A generalization of the Pólya–Vinogradov inequality

In this paper we consider an approach of Dobrowolski and Williams which leads to a generalization of the Pólya–Vinogradov inequality. We show how the Dobrowolski–Williams approach is related to the classical proof of Pólya–Vinogradov using Fourier analysis. Our results improve upon the earlier work of Bachman and Rachakonda (Ramanujan J. 5:65–71, 2001). In passing, we also obtain sharper explicit versions of the Pólya–Vinogradov inequality.     

Type II bivariate Pólya–Aeppli distribution

In this paper, we introduce the Type II bivariate Pólya–Aeppli distribution as a compound Poisson distribution with bivariate geometric compounding distribution. The probability mass function, recursion formulas, conditional distributions and some other properties are then derived for this distribution.     

On the Time-Dependent Delta-Shock Model Governed by the Generalized PóLya Process

One of the widely discussed in the literature and relevant in practice shock models is the delta-shock model that is described by the constant time of a system’s recovery after a shock. However, in practice, as time progresses and due to deterioration of a system, this recovery time is gradually increasing. This important phenomenon was not discussed in the literature so far. Therefore, in this paper, we are considering a time-dependent delta-shock model, i.e., the recovery time becomes an increasing function of time. Moreover, we assume that shocks occur according to the generalized Pólya process that contains the homogeneous Poisson process, the non-homogeneous Poisson process and the Pólya process as particular cases. For the defined survival model, we derive the corresponding survival function and the mean lifetime and study the related optimal replacement policy along with some relevant stochastic properties.

     

The Pólya sum process: a Cox representation

In [1], Zessin constructed the so-called Pólya sum process via partial integration. Here we use the technique of integration by parts to the Pólya sum process to derive representations of the Pólya sum process as an infinitely divisible point process and a Cox process directed by an infinitely divisible random measure. This result is related to the question of the infinite divisibilty of a Cox process and the infinite divisibility of its directing measure. Finally we consider a scaling limit of the Pólya sum process and show that the limit satisfies an integration by parts formula, which we use to determine basic properties of this limit.     

The Pólya Sum Process: Limit Theorems for Conditioned Random Fields

Zessin (J. Contemp. Math. Anal. 44(1):36–44, 2009) constructed the so-called Pólya sum process via partial integration technique. This process shares some important properties with the Poisson process such as complete randomness and infinite divisibility. This work discusses H-sufficient statistics for the Pólya sum process as was done for the Poisson process by Nguyen and Zessin (Z. Wahrscheinlichkeitstheor. Verw. Geb. 37(3):191–200, 1976/77).     

A metric discrepancy result for the Hardy–Littlewood–Pólya sequences

The exact law of the iterated logarithm for discrepancies of the Hardy– Littlewood–Pólya sequences is proved. The exact constant in the law of the iterated logarithm is explicitly computed in the case when the Hardy–Littlewood–Pólya sequence consists of odd numbers.     

Convex symmetrization and Pólya–Szegö inequality

We prove a Pólya–Szegö inequality involving a convex symmetrization of functions and we investigate the equality case.     

Rearrangement inequalities in the discrete setting and some applications

We prove extended Hardy–Littlewood, Riesz and Pólya–Szeg? inequalities in the discrete case. We also establish cases of equality in these inqualities and give some applications of our result.     

Pólya分布在气候统计中的应用

Pólya分布在气候统计中常用来拟合雾、雷暴等.本文给出了Pólya分布总体在全样本场合下参数的矩估计和极大似然估计,并研究了估计的存在性,并通过大量的Monte Carlo模拟说明了估计的精度,认为在样本较大的情形下极大似然估计优于矩估计.最后通过具体的雾与雷暴等气候统计数据说明本文方法的可行性.     

Martingale characterization of Pólya processes and sequences

It is proved that a mixed Poisson process ξ_t is a Pólya process if and only if there exists a nondegenerate linear transform ξ_t → η_t = a(t)ξ_t + b(t) such that η_t is a martingale. A similar result is valid for Pólya sequences.     

Statistical modeling for discrete patterns in a sequence of exchangeable trials

This paper proposes a new method for constructing a sequence of infinitely exchangeable uniform random variables on the unit interval. For constructing the sequence, we utilize a Pólya urn partially. The resulting exchangeable sequence depends on the initial numbers of balls of the Pólya urn. We also derive the de Finetti measure for the exchangeable sequence. For an arbitrarily given one-dimensional distribution function, we generate sequences of exchangeable random variables with the one-dimensional marginal distribution by transforming the exchangeable uniform sequences with the inverse function of the distribution function. Among them we mainly investigate sequences of exchangeable discrete random variables. They differ from the well-known exchangeable sequence generated only by the Pólya urn scheme. Some examples are also given as applications of the results to exact distributions of some statistics based on sequences of exchangeable trials. Further, from the above exchangeable uniform sequence we construct partial or Markov exchangeable sequences. We also provide numerical examples of statistical inference based on the exchangeable and Markov exchangeable sequences.     

Equivalence between Pólya–Szegő and relative capacity inequalities under rearrangement

The transformations of functions acting on sublevel sets that satisfy a Pólya–Szeg? inequality are characterized as those being induced by transformations of sets that do not increase the associated capacity.     

Characterization and Enumeration of Certain Classes of Tenable Pólya Urns Grown by Drawing Multisets of Balls

We study necessary and sufficient conditions for the strong tenability of Pólya urn schemes under the sampling of multisets of balls. We also investigate sufficient conditions for the tenability (not necessarily in the strong sense) of Pólya urn schemes under the sampling of multisets of balls. We enumerate certain balanced classes and give algorithmic constructions for the replacement matrices for members in the class. We probabilistically analyze the zero-balanced tenable class, and find the asymptotic average proportion of each color, when the starting number of balls is large. We also give an algorithm to determine tenability and construct the Markov chain underlying the scheme, when it is tenable.     

The Pólya–Chebotarev problem and inverse polynomial images

Consider the problem, usually called the Pólya–Chebotarev problem, of finding a continuum in the complex plane including some given points such that the logarithmic capacity of this continuum is minimal. We prove that each connected inverse image ${\mathcal {T}}_{n}^{-1} ([-1,1])$ of a polynomial  ${\mathcal {T}}_{n}$ is always the solution of a certain Pólya–Chebotarev problem. By solving a nonlinear system of equations for the zeros of ${\mathcal {T}}_{n}^{2}-1$ , we are able to construct polynomials ${\mathcal {T}}_{n}$ with a connected inverse image.     

Computational Aspects of Optional Pólya Tree

Optional Pólya tree (OPT) is a flexible nonparametric Bayesian prior for density estimation. Despite its merits, the computation for OPT inference is challenging. In this article, we present time complexity analysis for OPT inference and propose two algorithmic improvements. The first improvement, named limited-lookahead optional Pólya tree (LL-OPT), aims at accelerating the computation for OPT inference. The second improvement modifies the output of OPT or LL-OPT and produces a continuous piecewise linear density estimate. We demonstrate the performance of these two improvements using simulated and real date examples.     

On Tabor groupoids and stability of some functional equations

Two results are given, which use Tabor groupoids for questions of stability in the sense of Pólya–Szeg?–Hyers–Ulam. We also start to study Tabor groupoids in their own right.     

Oscillation criteria for first and second order forced difference equations with mixed nonlinearities

Some new criteria for the oscillation of certain difference equations with mixed nonlinearities are established. The main tool in the proofs is an inequality due to Hardy, Littlewood, and Pólya.     

Pólya–Schur Inequality and the Green Energy of a Discrete Charge

Doklady Mathematics - The classical Pólya–Schur inequality for the logarithmic energy of a point charge distributed on a circle is generalized to the Green energy with respect to the...     

On Edgeworth Expansions in Generalized Urn Models

The random vector of frequencies in a generalized urn model can be viewed as conditionally independent random variables, given their sum. Such a representation is exploited here to derive Edgeworth expansions for a “sum of functions of such frequencies,” which are also called “decomposable statistics.” Applying these results to urn models such as with- and without-replacement sampling schemes as well as the multicolor Pólya–Egenberger model, new results are obtained for the chi-square statistic, for the sample sum in a without-replacement scheme, and for the so-called Dixon statistic that is useful in comparing two samples.     

On densities for solutions to stochastic fixed point equations

We consider systems of stochastic fixed point equations that arise in the asymptotic analysis of random recursive structures and algorithms such as Quicksort, large Pólya urn processes, and path lengths of random recursive trees and split trees. The main result states sufficient conditions on the fixed point equations that imply the existence of bounded, smooth, rapidly decreasing Lebesgue densities.