Quasi-Regular Sequences and Regular Sequences

In this article, we give a comparison between the behavior of R-regular sequences under passage to quotient and to localization and that of R-quasi-regular sequences. On the other hand, we use these results to construct two examples of R-quasi-regular sequences which are not R-regular.     

Parity Encoding of Binary Sequences

The parity encoding of binary sequences, which is essentially the inverse operation to the differentiationof binary sequences, partitions the sequences into cycles of sequences. The spectrum of these cycles is shown tobe a fractal-like semi-infinite sequence of powers of 2, with the property that truncating it at the(n + 1)st term yields the cycle spectrum for the parity encoding of the n-bitbinary sequences. A simple and complete characterization of both the cycles and of the cycle spectrum isgiven.     

On Applications of Quasi-Monotone Sequences and Quasi Power Increasing Sequences

In this article, we prove a general theorem dealing with an application of quasi-f-power increasing sequences and δ-quasi monotone sequences. This theorem also includes some known and new results.     

Multivariate Sequences of Binomial Type

Using the notion of convolution of binomial sequences it is possible to show that Sheffer sequences, cross sequences, and Steffensen sequences are only mild generalizations of ordinary sequences of binomial type.     

Maps Preserving Moment Sequences

For any sequence s of real numbers, we consider the class \(\mathcal {L}\) of maps (from \(\mathbb {R}^{\mathbb {N}_0}\) to \(\mathbb {R}^{\mathbb {N}_0}\)) that linearly combine a finite or infinite number of elements of s to obtain the new values of the transformed sequence. We characterize those maps in \(\mathcal {L}\) that transform moment sequences into moment sequences in terms of the existence of a stochastic process fulfilling appropriate requirements. Then, well-known stochastic processes are used to construct significant examples of such preserving mappings. As application, we also show that some celebrated numerical sequences (including several important combinatorial sequences) are actually transformed moment sequences.     

Sequences generating permutations

Linear recurring sequences generating permutations of the elements of a finite ring are introduced and examined. A complete answer to the discussed problems is given for the second-order sequences over Z_M. The possibilities for applications are also discussed.     

递推数列极限的一种求法

讨论一类递推数列极限的计算问题,通过找出递推数列的通项并对其直接求极限,可省去其极限的存在性证明,从而简化求极限过程．     

由数列定义的函数

We construct real valued functions from infinite sequences. We also consider some properties of such functions and null sequences.     

On the Seneta Sequences

In this paper, we prove some properties of the Seneta sequences and functions, and in particular we prove a representation theorem in the Karamata sense for the sequences from the Seneta class SOc.     

弱Ⅰ序列的刻画

在文献[5]中,周才军定义了弱Ⅰ序列,并利用Koszul上同调和局部上同调的方法刻画了这种序列.本文利用Ext函子刻画了弱Ⅰ序列.     

用二维游动描述DNA系列

在文献中,DNA序列曾被描述为一维游动和三维游动.对前者,一个游动对应于多个DNA序列;对后者,游动和DNA序列一一对应.我们发现在三维游动(xn,yn,zn)中,由xn,yn和zn中任意有序的两个给出的二维游动已经与DNA序列一一对应,且余下的一维游动由该二维游动完全决定.因此,二维游动似乎是描述DNA序列最合适的模型.4个碱基A,C,G和T共有4 !=24个排序.每一个排序都给出DNA序列用二维游动的一种描述.两个游动(x'n,y'n)和(x"n,y"n)被看作是等价的,如果(x'n,y'n)=(εx"n,δy"n)或(εy"n,δx"n),这里ε=±1,且δ=±1.于是这24个类型的游动被分成三个等价类;它们的代表分别是(xn,yn),(yn,zn),和(xn,zn),这里(xn,yn,zn)正好是张和张的三维游动.     

DNA序列的分类

本文对 A题中给出的 DNA序列分类问题进行了讨论 .从“不同序列中碱基含量不同”入手建立了欧氏距离判别模型 ,马氏距离判别模型以及 Fisher准则判定模型 ;又从“不同序列中碱基位置不同”入手建立了利用序列相关知识的相关度分类判别算法 ,并进一步研究了带反馈的相关度分类判别算法 .对于题中所给的待分类的人工序列和自然序列 ,本文都一一作了分类 .接着 ,本文又对其它各种常见的分类算法进行了讨论 ,并着重从分类算法的稳定性上对几种方法作了比较 .     

关于渐近随机的GFSR序列的设计

Ｔｏｏｔｉｌｌ等人提出了一种渐近的随机Ｔａｕｓｗｏｒｔｈｅ序列,并给出了一个偶然发现的此种序列,但直到现在尚未有人提出一个寻求此种序列的系统性的方法,本文中我们将给出一种设计ＧＦＳＲ序 算法,所产生的序列近似地满足渐近随机性,我们的算法基于反复地运用由Ｆｕｓｈｉｍｉ提出的算法,由现在的算法所设计出来的序列不有一种附加的好处,即其十中抽一的序列也是近似地渐近随机的,文中给出了一些数字例子。     

Sequences of Ordered Sets and Catalan Numbers

We define the down sets (lower covers, respectively) sequence of an ordered set. We show that the number of down set sequences of an n-ordered set is equal to the n-th Catalan Number. We give a characterization of down sets sequences of an ordered set and another characterization of lower covers sequences of an ordered set.     

关于Bent序列构造的一点注记

本文讨论文献[4]给出的构造bent序列的方法,指出该方法可以通过对级联序列进行下标变换实现,从而大大增加了[4]中给出的由两个已知bent序列构造出的bent序列的个数。     

Hamburger Moment Sequences in Combinatorics

We show that many well-known counting coefficients in combinatorics are Hamburger moment sequences in certain unified approaches and that Hamburger moment sequences are infinitely convex. We introduce the concept of the q-Hamburger moment sequence of polynomials and present some examples of such sequences of polynomials. We also suggest some problems and conjectures.     

The Combinatorics of Polynomial Sequences

We present a combinatorial model for the several kinds of polynomial sequences of binomial type and develop many of the theorems about them from this model. In the first section, we present a prefab model for the binomial formula and the generating-function theorem. In Sec. 2, we introduce the notion of U-graph and give examples of binomial prefabs of U-graphs. The umbral composition of U-graphs provides an interpretation of umbral composition of polynomial sequences in Sees. 3 and 5. Rota's interpretation of the Stirling numbers of the first kind as sums of the Mobius function in the partition lattice inspired our model for inverse sequences of binomial type in Sec. 4. Section 6 contains combinatorial proofs of several operator-theoretic results. The actions of shift operators and delta operators are explained in set-theoretic terms. Finally, in Sec. 6 we give a model for cross sequences and Sheffer sequences which is consistent with their decomposition into sequences of binomial type. This provides an interpretation of shift-invariant operators. Of course, all of these interpretations require that the coefficients involved be integer and usually non-negative as well.     

递推数列的非线性表达式的构造

A type of nonlinear expressions of Lucas sequences are established inspired by Hsu [A nonlinear expression for Fibonacci numbers and its consequences.J.Math.Res.Appl.,2012,32(6):654–658].Using the relationships between the Lucas sequence and other linear recurring sequences satisfying the same recurrence relation of order 2,i.e.,the Horadam sequences,we may transfer the identities of Lucas sequences to the latter.     

$T_{2}(T)$的几乎可裂序列及几乎$\mathcal {D}$-可裂序列

The AR-quiver and derived equivalence are two important subjects in the representation theory of finite dimensional algebras, and for them there are two important research tools-AR-sequences and D-split sequences. So in order to study the representations of triangular matrix algebra T2 (T ) = T0TT where T is a finite dimensional algebra over a field, it is important to determine its AR-sequences and D-split sequences. The aim of this paper is to construct the right(left) almost split morphisms, irreducible morphisms, almost split sequences and D-split sequences of T2 (T) through the corresponding morphisms and sequences of T. Some interesting results are obtained.     

GMW序列的迹表示

研究了长度为2n-1的二元GMW序列的迹表示,用从F2n到F2的迹函数的和式给出了GMW序列的一种简洁的迹表示,并且通过这种迹表示得到了一种新的快速生成GMW序列的方法和一种求GMW序列的极小多项式的方法.最后,还证明了两个GMW序列具有相同极小多项式的一个充要条件.