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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.
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   

6.
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   

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.
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   

9.
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   

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.
树映射的ω-极限集与湍流   总被引:2,自引:0,他引:2  
孙太祥 《数学学报》2002,45(2):253-260
设T是个树,f:T→T是个连续自映射, n是T的端点数,x∈T.本文证明:(1)如果存在z∈ω(x,f)∩F(f),使z是ω(x,f)的一个单侧聚点,那么一定存在r∈Nn-1,使fr含有湍流;(2)如果ω(x,f)是个含有不动点的无穷集,那么必存在r∈Nn,使fr含有湍流.  相似文献   

12.

Let M be a n -dimensional manifold with the same homology than the n -dimensional sphere. A C 1 map f : M M M is called transversal if for all m ] N the graph of f m intersects transversally the diagonal of M 2 M at each point ( x , x ) such that x is a fixed point of f m . We study the minimal set of periods of f by using the Lefschetz numbers for periodic points. In the particular case that n is even, we also study the set of periods for the transversal holomorphic self-maps of M .  相似文献   

13.
关于图中子图的(n,k)—正交因子分解   总被引:1,自引:0,他引:1  
李建湘 《数学研究》2001,34(4):339-344
设G是一个具有顶点集V(G)和边集E(G)的图. 设g和f是定义在V(G)上的两个整数值函数,使得g(x)f(x)对所有的点x∈V(G)都成立.如果G是一个(mg+n,mf-n)-图,1n<m2k,且g(x)2k-1对所有的点x∈V(G)都成立,则对任意给定具有|E(H)|=nk边的G的子图H,存在G的一个子图G′使G′有一个(g,f)-因子分解(n,k)-正交H.  相似文献   

14.
设G是一个图. 设g和f是两个定义在V(G)上的整值函数使得对V(G)所有的顶点x有g(x)f(x). 图G被称为(g,f,n)-临界图,如果删去G的任意n个顶点后的子图都含有G的(g,f)-因子. 本文给出了图是(a,b,n)-临界图几个充分条件. 进一步指出这些条件是最佳的. 例如,如果对V(G)所有的顶点x和y都有g(x)<f(x), n+g(x)dG(x)和g(x)/(dG(x)-n)f(y)/dG(y),则G是(g,f,n)-临界图.  相似文献   

15.
设X是一个紧致度量空间,f X→X是一个连续映射.若存在f的一个m-周期点p和另一个m'-周期点q(p≠q),使得对任意非空开集V(C)X,都有{p,q}(C)∞ Un=0fn(V),则称动力系统(X,f)是一个(m,m')型周期吸附系统.证明了:1)若(X,f)是一个(m,m')型周期吸附系统且X是自密的,则对任一给定的正整数k,存在一个fk的的分布混沌集S,使得S与X的任一非空开集之交均含有一个Cantor集;2)若(X,f)是一个(m,m')型周期吸附系统且拓扑共轭于(X ',f'),则(X ',f')也是一个(m,m')型周期吸附系统.改进和推广了已有结果.  相似文献   

16.
一类连续体上连续映射的周期点   总被引:1,自引:0,他引:1  
孙太祥  顾荣宝 《数学学报》2004,47(2):343-348
设X是个阶有限的遗传可分解可链连续体, f:X→X是X上的连续自映射, On(x,f)={fi(x):0≤i≤n)是f的一个返回轨道, inf(On(x,f))相似文献   

17.
设n,m和r是满足r≥2,n≥0,m≥3的整数,且当r是奇数时,假设r≥m-1.称一个图为K1,m-free,如果它不包含以Kt,m为导出的子图.称一个图G为一个(r,n)-临界图,如果在删去G的任意n个点后,剩下G的子图都有一个r-因子,设G是一个Kl,m-free的(n+1)-连通图,且阶为|G|以及r(|G|≥n)是偶数,证明了:如果G的最小度至少是r+n+m-1,阶|G|≥8r5+n,并且对V(G)的任意独立点集{x1,x2}都有|NG(x1)∪NG(x2)|≥(|G|+n)/2,那么G是一个(r,n)-临界图.关于G的最小度和|NG(x1)∪NG(X2)|的下界是紧的。  相似文献   

18.
19.
设β1为实数,T_β为[0,1]的β变换.攀援集的任何两个点随着时间的转移会越来越接近但同时又总能在任意长时间后保持一定的距离.证明了在Lebesgue测度意义下关于T_β的攀援集是一个零测集.Distal点对的两个点表示随着时间的转移始终保持着一定的距离.如果固定其中一个点x_0,所有满足x∈[0,1)且lim inf n→∞|T_β~n(x)-T_β~n(x_0)|0的点称为关于x_0的distal集,如果把这个集合记为R_β(x_0),根据Borel-Cantelli引理得到R_β(x_0)的Lebesgue测度为零.  相似文献   

20.
An Algol 60 procedure is described which will estimate the first, second or third order derivative of a function f(x) at a point x0, using polynomial interpolation to values of f(x) at points on the real axis. This procedure does not require the user to provide information about the accuracy of the function values. The procedure itself monitors the noise level in these values, and allows for the effect of noise on the estimated derivative. The evaluation points may be restricted to one side of x0 if f(x) makes this necessary, and are chosen either to minimise the error in the result, or to achieve a specified tolerance with as few function evaluations as possible.  相似文献   

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