞; (ii) for
survives to E∞.
Project supported by the Doctoral Program Foundation of China. 相似文献
6.
I. K. Matsak 《Ukrainian Mathematical Journal》1998,50(10):1551-1558
Under additional conditions on a bounded normally distributed random function X = X(
t), t ∈ T, we establish a relation of the form
where are independent copies of , and (a
n) and (b
n) are numerical sequences.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 10, pp. 1359–1365, October, 1998. 相似文献
7.
Helena Ferreira 《Extremes》2000,3(4):385-392
Let
be a sequence of identically distributed variables. We study the asymptotic distribution of
, where Y
[r:n] denotes the concomitant of the rth order statistic X
r:n
, corresponding to
, and
is held fixed while
. Conditions are given for the
and
to have the same asymptotic behavior as that we would apply if
were i.i.d. The result is illustrated with a simple linear regression model
, where
is a stationary sequence with extremal index
. 相似文献
8.
Zhengyan Lin 《中国科学A辑(英文版)》1997,40(4):337-349
Let
be a sequence of independent Gaussian processes with (h)
Put
. The large increments forY(·) with bounded σ(p, h) are investigated. As an example the large increments of infinite-dimensional fractional Ornstein-Uhlenbeck process in IP are given. The method can also be applied to certain processes with stationary increments.
Project supported by the National Natural Science Foundation of China and the Natural Science Foundation of Zhejiang Province. 相似文献
9.
Di Zhao 《中国科学A辑(英文版)》1999,42(9):897-904
LetM be a compact Riemann manifold with the Ricci curvature ≽ - R(R = const. > 0) . Denote by d the diameter ofM. Then the first eigenvalue λ1 ofM satisfies
. Moreover if
, then
相似文献
10.
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
11.
Zhu Yaochen 《数学学报(英文版)》1988,4(4):364-371
Let
be a finitely generated extension field of ℚ, andα
i,βj(1⩽i⩽m,1⩽j⩽n) be some complex numbers. Let
(k=1,2,3) be fields obtained by adjoining to
the numbers {α
i,βj exp(αiβj)}, {αi, exp(αiβj)}, and {exp(αiβj)}, respectively. In the present note the relation between the transcendental degree of
over
and the transcendence type of
over ℚ is given.
This work was completed in Dpt. Math., Univ. of Southern Mississippi, Hattiesburg, USA. 相似文献
12.
Andrew J. Sommese 《Milan Journal of Mathematics》1997,67(1):49-75
Let
be an algebraic submanifold of complex projective space ℙ
N
. Assume thatn:=dim
and let
denote the restriction of the hyperplane section bundle
to
. The meromorphic map
associated to
fork≥1 ties together the pluricanonical maps of the surface sections of
. Known results show that the behavior of
is far better than one would expect from experience with the pluricanonical mappings of algebraic surfaces. In this article
we discuss the known results on the structure of the mappings
and describe the open problems.
Conferenza tenuta il 5 giugno 1997 相似文献
13.
14.
XuSenlin DengQintao ChenDongmei 《分析论及其应用》2004,20(3):288-293
Let M be a compact minimal hypersurface of sphere Sn 1(1). Let (M) be H (r)-torus of sphere Sn 1 (1).Assume they have the same constant mean curvature H, the result in [1] is that ifSpec0(M, g) =Spec0((M), g),then for 3≤ n ≤ 6, r2≤n-1/n or n ≥ 6, r2 ≥ n-1, then M is isometric to (M). We improved the result and prove that: if Spec0(M,g) =Spec0((M),g), then M is isometric to (M). Generally, if Specp(M,g) =Specp((M),g), here p is fixed and satisfies that n(n - 1) ≠ 6p(n - p), then M is isometric to (M). 相似文献
15.
Lutz Strüngmann 《Israel Journal of Mathematics》2006,151(1):29-51
LetR be a unital associative ring and
two classes of leftR-modules. In [St3] the notion of a (
) pair was introduced. In analogy to classical cotorsion pairs, a pair (V,W) of subclasses
is called a (
) pair if it is maximal with respect to the classes
and the condition Ext
R
1
(V, W)=0 for all
. In this paper we study
pairs whereR = ℤ and
is the class of all torsion-free abelian groups andT is the class of all torsion abelian groups. A complete characterization is obtained assumingV=L. For example, it is shown that every
pair is singly cognerated underV=L.
The author was supported by a DFG grant. 相似文献
16.
Jacob Korevaar 《Journal d'Analyse Mathématique》2001,85(1):177-194
For entire functionsf whose power series have Hadamard gaps with ratio ≥1+α>1, Gaier has shown that the condition |f(x)|≤e
x forx≥0 implies |f(z)|≤C
αe|z| (*) for allz. Here the result is extended to the case of square root gaps, that is,
, with
, where α>0. Smaller gaps cannot work. In connection with his proof of the general high indices theorem for Borel summability,
Gaier had shown that square root gaps imply
. Having such an estimate, one can adapt Pitt’s Tauberian method for the restricted Borel high indices theorem to show that,
in fact,
, which implies (*). The author also states an equivalent distance formula involving monomialsx
pke−xinL
∞ (0, ∞). 相似文献
17.
A. N. Skiba 《Mathematical Notes》1999,65(3):326-330
It is proved that, if
is a singly generated composition formation, where
, then
is a composition formation.
Translated fromMatematicheskie Zametki, Vol. 65, No. 3, pp. 389–395, March, 1999. 相似文献
18.
K. I. Beidar M. Bre@scaron;ar M. A. Chebotar 《Journal of Mathematical Sciences》2000,102(6):4557-4565
Let
, be the algebra of upper triangular r×r matrices over field aF. We describe multilinear maps
, where n≤r, such that [f(A,...,A), A]=0 for all
, provided that |F| >n + 1. As an application of the results obtained, we describe linear automorphisms θ of
such that [θ(A2), θ(A)]=0 for all
.
Translated from Itogi Nauki i Tekhniki, Seriya Sovremennaya Matematika i Ee Prilozheniya. Tematicheskie Obzory. Vol. 74, Algebra-15,
2000. 相似文献
19.
Jugal Ghorai 《Annals of the Institute of Statistical Mathematics》1980,32(1):341-350
LetX
1,...,X
n
be i.i.d. random variable with a common densityf. Let
be an estimate off(x) based on a complete orthonormal basis {φ
k
:k≧0} ofL
2[a, b]. A Martingale central limit theorem is used to show that
, where
and
. 相似文献
20.
We study the boundary-value problemu
tt
-u
xx
=g(x, t),u(0,t) =u (π,t) = 0,u(x, t +T) =u(x, t), 0 ≤x ≤ π,t ∈ ℝ. We findexact classical solutions of this problem in three Vejvoda-Shtedry spaces, namely, in the classes of, and-periodic functions (q and s are natural numbers). We obtain the results only for sets of periods, and which characterize the classes of π-, 2π -, and 4π-periodic functions.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 51, No. 2, pp. 281–284, February, 1999. 相似文献