共查询到20条相似文献,搜索用时 31 毫秒
1.
Ishay Weissman 《Probability Theory and Related Fields》1976,37(1):35-41
Let be an Euclidean space; Y
n
, Z, U random vectors in ; h
n
, g
n
affine transformations and let þ be a subgroup of the group G of all the in vertible affine transformations, closed relative to G. Suppose that gn
and
where Z is nonsingular. The behaviour of
n
= h
n
g
n
–1
as n is discussed first. The results are used then to prove that if
for all t(0, ), where h
n
þ and Z
1 is nonsingular and nonsymmetric with respect to þ then
H,
for all t(0,) and is a continuous homomorphism of the multiplicative group of (0, ) into þ. The explicit forms of the possible are shown. 相似文献
2.
Subdifferentials with respect to dualities 总被引:1,自引:0,他引:1
Juan-Enrique Martinez-Legaz Ivan Singer 《Mathematical Methods of Operations Research》1995,42(1):109-125
LetX andW be two sets and: ¯RX ¯RW a duality (i.e., a mapping
such that
for all
and all index setsI). We introduce and study the subdifferential
of a function
at a pointx
o
X, with respect to. We also consider the particular cases when is a (Fenchel-Moreau) conjugation, or a -duality, or a -duality, in the sense of [8]. 相似文献
3.
ATSUSHI NOMA 《Compositio Mathematica》1997,106(1):61-70
For a smooth projective variety X of dimension n in a projective space
defined over an algebraically closed field k, the Gauss mapis a morphism from X to the Grassmannian of n-plans in
sending
to the embedded tangent space
.The purpose of this paper is to prove the generic injectivity of Gauss mapsin positive characteristic for two cases; (1) weighted complete intersectionsof dimension
of general type; (2) surfaces or 3-folds with -semistable tangent bundles; based on a criterion of Kaji by looking atthe stability of Frobenius pull-backs of their tangent bundles. The first result implies that a conjecture of Kleiman--Piene is true in case X is of general type of dimension
. The second result is a generalization of the injectivity for curves. 相似文献
4.
Aparna W. Higgins 《Algebra Universalis》1985,20(2):179-193
Given a group G and a descending chainG
0,G
1,...,G
n, of normal subgroups ofG, we prove that there exists a universal algebra
, such that the chain ...Wn(
)...W1(
}) W0(
)W(
) is isomorphic to the chain ...G
n ...G
1G
0G, where W(
) is the group of weak automorphisms of
, and Wn(
) is the group of weak automorphisms of
that leaves alln-ary operations fixed.We also prove that there are an infinite number of non-isomorphic algebras that satisfy the above.These results are a generalization of those proved by J. Sichler, in the special case when G=G0, and G1=G2=...=Gn=....Presented by J. Mycielski.This paper comprises part of the author's doctoral dissertation at the University of Notre Dame in 1983. The author wishes to express her deep gratitude to Professor Abraham Goetz for suggesting this problem, for being extremely generous with his time and experience, and for giving her his constant encouragement. The author also thanks the reviewer for his helpful comments. 相似文献
5.
Jean-Pierre Kahane Jacques Peyrière Wen Zhi-ying Wu Li-ming 《Probability Theory and Related Fields》1988,79(4):625-628
Summary Let be a bounded function on such that
converges towards l as n goes to infinity, uniformly with respect to m. Let {X
n} be a random walk on , not concentrated on a proper subgroup of Then, with probability 1,
converges towards l as n goes to infinity. The result also holds for any countable abelian group instead of . Other modes of convergence are considered (Cesaro convergence of order >1/2). The Cesaro convergence of expressions such that (X
n) (X
n+1) is also investigated. 相似文献
6.
S. P. Lalley 《Probability Theory and Related Fields》1986,72(2):195-213
Summary A renewal theorem is obtained for stationary sequences of the form n=(...,X
n-1,X
n,X
n+1...), whereX
n,
, are i.i.d. r.v.s. valued in a Polish space. This class of processes is sufficiently broad to encompass functionals of recurrent Markov chains, functionals of stationary Gaussian processes, and functionals of one-dimensional Gibbs states. The theorem is proved by a new coupling construction.Research supported by the National Science Foundation 相似文献
7.
Michael Leonard Levitan 《Probability Theory and Related Fields》1970,15(1):29-50
Summary Consider a discrete time parameter Markov Process with stationary probability functions, a general state spaceX and the Harris recurrence condition. This then implies the existence and essential uniqueness of a sigma-finite stationary measure. It is also assumed that the class of measurable sets contains single point sets. LetP
(m)(x, S) denote them-step transition probability fromx toS andp
(m)(x, ·), the component ofP
(m)(x, ·) which is absolutely continuous with respect to. Let =C: C, for some
and
}. The paper here presented contains theorems of which the following is typical:Theorem: LetS with(S)>0, measurableBS, (B)>0 andqB with
uniformly iny, yB for all non-negative measurable f. Then for all measurableAS with(A)>0,k=0,±1, ±2,...
in measure onS. If the g.c.d. ()=1 and with(X)< then the above limit holds in measure onX.This research was partially supported by National Science Foundation Grant Gp-3906.The author would like to convey his appreciation to Professor Steven Orey for his invaluable guidance, advice and encouragement. 相似文献
8.
Johannes Schoissengeier 《Monatshefte für Mathematik》1992,114(2):139-147
A proof of the formula
for locally compact fields
andC
1-isomorphisms :UV, whereU andV are open subsets of
, was never published. In this paper we give two short proofs, one of them is a more elementary variant of the other. 相似文献
9.
Marian Nowak 《Czechoslovak Mathematical Journal》2000,50(2):401-414
Let
be a real Banach space and let E be an ideal of L
0 over a -finite measure space (, , ). Let (X) be the space of all strongly -measurable functions f: X such that the scalar function
, defined by
, belongs to E. The paper deals with strong topologies on E(X). In particular, the strong topology
the order continuous dual of E(X)) is examined. We generalize earlier results of [PC] and [FPS] concerning the strong topologies. 相似文献
10.
O. Naselli 《Journal of Optimization Theory and Applications》1996,91(1):81-90
In this paper, we present a class of functions:f:X such that inf
xX
f(x)=
, whereX is a nonempty, finitely compact and convex set in a vector space andB
x
={xX: y aff(X){x:[x, y]X={x}. Our main tool is a recent minimax theorem by Ricceri (Ref. 1). 相似文献
11.
Prof. Ottmar Loos 《Monatshefte für Mathematik》1978,86(2):107-129
Every Jordan pair
defines an algebraic varietyX containing
as a dense open subset.X is projective (affine) if and only if
is separable (radical). The Picard group ofX is generated by the irreducible factors of the generic norm of
. If
is separable then the automorphism group ofX is the projective group of
. 相似文献
12.
Z. Shi 《Journal of Theoretical Probability》1997,10(3):625-642
Let X
t and Y
t be respectively the locations of the maximum and minimum, over [0, t], of a real-valued Wiener process. We establish limsup and liminf iterated logarithm laws for
, the time difference between the maximum and the minimum, as well as for max(X
t, Y
t) and min(X
t, Y
t). 相似文献
13.
Ryoji Fukuda 《Probability Theory and Related Fields》1990,85(4):505-521
Summary In this paper we define two classes of Banach space (B, ·)-valued random vectors called sub-Gaussian vectors and -sub-Gaussian vectors. The main purpose of this paper is to prove the exponential integrability of a sub-Gaussian vectorX, that is,
for some >0, in the case whereB=L
p
. On the other hand, using the arguments ofX. Fernique and M. Talagrand, we also show that the exponential integrability of a -sub-Gaussian vector in an arbitrary separable Banach space.These two definitions of sub-Gaussian vectors and -sub-Gaussian vectors are not comparable, and neither of these definitions is a necessary condition for the exponential integrability. We shall give illuminating examples. 相似文献
14.
Mervyn J. Silvapulle Pranab K. Sen 《Annals of the Institute of Statistical Mathematics》1993,45(1):159-171
Consider the linear modelY=X+E in the usual matrix notation where the errors are independent and identically distributed. We develop robust tests for a large class of one- and two-sided hypotheses about when the data are obtained and tests are carried out according to a group sequential design. To illustrate the nature of the main results, let
and
be anM- and the least squares estimator of respectively which are asymptotically normal about with covariance matrices 2(X
t
X)–1 and 2(X
t
X)–1 respectively. Let the Wald-type statistics based on
and
be denoted byRW andW respectively. It is shown thatRW andW have the same asymptotic null distributions; here the limit is taken with the number of groups fixed but the numbers of observations in the groups increase proportionately. Our main result is that the asymptotic Pitman efficiency ofRW relative toW is (2/2). Thus, the asymptotic efficiency-robustness properties of
relative to
translate to asymptotic power-robustness ofRW relative toW. Clearly, this is an attractive result since we already have a large literature which shows that
is efficiency-robust compared to
. The results of a simulation study show that with realistic sample sizes,RW is likely to have almost as much power asW for normal errors, and substantially more power if the errors have long tails. The simulation results also illustrate the advantages of group sequential designs compared to a fixed sample design, in terms of sample size requirements to achieve a specified power. 相似文献
15.
We prove four theorems about groups with a dihedral (or cyclic) image containing a difference set. For the first two, suppose G, a group of order 2p
with p an odd prime, contains a nontrivial (v, k, ) difference set D with order n = k – prime to p and self-conjugate modulo p. If G has an image of order p, then 0 2a +
2
for a unique choice of = ±1, and for a = (k –
)/2p. If G has an image of order 2p, then
and
(
– 1)/(
– 1). There are further constraints on n, a and . We give examples in which these theorems imply no difference set can exist in a group of a specified order, including filling in some entries in Smith's extension to nonabelian groups of Lander's tables. A similar theorem covers the case when p|n. Finally, we show that if G contains a nontrivial (v, k, ) difference set D and has a dihedral image D
2m
with either (n, m) = 1 or m = p
t
for p an odd prime dividing n, then one of the C
2 intersection numbers of D is divisible by m. Again, this gives some non-existence results. 相似文献
16.
Qiguang Wu 《应用数学学报(英文版)》1993,9(3):281-288
LetY be distributed according to ann-variate normal distribution with a meanX and a nonsingular covariance matrix
2
V, where bothX andV are known, R
p
is a parameter, > 0 is known or unknown. Denote
and
. Assume thatF is linearly estimable. When is known, it is proved that the unbiased loss estimator
2tr(F(XV
–1
X)–
F) of
is admissible for rank (F)=k4 and inadmissible fork 5 with the squared error loss
. When is unknown and rank (X) <n, it is established that the loss estimatorcS
2, wherec is any nonnegative constant, of
is inadmissible and that the unbiased loss estimator tr(F(XV
–1
X)–
F) of
is admissible fork 4, and inadmissible fork 5 with squared error loss.This project is supported by the National Natural Science Foundation of China. 相似文献
17.
Á. Császár 《Acta Mathematica Hungarica》2001,91(3):187-193
Let X be a set, X
i X for i I and, for x X,
a filter in X
i. The paper gives necessary and sufficient conditions for the existence of a topology on X compatible with
, i.e. such that
is the trace on X
i of the -neighbourhood filter of x. It is shown that, among these compatible topologies,there are always a coarsest one and a finest one. Some applications are also given. 相似文献
18.
Andrzej Nowik 《Czechoslovak Mathematical Journal》2000,50(4):865-877
We prove the following theorems:1. There exists an -covering with the property s
0.2. Under cov
there exists X such that
is not an -covering orX \ B is not an -covering].3. Also we characterize the property of being an -covering. 相似文献
19.
Joseph Rosenblatt 《Mathematische Annalen》1977,230(3):245-272
For a mean zero norm one sequence (f
n
)L
2[0, 1], the sequence (f
n
{nx+y}) is an orthonormal sequence inL
2([0, 1]2); so if
, then
converges for a.e. (x, y)[0, 1]2 and has a maximal function inL
2([0, 1]2). But for a mean zerofL
2[0, 1], it is harder to give necessary and sufficient conditions for theL
2-norm convergence or a.e. convergence of
. Ifc
n
0 and
, then this series will not converge inL
2-norm on a denseG
subset of the mean zero functions inL
2[0, 1]. Also, there are mean zerofL[0, 1] such that
never converges and there is a mean zero continuous functionf with
a.e. However, iff is mean zero and of bounded variation or in some Lip() with 1/2<1, and if |c
n
| = 0(n
–) for >1/2, then
converges a.e. and unconditionally inL
2[0, 1]. In addition, for any mean zerof of bounded variation, the series
has its maximal function in allL
p[0, 1] with 1p<. Finally, if (f
n
)L
[0, 1] is a uniformly bounded mean zero sequence, then
is a necessary and sufficient condition for
to converge for a.e.y and a.e. (x
n
)[0, 1]. Moreover, iffL
[0, 1] is mean zero and
, then for a.e. (x
n
)[0, 1],
converges for a.e.y and in allL
p
[0, 1] with 1p<. Some of these theorems can be generalized simply to other compact groups besides [0, 1] under addition modulo one. 相似文献
20.
ONBAHADURASYMPTOTICEFFICIENCYINASEMIPARAMETRICREGRESSIONMODELLIANGHUA(梁华);CHENGPING(成平)(InstituteofSystemsScience,theChineseA... 相似文献