共查询到20条相似文献,搜索用时 31 毫秒
1.
We theoretically investigate the asymptotical stability, local bifurcations and chaos of discrete-time recurrent neural networks
with the form of
, where the input-output function is defined as a generalized sigmoid function, such asv
i
=2/π arctan(π/2μiμi),
and
, etc. Numerical simulations are also provided to demonstrate the theoretical results. 相似文献
2.
Qikeng Lu 《中国科学A辑(英文版)》1998,41(12):1248-1254
In the complex Grassmann manifold ℱ(m,n), the space of complexn-planes passes through the origin of Cm+n; the local coordinate of the space can be arranged into anm ×n matrixZ. It is proved that
is a U(m)-connection of ℱ(m,n) and its curvature form
satisfies the Yang-Mills equation. Moreover,
is an (Sum)-connection and its curvature form
satisfies the Yang-Mills equation.
Project partially supported by the National Natural Science Foundation of China (Grant No. 19631010) and Fundamental Research
Bureau of CAS. 相似文献
3.
The asymptotic properties of the numbers of spanning trees and Eulerian trails in circulant digraphs and graphs are studied.
Let
be a directed circulant graph. Let
and
be the numbers of spanning trees and of Eulerian trails, respectively. Then
Furthermore, their line digraph and iterations are dealt with and similar results are obtained for undirected circulant graphs.
Project partially supported by the National Natural Science Foundation of China (Grant No. 69673042) and by Hong Kong CERG
(HKUST652/95E). 相似文献
4.
Aleksandar Ivić 《Central European Journal of Mathematics》2005,3(2):203-214
Let Δ(x) denote the error term in the Dirichlet divisor problem, and E(T) the error term in the asymptotic formula for the mean square of
. If E
*(t)=E(t)-2πΔ*(t/2π) with
, then we obtain
and
It is also shown how bounds for moments of | E
*(t)| lead to bounds for moments of
. 相似文献
5.
Consider the nonparametric regression model
, whereg is an unknown function to be estimated on [0, 1],
are the fixed design points in the interval [0, 1] and
is a triangular array of row iid random variables having median zero. The nearest neighbor median estimator
is taken as the estimator of the unknown functiong(x). Median cross validation (mev) criterion is employed to select the smoothing parameterh. Leth
π
*
be the smoothing parameter chosen by mev criterion. Under mild regularity conditions, the upper and lower bounds ofh
π
*
, the rate of convergence and the weak consistency of the median cross-validated estimate
are obtained.
Project supported by the National Natural Science Foundation of China and the Doctoral Foundation of Education of China. 相似文献
6.
Gensun Fang 《中国科学A辑(英文版)》1998,41(12):1272-1277
The Nikolskii type inequality for cardinal splines
is proved, which is exact in the sense of order, where ∈ ℒ
m,h
, and ℒ
m,k
is the space of cardinal splines with nodes
Project supported by the National Natural Science Foundation of China (Grant No. 19671012), and Doctoral Programme Foundation
of Institution of Higher Education. 相似文献
7.
R. Carroll 《Journal of Nonlinear Science》1994,4(1):519-544
Summary We use the SDiff(2) framework of Takasaki and Takebe and the (L, M) program (L is the Lax operator andMω=ωλ) to show that
=semiclassical limit ofM is
, where (
) are action angle variables in the Gibbons-Kodama theory of Hamilton-Jacobi type for dispersionless KP. We also show
is the semiclassical limit ofWxW
−1 (W is the gauge operator), whereG=WxW
−1 is a quantity studied by the author in an earlier paper in connection with symmetries. We give then a semiclassical version
of the Jevicki-Yoneya action principle for 2D gravity, where again
arises in calculations, and this yields directly the Landau-Ginsburg equation that corresponds to the semiclassical limit
of an integrated string equation. For KdV we also show how inverse scattering data are connected to Hamiltonians for dispersionless
KdV. We also discuss Hirota bilinear formulas relative to the dispersionless hierarchies and establish various limiting formulas. 相似文献
8.
A family of transitive modular Lie superalgebras with depth one 总被引:1,自引:0,他引:1
Wen-de LIU~ 《中国科学A辑(英文版)》2007,50(10):1451-1466
The embedding theorem is established for Z-graded transitive modular Lie superalgebras g=(?)satisfying the conditions: (i)g0(?)(g-1)and g0-module g-1 is isomorphic to the natural(?)(g-1)-module; (ii)dim g1=2/3n(2n~2 1),where n=1/2dim g-1. In particular,it is proved that the finite-dimensional simple modular Lie superalgebras satisfying the conditions above are isomorphic to the odd Hamiltonian superalgebras.The restricted Lie superalgebras are also considered. 相似文献
9.
The asymptotic expansions are studied for the vorticity
to 2D incompressible Euler equations with-initial vorticity
, where ϕ0(x) satisfies |d ϕ0(x)|≠0 on the support of
and
is sufficiently smooth and with compact support in ℝ2 (resp. ℝ2×T) The limit,v(t,x), of the corresponding velocity fields {v
ɛ(t,x)} is obtained, which is the unique solution of (E) with initial vorticity ω0(x). Moreover,
(ℤ2)) for all 1≽p∞, where
and ϕ(t,x) satisfy some modulation equation and eikonal equation, respectively. 相似文献
10.
L. V. Kritskov 《Mathematical Notes》1999,65(4):454-461
Suppose thatА is a nonnegative self-adjoint extension to {
} of the formal differential operator−Δu+q(x)u with potentialq(x) satisfying the condition {
} or the condition {
} in which the nonnegative function itχ(r) is such that {
}. For each α∈(0, 2], we establish an estimate of the generalized Fourier transforms of an arbitrary function {
} of the form {
} If, in addition, {
}, then, along with this estimate, a similar lower bound is established.
Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 542–551, April, 1999. 相似文献
11.
L. I. Danilov 《Mathematical Notes》1997,61(1):48-57
We consider Stepanov almost periodic functions μ ∈
ranging in the metric space
of Borel probability measures on a complete separable metric space
is equipped with the Prokhorov metric). The main result is as follows: a function
, belongs to
if and only if for each bounded continuous function
, the function
is Stepanov almost periodic (of order 1) and
Translated fromMatematicheskie Zametki, Vol. 61, No. 1, pp. 57–68, January, 1997.
Translated by I. P. Zvyagin 相似文献
12.
By means of a method of analytic number theory the following theorem is proved. Letp be a quasi-homogeneous linear partial differential operator with degreem,m > 0, w.r.t a dilation
given by ( a1, …, an). Assume that either a1, …, an are positive rational numbers or
for some
Then the dimension of the space of polynomial solutions of the equationp[u] = 0 on ℝn must be infinite 相似文献
13.
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
14.
O. P. Filatov 《Mathematical Notes》1999,66(3):348-354
For a continuous almost periodic function
, we show that the function
where the supremum is taken over all solutions of the system of differential inclusion
,
, has the following limit (as μ→+0):
, Thus if the parameter μ is small, then
and the limit of the maximal mean can approximately be determined by solving problems of smaller dimensionality. Moreover,
if the compact sets
and
are nondegenerate, then Ψ
f
is independent of initial data.
Translated fromMatematicheskie Zametki, Vol. 66, No. 3, pp. 431–438, September, 1999. 相似文献
15.
Yasunori Fujikoshi Yoshimichi Ochi 《Annals of the Institute of Statistical Mathematics》1984,36(1):119-128
Summary In this paper we obtain an asymptotic expansion of the distribution of the maximum likelihood estimate (MLE)
based onT observations from the first order Gaussian process up to the term of orderT
−1. The expansion is used to compare
with a generalized estimate
including the least square estimate (LSE)
, based on the asymptotic probabilities around the true value of the estimates up to the terms of orderT
−1. It is shown that
(or the modified MLE
) is better than
(or the modified estimate
). Further, we note that
does not attain the bound for third order asymptotic median unbiased estimates. 相似文献
16.
17.
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
18.
In this article, the operator
is introduced and named as the Bessel diamond operator iteratedk times and is defined by
where
,i = 1, 2, ...,n
k is a non-negative integer andn is the dimension of ℝ
n
+
. In this work we study the elementary solution of the Bessel diamond operator and the elementary solution of the operator
is called the Bessel diamond kernel of Riesz. Then, we study the Fourier-Bessel transform of the elementary solution and
also the Fourier-Bessel transform of their convolution. 相似文献
19.
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
20.
This paper deals with the problem of small oscillations in a liquid layer of finite depth under the assumption that the bottom
is an elastic medium. The system of equations corresponding to the problem is written out and explained. The main aim of the
paper is to recast these equations in the form
, where
and
are positive operators in the function space naturally corresponding to the problem. The further aim is to investigate the
spectrum of the linear pencil
, which determines the dynamics of the problem.
Translated fromMatematicheskie Zametki, Vol. 68, No. 1, pp. 66–81, July, 2000. 相似文献
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