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Anna Pósfai

Publications and source records attributed to Anna Pósfai.

3 recordsLinked to original sources
arXiv2010

Couplings for irregular combinatorial assemblies

When approximating the joint distribution of the component counts of a decomposable combinatorial structure that is `almost' in the logarithmic class, but nonetheless has irregular structure, it is useful to be able first to establish that the distribution of a certain sum of non-negative integer valued random variables is smooth. This distribution is not like the normal, and individual summands can contribute a non-trivial amount to the whole, so its smoothness is somewhat surprising. In this paper, we consider two coupling approaches to establishing the smoothness, and contrast the results that are obtained.

math.PR↗
arXiv2010

Approximation Theorems Related to the Coupon Collector's Problem

This Ph.D. thesis concerns the version of the classical coupon collector's problem, when a collector samples with replacement a set of $n\ge 2$ distinct coupons so that at each time any one of the $n$ coupons is drawn with the same probability $1/n$. For a fixed integer $m\in\{0,1,...,n-1\}$, the coupon collector's waiting time $W_{n,m}$ is the random number of draws the collector performs until he acquires $n-m$ distinct coupons for the first time. The basic goal of the thesis is to approximate the distribution of the coupon collector's appropriately centered and normalized waiting time with well-known measures with high accuracy, and in many cases prove asymptotic expansions for the related probability distribution functions and mass functions. The approximating measures are chosen from five different measure families. Three of them -- the Poisson distributions, the normal distributions and the Gumbel-like distributions -- are probability measure families whose members occur as limiting laws in the limit theorems concerning $W_{n,m}$. The other two approximating measure families are certain compound Poisson distributions and Poisson--Charlier signed measures.

math.PR↗