Singularity Analysis for Heavy-Tailed Random Variables

Autor: Nicholas M. Ercolani, Daniel Ueltschi, Sabine Jansen
Rok vydání: 2018
Předmět:
Zdroj: Journal of Theoretical Probability. 32:1-46
ISSN: 1572-9230
0894-9840
DOI: 10.1007/s10959-018-0832-2
Popis: We propose a novel complex-analytic method for sums of i.i.d. random variables that are heavy-tailed and integer-valued. The method combines singularity analysis, Lindel\"of integrals, and bivariate saddle points. As an application, we prove three theorems on precise large and moderate deviations which provide a local variant of a result by S. V. Nagaev (1973). The theorems generalize five theorems by A. V. Nagaev (1968) on stretched exponential laws $p(k) = c\exp( -k^\alpha)$ and apply to logarithmic hazard functions $c\exp( - (\log k)^\beta)$, $\beta>2$; they cover the big jump domain as well as the small steps domain. The analytic proof is complemented by clear probabilistic heuristics. Critical sequences are determined with a non-convex variational problem.
Comment: 32 pages, 3 figures
Databáze: OpenAIRE