关于任意随机可积序列的一个强收敛定理

本文研究了可积随机适应序列强收敛定理的问题.利用构造截尾停时以及鞅差序列的方法,获得了一类任意积随机适应序列的强收敛定理,推广了若干已知的结果.     

三角恒等变换及其应用

三角恒等变换是指利用同角公式、诱导公式、两角和与差的三角函数公式、和差化积与积化和差公式、万能公式等对三角式做各种有目的的变形．变形中主要涉及角、函数、名、结构、运算方式的变换，其技巧常有差异分析、化异为同、辅助角、三角代换、和差配凑、幂指变换等．     

等差数列的方幂和

近几年来,国内外还不断有人讨论自然数方幂和的求法(见[1]～[4]),本文研究等差数列的方幂和问题,得到一个简单的求和方法.并导出了一个自然数方幂和公式。首先,我们介绍“循环积和”的概念及其有关结果。设{a_n}为等差数列,记 a_ k~(r)=a_k a_(k 1)…a_(k r-1),k=1,2,3,…我们把数列{a_k~(r)}叫做等差数列{a_n}的r阶循环积,而将和 S_n~(r)=a_1(r) a_2(r) …a_n~(r)叫做数列{a_n}的r阶循环积和,简称循环积和。我们有[5] S_n~(r)=1/(r 1)d[a_n(r 1)-a_0~(r 1)] (1)其中d为{a_n}的公差,a_0=a_1=d。特别,令a_n=n,则对自     

幂超格的性质

对幂超格的性质进行了研究.给出了幂超格直积、分配幂超格的概念并讨论了他们的性质.     

满足a+ab=a+b的幂等半环的结构

本文讨论了满足a+ab=a+b的幂等半环的结构,给出这种幂等半环是左零半环的伪强右正规幂等半环,并得出这种幂等半环与环的直积是左环的伪强右正规幂等半环.     

关于有限群两个幂零子群积的问题

众所周知,有限群的两个幂零子群的积不一定是幂零的．本文研究了Ｅｎｇｅｌ条件对两个幂零子群的影响,得到两个幂零子群的积为幂零群的几个充分条件。     

满足a＋ab=a＋b幂等半环的结构

本讨论了满足a ab=a b的幂等半环的结构，给出了这种幂等半环是左零半环的伪强右正规幂等半环，并得出这种幂等半环与环的直积是左环的伪强右正规幂等半环。     

关于在∧-∨复合之下格矩阵的收敛性

本文研究了在复合∧-∨下格矩阵幂序列的收敛性，利用格中∧与∨运算的特性，获得了格矩阵幂序列的一些性质，证明了在∧-∨复合下．任一个几乎非自反格矩阵的幂序列是递减与收敛的．     

基于小波变换的小样本随机振荡序列灰色预测模型

针对GM(1,1)幂模型对于小样本振荡序列对含突变信息无能为力的问题,提出了基于小波变换的小样本振荡序列灰色预测模型.首先,针对原始数据序列建立GM(1,1)幂模型描述其总体趋势特征;然后,利用小波变换提取GM(1,1)幂模型残差序列所包含的有用信号和随机噪声,并结合GM(1,1)幂模型构成新的时间相应函数;最后,以与原始平均误差最小为原则确定小波变换的小波基和分解层次并对小波进行重构GM(1,1)幂模型残差序列,并结合原始GM(1,1)幂模型对随机振荡序列进行预测.算例中通过对城市用水量的拟合及预测结果表明:应用基于傅立叶变换的GM(1,1)幂振荡序列模型和基于分数阶离散GM(1,1)幂模型研究了振荡序列模型平均误差分别为3.22%和5.66%,而本文的方法平均误差为1.11%.算例研究表明,此方法能够快速高效的解决GM(1,1)幂模型对小样本有突变趋势振荡序列的预测问题.     

左消半群M与幂单半群N的Schüzenberger积

本文讨论了每个元都有幂等元作为右单位元的左消半群与幂单半群N的Schuzenberger积M◇N的ρ类,证明了这种半群M与N的Schuzenberger积M◇N的ρ类是右E-半适合半群和弱E-headged半群.     

On the cycle maximum of birth–death processes and networks of queues

This paper considers the cycle maximum in birth–death processes as a stepping stone to characterisation of the asymptotic behaviour of the maximum number of customers in single queues and open Kelly–Whittle networks of queues. For positive recurrent birth–death processes we show that the sequence of sample maxima is stochastically compact. For transient birth–death processes we show that the sequence of sample maxima conditioned on the maximum being finite is stochastically compact.We show that the Markov chain recording the total number of customers in a Kelly–Whittle network is a birth–death process with birth and death rates determined by the normalising constants in a suitably defined sequence of closed networks. Explicit or asymptotic expressions for these normalising constants allow asymptotic evaluation of the birth and death rates, which, in turn, allows characterisation of the cycle maximum in a single busy cycle, and convergence of the sequence of sample maxima for Kelly–Whittle networks of queues.     

On powers of the Catalan number sequence

The Catalan number sequence is one of the most famous number sequences in combinatorics and is well studied in the literature. In this paper we further investigate its fundamental properties related to the moment problem and prove for the first time that it is an infinitely divisible Stieltjes moment sequence in the sense of S.-G.  Tyan. Besides, any positive real power of the sequence is still a Stieltjes determinate sequence. Some more cases including (a) the central binomial coefficient sequence (related to the Catalan sequence), (b) a double factorial number sequence and (c) the generalized Catalan (or Fuss–Catalan) sequence are also investigated. Finally, we pose two conjectures including the determinacy equivalence between powers of nonnegative random variables and powers of their moment sequences, which is supported by some existing results.     

Triangle-free subgraphs of powers of cycles

We derive upper bounds for the number of edges in a triangle-free subgraph of a power of a cycle.     

On a Definitizable Analog of the Trigonometric Moment Problem Generating an Indefinite Toeplitz Form

We prove the existence of an integro-polynomial representation for a sequence of numbers such that there exists a difference operator mapping this sequence to a sequence that generates the solvable trigonometric moment problem. A similar result related to the power moment problem was given in [12].     

On a Definitizable Analog of the Trigonometric Moment Problem Generating an Indefinite Toeplitz Form

We prove the existence of an integro-polynomial representation for a sequence of numbers such that there exists a difference operator mapping this sequence to a sequence that generates the solvable trigonometric moment problem. A similar result related to the power moment problem was given in [12].     

Applying a combinatorial determinant to count weighted cycle systems in a directed graph

One method for counting weighted cycle systems in a graph entails taking the determinant of the identity matrix minus the adjacency matrix of the graph. The result of this operation is the sum over cycle systems of −1 to the power of the number of disjoint cycles times the weight of the cycle system. We use this fact to reprove that the determinant of a matrix of much smaller order can be computed to calculate the number of cycle systems in a hamburger graph.     

Global Analysis of Predator–Prey System with Hawk and Dove Tactics

Functional response of the Holling type II is incorporated into a predator–prey model with predators using hawk‐dove tactics to consider combination effects of nonlinear functional response and individual tactics. By mathematical analysis, it is shown that the model undergoes a sequence of bifurcations including saddle‐node bifurcation, supercritical Hopf bifurcation and homoclinic bifurcation. New phenomena are found that include the bistable coexistence of prey and predators in the form of a stable limit cycle and a stable positive equilibrium, the bistable coexistence of prey and predators in a large stable limit cycle that encloses three positive equilibria and a stable positive equilibrium within the cycle, and the bistable coexistence of two stable limit cycles.     

On powers of Stieltjes moment sequences,II

We consider the set of Stieltjes moment sequences, for which every positive power is again a Stieltjes moment sequence, and prove an integral representation of the logarithm of the moment sequence in analogy to the Lévy–Khintchine representation. We use the result to construct product convolution semigroups with moments of all orders and to calculate their Mellin transforms. As an application we construct a positive generating function for the orthonormal Hermite polynomials.     

Countable infinite sequence of attractors'' families for the simplest known equivariant chaotic flow

More than 30 new families of periodic and strange attractors for the simplest known equivariant chaotic jerk equation are studied. Inside each family, both periodic and chaotic attractors result from the subharmonic cascade of a limit cycle born by saddle-node bifurcation. Our numerical results provide clear evidence for the following conjecture: the 35 observed families are the first members of a countable infinite sequence. Furthermore, our simulations point out four power laws relating to the initial infinite sequence of saddle-node bifurcations.     

Generalized Büchi’s problem for algebraic functions and meromorphic functions

Büchi’s nth power problem asks is there a positive integer M such that any sequence ${(x_1^n,\ldots ,x_M^n)}$ of nth powers of integers with nth difference equal to n! is necessarily a sequence of nth powers of successive integers. In this paper, we study an analogue of this problem for meromorphic functions and algebraic functions.