English

Asymptotics for first-passage times of L\'evy processes and random walks

Probability 2007-12-06 v1

Abstract

We study the exact asymptotics for the distribution of the first time τx\tau_x a L\'evy process XtX_t crosses a negative level x-x. We prove that P(τx>t)V(x)P(Xt0)/t\mathbf P(\tau_x>t)\sim V(x)\mathbf P(X_t\ge 0)/t as tt\to\infty for a certain function V(x)V(x). Using known results for the large deviations of random walks we obtain asymptotics for P(τx>t)\mathbf P(\tau_x>t) explicitly in both light and heavy tailed cases. We also apply our results to find asymptotics for the distribution of the busy period in an M/G/1 queue.

Keywords

Cite

@article{arxiv.0712.0728,
  title  = {Asymptotics for first-passage times of L\'evy processes and random walks},
  author = {Denis Denisov and Vsevolod Shneer},
  journal= {arXiv preprint arXiv:0712.0728},
  year   = {2007}
}