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1.
§ 1.Introduction  All maps considered in this paperare continuous.According to the papers of Xiong J.C.and Ye X.D.etal.,the depth of the center of f is atmost2 when f is a map on theunit interval(see[1 ] ) ;at most3 when f is a map on a tree(see[2 ] ) ;at most4 whenf is a map on the Warsaw circle(see[3 ] ) .In this note,an upper bound ofthe depth ofthe center of a map on a class of continua is obtained.  By a continuum we mean a compact connected metric space.A subcontinuum is asubset o…  相似文献   

2.
The purpose of this paper is to investigate the mean size formula of wavelet packets (wavelet subdivision tree) on Heisenberg group. The formula is given in terms of the p-norm joint spectral radius. The vector refinement equations on Heisenberg group and the subdivision tree on the Heisenberg group are discussed. The mean size formula of wavelet packets can be used to describe the asymptotic behavior of norm of the subdivision tree.  相似文献   

3.
李娜 《数学季刊》1993,8(1):81-87
The paper[1] constructs the conglomerate axiom system ACG in order to research the base of Category Theory.This paper constructs the model Ω^(B)(where B is a complete Boolean algebra) on the basis of the models △^(B) (see[2])and ∧^(B)(see[5]),and proves:(1)Ω^(B) is Boolean-Valued model of the conglomerate axiom system ACG;(2)The maximum and minimum principles are true in Ω^(B).  相似文献   

4.
Given any infinite tree in the plane satisfying certain topological conditions, we construct an entire function f with only two critical values ±1 and no asymptotic values such that f~(-1)([-1, 1]) is ambiently homeomorphic to the given tree. This can be viewed as a generalization of the result of Grothendieck(see Schneps(1994)) to the case of infinite trees. Moreover, a similar idea leads to a new proof of the result of Nevanlinna(1932) and Elfving(1934).  相似文献   

5.
Let B(H) be the algebra of bounded linear operators acting on a separable Hilbert space H. An operator T in B(H) is said to be strongly irreducible (see [1]), denoted by T (SI), if it is not similar to any reducible operator (see [2]). If the dimension of ?i is finite, B(H) may be regarded as an n × n matrix algebra. In this case, T (SI) if and only if T is similar to a Jordanian block. Jordanian canonical form theorem is one of the most important theorems in matrix theory. The Jordan…  相似文献   

6.
Inequalities of Korn's type on a surface with boundary have been proved in many papers using different techniques (see e.g. [4, 5, 11]). The author proves here an inequality of Korn's type on a compact surface without boundary. The idea is to use a finite number of maps for defining the surface and the inequality of Korn's type without boundary conditions for every map and to recast these in a general functional analysis setting about quotient spaces.  相似文献   

7.
In this paper,we investigate the existence and uniqueness of positive solutions to a class of singular fractional boundary value problem.The existence of positive solutions to the problem is based on a fixed point theorem in partially ordered sets.  相似文献   

8.
The motivation mainly comes from the conditions of congruences to be regular that are of importance and interest in ordered semigroups. In 1981, Sen has introduced the concept of the Γ-semigroups. We can see that any semigroup can be considered as a Γ-semigroup. In this paper, we introduce and characterize the concept of the regular congruences on ordered Γ-semigroups and prove the following statements on an ordered Γ-semigroup M : (1) Every ordered semilattice congruences is a regular congruence. (2) There exists the least regular order on the Γ-semigroup M/ρ with respect to a regular congru- ence ρ on M . (3) The regular congruences are not ordered semilattice congruences in general.  相似文献   

9.
1 IntroductionAs we know, any given quadratic system which may have limit cycle (LC,fOr abbreviation) can be written in the fOllowing fOrm (see [1] 512)where 6, l, m, n, a, 6 are all real parameters.If all trajectories of a quadratic system remain bounded fOr t 2 0, we saythat the system is bounded, and fOr abbreviation denote by BQS in this paper.The research work for BQS begin with Dickson-Perko [3]. And then, in [4],they made use of the conclusions of [51 to give a detailed classifica…  相似文献   

10.
The core problem of dynamical systems is to study the asymptotic behaviors of orbits and their topological structures. It is well known that the orbits with certain recurrence and generating ergodic (or invariant) measures are important, such orbits form a full measure set for all invariant measures of the system, its closure is called the measure center of the system. To investigate this set, Zhou introduced the notions of weakly almost periodic point and quasi-weakly almost periodic point in 1990s, and presented some open problems on complexity of discrete dynamical systems in 2004. One of the open problems is as follows: for a quasi-weakly almost periodic point but not weakly almost periodic, is there an invariant measure generated by its orbit such that the support of this measure is equal to its minimal center of attraction (a closed invariant set which attracts its orbit statistically for every point and has no proper subset with this property)? Up to now, the problem remains open. In this paper, we construct two points in the one-sided shift system of two symbols, each of them generates a sub-shift system. One gives a positive answer to the question above, the other answers in the negative. Thus we solve the open problem completely. More important, the two examples show that a proper quasi-weakly almost periodic orbit behaves very differently with weakly almost periodic orbit.  相似文献   

11.
§ 1 IntroductionIt is well known that quasi-likelihood models introduced by Wedderburn[1 ] greatlywiden the scope of generalized linear models by using a much weaker assumption in whichonly the firstand second moments ofresponse vector Yare needed to replace the full distri-butional assumption about Y in the models.It has drawn considerable attention in recentliterature(e.g.see[2~ 6] and so on) .However,little work has been done on the issuefrom a geometric viewpoint.The purpose of this p…  相似文献   

12.
The first problem considered in this article reads: is it possible to find upper estimates for the spanning tree congestion in bipartite graphs, which are better than those for general graphs? It is proved that there exists a bipartite version of the known graph with spanning tree congestion of order n 3 2 , where n is the number of vertices. The second problem is to estimate spanning tree congestion of random graphs. It is proved that the standard model of random graphs cannot be used to find graphs whose spanning tree congestion has order greater than n 3 2 .  相似文献   

13.
The alternating direction method of multipliers(ADMM)is a benchmark for solving convex programming problems with separable objective functions and linear constraints.In the literature it has been illustrated as an application of the proximal point algorithm(PPA)to the dual problem of the model under consideration.This paper shows that ADMM can also be regarded as an application of PPA to the primal model with a customized choice of the proximal parameter.This primal illustration of ADMM is thus complemental to its dual illustration in the literature.This PPA revisit on ADMM from the primal perspective also enables us to recover the generalized ADMM proposed by Eckstein and Bertsekas easily.A worst-case O(1/t)convergence rate in ergodic sense is established for a slight extension of Eckstein and Bertsekas’s generalized ADMM.  相似文献   

14.
It is the main aim in this papar to establish isomorphic relation between an equibottom tree class and an integeral sequence,and to study emphatically the expanding process of a tree and the iterative algorithm on the tree data.  相似文献   

15.
Kenneth R. Davidson raised ten open problems in the book Nest Algebras. One of theseopen problems isProblem 7 If K(交集)AlgL is weak^* dense in AlgL, where K is the set of all compact operators in B(H),is L completely distributive? In this note, we prove that there is a reflexive subspace lattice L on some Hilbert space, which satisfies the following conditions: (a)F(AlgL) is dense in AlgL in the ultrastrong operator topology, where F(AlgL) is the set of all finite rank operators in AlgL; (b) L isn‘t a completely distributive lattice. The subspace lattices that satisfy the above conditions form a large class of lattices. As a special case of the result, it easy to see that the answer to Problem 7 is negative.  相似文献   

16.
陶祥兴 《数学进展》2006,35(2):251-253
0 Introduction Because of applications to control theory, see Schmit and Week's work in [1], the following unique continuation question (UCP) was raised in [2-3]: if u is a harmonic function in a connected Lipschitz domainΩ, vanishing continuously on an open subsetΓof the boundary (?)Ωand whose normal derivative vanishes on a subset of Γof positive surface measure, does it follows that u is identically zero inΩ? On the other hand, the unique continuation problem has been focusing on second order equations in which the coefficients of the lower-order terms are allowed to be  相似文献   

17.
A piecewise-smooth second-order singularly perturbed differential equation whose right-hand side is a nonlinear function with a discontinuity on some curve is investigated. This is a new class of problems in the case where the degenerate equation has a multiple root on the left-hand side of the curve which separates the domain and an isolated root on the right-hand side of that curve. The asymptotics of a solution with an internal layer near a point on the discontinuous curve and the transition point is constructed. The method to construct the internal layer function is proposed. The behavior of the solution in the internal layer consisting of four zones essentially differs from the case of isolated roots. For sufficiently small parameter values, the existence of a smooth solution with an internal layer from the multiple root of the degenerate equation to the isolated root in the neighborhood of a point on the discontinuous curve is proved. The method can be shown to be effective in the given example.  相似文献   

18.
In this article, the author is devoted to establish the multiplicity of positive periodic solutions to second-order singular differential systems. It isproved that such a problem has at least two positive solutions under our reasonable conditions. The proof relies on a nonlinear alternative of Leray--Schauder type and Krasnoselskii fixed point theorem in cones.  相似文献   

19.
This paper is concerned with inverse acoustic source problems in an unbounded domain with dynamical boundary surface data of Dirichlet kind.The measurement data are taken at a surface far away from the source support.We prove uniqueness in recovering source terms of the form f(x)g(t)and f(x1,x2,t)h(x3),where g(t)and h(x3)are given and x=(x1,x2,x3)is the spatial variable in three dimensions.Without these a priori information,we prove that the boundary data of a family of solutions can be used to recover general source terms depending on both time and spatial variables.For moving point sources radiating periodic signals,the data recorded at four receivers are prove sufficient to uniquely recover the orbit function.Simultaneous determination of embedded obstacles and source terms was verified in an inhomogeneous background medium using the observation data of infinite time period.Our approach depends heavily on the Laplace transform.  相似文献   

20.
The authors consider the limiting behavior of various branches in a uniform recursive tree with size growing to infinity.The limiting distribution ofζ_(n,m),the number of branches with size m in a uniform recursive tree of order n,converges weakly to a Poisson distribution with parameter 1/m with convergence of all moments.The size of any large branch tends to infinity almost surely.  相似文献   

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