Central limit theorems for non-linear functionals of Gaussian fields

In the present paper it is shown that the central limit theorem holds for some non-linear functionals of stationary Gaussian fields if the correlation function of the underlying field tends fast enough to zero. The results are formulated in terms of the Hermite rank of the functional and of the rate of the correlation function. Then we show an example when the limit field is self-similar and Gaussian but not necessarily consisting of independent elements.     

Structure of the third moment of the generalized Rosenblatt distribution

The Rosenblatt distribution appears as limit in non-central limit theorems. The generalized Rosenblatt distribution is obtained by allowing different power exponents in the kernel that defines the usual Rosenblatt distribution. We derive an explicit formula for its third moment, correcting the one in Maejima and Tudor (2012) and Tudor (2013). Evaluating this formula numerically, we are able to confirm that the class of generalized Hermite processes is strictly richer than the class of Hermite processes.     

When bad things happen to good trees*

When the edges in a tree or rooted tree fail with a certain fixed probability, the (greedoid) rank may drop. We compute the expected rank as a polynomial in p and as a real number under the assumption of uniform distribution. We obtain several different expressions for this expected rank polynomial for both trees and rooted trees, one of which is especially simple in each case. We also prove two extremal theorems that determine both the largest and smallest values for the expected rank of a (rooted or unrooted) tree, and precisely when these extreme bounds are achieved. We conclude with directions for further study. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 79–99, 2001     

Central and Non-central Limit Theorems in a Free Probability Setting

Long-range dependence in time series may yield non-central limit theorems. We show that there are analogous time series in free probability with limits represented by multiple Wigner integrals, where Hermite processes are replaced by non-commutative Tchebycheff processes. This includes the non-commutative fractional Brownian motion and the non-commutative Rosenblatt process.     

Commutative cancellative semigroups of finite rank

The rank of a commutative cancellative semigroup S is the cardinality of a maximal independent subset of S. Commutative cancellative semigroups of finite rank are subarchimedean and thus admit a Tamura-like representation. We characterize these semigroups in several ways and provide structure theorems in terms of a construction akin to the one devised by T. Tamura for N-semigroups.     

修正高阶Hermite插值及Hermite-Fejer插值在L_ω～p空间中逼近的正逆定理(英文)

在L_ω～p空间中引入了一种 K-泛函并由此建立了一种以第一类 Chebyshev多项式的零点为结点的三种修正高阶 Hermite-Fejer插值多项式及一种修正的高阶 Hermite插值多项式在L_ω～p空间中逼近的正逆定理. 文中的结果说明,对于这几种修正高阶多项式插值的逼近问题而言,正定理的解决意味着逆定理的解决.     

Note on the Cantor–Bendixson Rank of Limit Groups

We show that the Cantor–Bendixson rank of a limit group is finite as well as that of a limit group of a linear group.     

Kapranov rank vs. tropical rank

We show that determining Kapranov rank of tropical matrices is not only NP-hard over any infinite field, but if solving Diophantine equations over the rational numbers is undecidable, then determining Kapranov rank over the rational numbers is also undecidable. We prove that Kapranov rank of tropical matrices is not bounded in terms of tropical rank, answering a question of Develin, Santos, and Sturmfels.

     

Confluent Vandermonde matrices,divided differences,and Lagrange–Hermite interpolation over quaternions

We introduce the notion of a confluent Vandermonde matrix with quaternion entries and discuss its connection with Lagrange–Hermite interpolation over quaternions. The formula for the rank of a confluent Vandermonde matrix is obtained as well as the representation formula for divided differences of quaternion polynomials. Extensions of these results to the power series setting include the formula for the rank of a confluent Cauchy matrix and norm-constrained Lagrange–Hermite interpolation by square summable power series over quaternions.     

A numerical approach to some basic theorems in singularity theory

In this paper, we give the explicit bounds for the data of objects involved in some basic theorems of singularity theory: the inverse, implicit and rank theorems for Lipschitz mappings, the splitting lemma and the Morse lemma, the density and openness of Morse functions. We expect that the results will make singularities more applicable and will be useful for numerical analysis and some fields of computing.     

On finite rank operators in CSL algebras II

For finite rank operators in a commutative subspace lattice algebra algℒ we introduce the concept of correlation matrices, basing on which we prove that a finite rank operator in algℒ can be written as a finite sum of rank-one operators in algℒ, if it has only finitely many different correlation matrices. Thus we can recapture the results of J.R. Ringrose, A. Hopenwasser and R.Moore as corollaries of our theorems. Research supported by NSF of China     

Tracial Limit of C^＊-algebras

A new limit of C^*-algebras, the tracial limit, is introduced in this paper. We show that a separable simple C^*-algebra A is a tracial limit of C^*-algebras in Z-(k) if and only if A has tracial topological rank no more than k. We present several known results using the notion of tracial limits.     

Unitary stable ranks and norm-one ranks

In the context of commutative C*-algebras, we solve a problem related to a question of M. Rieffel by showing that the all-units rank and the norm-one rank coincide with the topological stable rank. We also introduce the notion of unitary M-stable rank for an arbitrary commutative unital ring and compare it with the Bass stable rank. In case of uniform algebras, a su?cient condition for norm-one reducibility is given.     

Higher order recurrences and row sequences of Hermite–Padé approximation

ABSTRACT

We obtain extensions of the Poincaré and Perron theorems for higher order recurrence relations and apply them to obtain an inverse-type theorem for row sequences of the (type II) Hermite–Padé approximation of a vector of formal power series.     

用迹表示研究序列的线性复杂度

本文用迹表示式证明了序列的线性复杂度等于其秩矩阵的秩，并由此导出了正规基的计数公式．     

特殊Hermite展开的乘子定理

本文通过建立与特殊Hermite展开相对应的Littlewood-Paley分解和相关的扭曲卷积核的L2估计,得到特殊Hermite展开的乘子定理,作为该结果的应用,给出了Hermite函数及Laguerre函数展开的乘子定理。     

On the Generation of Some Embeddable GF(2) Geometries

The generating rank is determined for several GF(2)-embeddable geometries and it is demonstrated that their generating and embedding ranks are equal. Specifically, we prove that each of the two generalized hexagons of order (2, 2) has generating rank 14, that the central involution geometry of the Hall-Janko sporadic group has generating rank 28, and that the dual polar space DU(6,2) has generating rank 22. We also include a survey of all instances in which either the generating or embedding rank of an embeddable GF(2) geometry is known.     

A Characterization of Homogeneous Spaces with Positive Hyperbolic Rank

Here we present a necessary and sufficient condition for a negatively curved homogeneous space to be a rank one symmetric space. In particular, we show rigidity if such a space has positive hyperbolic rank greater than equal to that of its 'Abelian direction'. The notion of hyperbolic-rank extends the notion of rank in negatively curved spaces. The central theorem is an analogue of a result by U. Hamenstädt for compact negatively curved manifolds. We also provide an example of a nonsymmetric hyperbolic rank two homogeneous space, demonstrating the sharpness of the theorem.     

On Algebraic Curves whose Osculating Planes Belong to the Maximal Number of Independent Linear Complexes

We extend to higher Gaussian maps two classical theorems by Giuseppe Gherardelli and Beniamino Segre which give a sharp lower bound on the rank and characterize the borderline case.