共查询到20条相似文献,搜索用时 343 毫秒
1.
Gerold Alsmeyer 《Journal of Theoretical Probability》2002,15(2):259-283
It is proved that for each random walk (S
n
)
n0 on
d
there exists a smallest measurable subgroup
of
d
, called minimal subgroup of (S
n
)
n0, such that P(S
n
)=1 for all n1.
can be defined as the set of all x
d
for which the difference of the time averages n
–1
n
k=1
P(S
k
) and n
–1
n
k=1
P(S
k
+x) converges to 0 in total variation norm as n. The related subgroup
* consisting of all x
d
for which lim
n P(S
n
)–P(S
n
+x)=0 is also considered and shown to be the minimal subgroup of the symmetrization of (S
n
)
n0. In the final section we consider quasi-invariance and admissible shifts of probability measures on
d
. The main result shows that, up to regular linear transformations, the only subgroups of
d
admitting a quasi-invariant measure are those of the form
1×...×
k
×
l–k
×{0}
d–l
, 0kld, with
1,...,
k
being countable subgroups of
. The proof is based on a result recently proved by Kharazishvili(3) which states no uncountable proper subgroup of
admits a quasi-invariant measure. 相似文献
2.
Izu Vaisman 《Annals of Global Analysis and Geometry》2001,19(3):209-234
The transversal twistor space of a foliation
of an even codimension is the bundle
of the complex structures of the fibers of the transversalbundle of
. On
there exists a foliation
by covering spaces of the leaves of
, and any Bottconnection of
produces an ordered pair
of transversal almost complex structures of
. The existence of a Bott connection which yields a structure
1 that is projectable to the space of leaves isequivalent to the fact that
is a transversallyprojective foliation. A Bott connection which yields a projectablestructure
2 exists iff
isa transversally projective foliation which satisfies a supplementarycohomological condition, and, in this case,
1is projectable as well.
2 is never integrable.The essential integrability condition of
1 isthe flatness of the transversal projective structure of
. 相似文献
3.
We find a regular deformation retraction
n,r
(K): Idem
n,r
(K) G
n,r
(K) from the manifold Idem
n,r
(K) of idempotent n × n matrices with rank r to the Grassmannian manifold G
n,r
(K) over K the reals, complex numbers or quaternions. Then we derive an injection
from the sets of homotopy classes of complex-valued polynomial to such a set of real-valued regular maps, where
denotes the Zariski closure in the affine space
n
of a subset
n
. Furthermore, we list complex-valued polynomial maps
2
2 of any Brouwer degree and deduce that the map ()2,1: Idem()2,1 G()2,1 yields an isomorphism
[
2
]
[
2,
2] of cyclic infinite homotopy groups. Finally, we show that every nonzero even Brouwer degree of the spheres
n
and
n
cannot be realized by a real-valued (resp. complex-valued) homogeneous polynomial map provided that n is even. 相似文献
4.
We study the contact process in
d
and a family of two-parametric oriented percolation models in
d
×
+. It is proved that the derivative at the endpoint of the critical curve for percolation exists and its absolute value coincides with the critical rate for the corresponding contact process. 相似文献
5.
Frédéric Paulin 《Geometriae Dedicata》2002,95(1):65-85
The aim of this paper is to give a geometric interpretation of the continued fraction expansion in the field
of formal Laurent series in X
–1 over
, in terms of the action of the modular group
on the Bruhat–Tits tree of
, and to deduce from it some corollaries for the diophantine approximation of formal Laurent series in X
–1 by rational fractions in X. 相似文献
6.
N. A. Shirokov 《Journal of Mathematical Sciences》2005,129(4):4083-4086
Let
n be the unit ball in ℂn, n ≥ 2. Let Tα = {z ∈
n : (z, a) = |a|2} for a ∈
n and denote
for a discrete set A in
n. We find a sharp necessary condition for a set A to be a part of the zero-set for a function in H∞(
n). Bibliography 4 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 303, 2003, pp. 272–278. 相似文献
7.
Florence Merlevède Magda Peligrad Sergey Utev 《Journal of Theoretical Probability》1997,10(3):681-693
In this paper we study the behavior of sums of a linear process
associated to a strictly stationary sequence
with values in a real separable Hilbert space and
are linear operators from H to H. One of the results is that
satisfies the CLT provided
are i.i.d. centered having finite second moments and
. We shall provide an example which shows that the condition on the operators is essentially sharp. Extensions of this result are given for sequences of weak dependent random variables
under minimal conditions. 相似文献
8.
ALAIN HÉNAUT 《Geometriae Dedicata》1997,65(1):89-101
A d-web in (
,0) is given by d complex analytic foliations of codimension one in (
,0) which are in general position. A d-web
in (
,0) is linear if all the leaves are (pieces of) hyperplanes in
and
is algebraic if it is associated, by duality, to a nondegenerate algebraic curve in
of degree d. We characterize linear webs in (
,0). We give explicit conditions under which a linear d-web in (
,0) is algebraic and we obtain equations for
in this case. Some related problems are discussed and some questions are posed. 相似文献
9.
Wiesław Śliwa 《Czechoslovak Mathematical Journal》2004,54(2):457-463
We prove that any infinite-dimensional non-archimedean Fréchet space E is homeomorphic to
where D is a discrete space with card(D) = dens(E). It follows that infinite-dimensional non-archimedean Fréchet spaces E and F are homeomorphic if and only if dens(E) = dens(F). In particular, any infinite-dimensional non-archimedean Fréchet space of countable type over a field
is homeomorphic to the non-archimedean Fréchet space
. 相似文献
10.
Let
be an entire function of finite type with respect to finite order
and let
be a subset of an open cone in a certain n-dimensional subspace
(the smaller
, the sparser
). We assume that this cone contains a ray
0} \right\}$$
" align="middle" border="0">
. It is shown that the radial indicator
of
at any point
may be evaluated in terms of function values at points of the discrete subset
. Moreover, if
tends to zero fast enough as
over
, then this function vanishes identically. To prove these results, a special approximation technique is developed. In the last part of the paper, it is proved that, under certain conditions on
and
, which are close to exact conditions, the function
bounded on
is bounded on the ray. 相似文献
11.
Joseph H. Silverman 《Designs, Codes and Cryptography》2000,20(1):5-40
Let
be an elliptic curve defined over a finite field, and let
be two points on E. The Elliptic Curve Discrete Logarithm Problem (ECDLP) asks that an integer m be found so that S=mT in
. In this note we give a new algorithm, termed the Xedni Calculus, which might be used to solve the ECDLP. As remarked by Neal Koblitz, the Xedni method is also applicable to the classical discrete logarithm problem for
and to the integer factorization problem. 相似文献
12.
Sjoerd E. Crans 《K-Theory》2003,28(1):39-105
Let
be n-dimensional teisi, i.e., higher-dimensional Gray-categorical structures. The following questions can be asked. Does a left q-transfor
, i.e., a functor 2
q
, induce a right q-transfor
, i.e., a functor
More generally, does a functor
induce a functor
For k-arrows c and
whose (k – 1)-sources and targets agree, does a q-transfor
induce a q-transfor
, for appropriate k-arrows
For k-arrows c and
whose (k – 1)-sources and targets agree, does a q-transfor
induce a (q + k + 1)-transfor
, for appropriate k-arrows
I give answers to these questions in the cases where n-dimensional teisi and their tensor product have been defined, i.e., for n 3, and for n up to 5 in some cases that do not need all data and axioms of n-dimensional teisi.I apply the above to compositions in teisi, in particular to braidings and syllepses. One of the results is that a braiding on a monoidal 2-category induces a pseudo-natural transformation
, where
is the reverse of ? –, which is almost, but not quite, equal to – ?. However, in higher dimensions need not be reversible, so a braiding on a higher-dimensional tas can not be seen as a transfor A B B A. 相似文献
13.
Using an analog of the classical Frobenius recursion, we define the notion of a Frobenius
-homomorphism. For
, this is an ordinary ring homomorphism. We give a constructive proof of the following theorem. Let X be a compact Hausdorff space,
the
th symmetric power of X, and
the algebra of continuous complex-valued functions on X with the sup-norm; then the evaluation map
defined by the formula
identifies the space
with the space of all Frobenius
-homomorphisms of the algebra
into
with the weak topology. 相似文献
14.
Niels Jakob Laustsen 《K-Theory》2001,22(3):241-249
Let
Figiel's reflexive Banach space which is not isomorphic to its Cartesian square. We show that the K
0group of the algebra
of continuous, linear operators on
contain a subgroup isomorphic to the group c
00(
) of sequences
rational numbers with z
n=0 eventually. 相似文献
15.
We prove the absolute continuity of the spectrum of the Schrödinger operator in
,
, with periodic (with a common period lattice
) scalar
and vector
potentials for which either
,
, or the Fourier series of the vector potential
converges absolutely,
, where
is an elementary cell of the lattice
,
for
, and
for
, and the value of
is sufficiently small, where
and
otherwise,
, and
. 相似文献
16.
E. Getzler 《Compositio Mathematica》2002,132(2):121-135
We calculate the Euler characteristics of the local systems S
k
S
2
on the moduli space
2 of curves of genus 2, where
is the rank 4 local system R
1 *
. 相似文献
17.
We show that if two Riemannian metrics
and g are pointwiseprojectively equivalent and the Ricci curvatures satisfy
Ric, then the projective equivalence is trivialprovided that g is complete. In this case,
is parallel with respect to g and the Riemann curvatures of g and
are equal.The Ricci curvature condition can be weakened when the manifold iscompact. This rigidity theorem actually holds for more general geometricstructures, such as Finsler metrics and sprays. In this paper, we willalso discuss several examples and show that the completeness of g cannot be dropped. 相似文献
18.
Special Lagrangian Submanifolds with Isolated Conical Singularities. II. Moduli spaces 总被引:1,自引:1,他引:0
This is the second in a series of five papers studying special Lagrangiansubmanifolds (SLV m-folds) X in (almost) Calabi–Yau m-folds
M with singularities x
1
, ..., x
n
locally modelled on specialLagrangian cones
C
1, ..., C
n
in
m
with isolated singularities at 0.Readers are advised to begin with Paper V.This paper studies the deformation theory of compact SL m-folds X in Mwith conical singularities. We define the moduli space
X
of deformations of X in M, and construct a natural topology on it. Then we show that
X
is locally homeomorphic to the zeroes of a smooth map :
X
X between finite-dimensional vector spaces.Here the infinitesimal deformation space
X depends only on the topology of X, and the obstruction space
X only on the cones C
1, ..., C
n
at x
1, ..., x
n
. If the cones C
i
are stable then
X is zero, and
X
is a smooth manifold. We also extend our results to families of almost Calabi–Yau structures on M. 相似文献
19.
B. N. Cooperstein 《Designs, Codes and Cryptography》2001,23(2):185-196
The projective plane
is embedded as a variety of projective points
in
, where M is a nine dimensional
-module for the groupG=GL(3,q
2). The hyperplane sections of thisvariety and their stabilizers in the group G aredetermined. When q 2 (mod 3) one such hyperplanesection is a member of the family of Kantor's unitary ovoids.We furtherdetermine all sections
whereD has codimension two in M and demonstratethat these are never empty. Consequences are drawn for Kantor'sovoids. 相似文献
20.
Let
be a computable structure and let R be an additional relation on its domain. We establish a necessary and sufficient condition for the existence of an isomorphic copy
of
such that the image of R
is h-simple (h-immune) relative to
. 相似文献