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On perpetuities with light tails

Probability 2026-01-14 v2

Abstract

In the paper we consider the asymptotics of logarithmic tails of a perpetuity R=dj=1Qjk=1j1Mk,(Mn,Qn)n=1\mboxarei.i.d.copiesof(M,Q),R \stackrel{d}{=}\sum_{j=1}^\infty Q_j \prod_{k=1}^{j-1}M_k,\qquad(M_n,Q_n)_{n=1}^\infty \mbox{ are i.i.d. copies of }(M,Q), in the case when P(M[0,1))=1\mathbb{P}(M\in[0,1))=1 and QQ has all exponential moments. If MM and QQ are independent, under regular variation assumptions, we find the precise asymptotics of logP(R>x)-\log\mathbb{P}(R>x) as xx\to\infty. Moreover, we deal with the case of dependent MM and QQ and give asymptotic bounds for logP(R>x)-\log\mathbb{P}(R>x). It turns out that dependence structure between MM and QQ has a significant impact on the asymptotic rate of logarithmic tails of RR. Such phenomenon is not observed in the case of heavy-tailed perpetuities.

Keywords

Cite

@article{arxiv.1711.08912,
  title  = {On perpetuities with light tails},
  author = {Bartosz Kołodziejek},
  journal= {arXiv preprint arXiv:1711.08912},
  year   = {2026}
}

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33 pages