English

Exact asymptotics of component-wise extrema of two-dimensional Brownian motion

Probability 2020-03-09 v1

Abstract

We derive the exact asymptotics of P(supt0(X1(t)μ1t)>u, sups0(X2(s)μ2s)>u),  u, P\left( \sup_{t\ge 0} \Bigl( X_1(t) - \mu_1 t\Bigr)> u, \ \sup_{s\ge 0} \Bigl( X_2(s) - \mu_2 s\Bigr)> u \right), \ \ u\to\infty, where (X1(t),X2(s))t,s0(X_1(t),X_2(s))_{t,s\ge0} is a correlated two-dimensional Brownian motion with correlation ρ[1,1]\rho\in[-1,1] and μ1,μ2>0\mu_1,\mu_2>0. It appears that the play between ρ\rho and μ1,μ2\mu_1,\mu_2 leads to several types of asymptotics. Although the exponent in the asymptotics as a function of ρ\rho is continuous, one can observe different types of prefactor functions depending on the range of ρ\rho, which constitute a phase-type transition phenomena.

Keywords

Cite

@article{arxiv.2003.02954,
  title  = {Exact asymptotics of component-wise extrema of two-dimensional Brownian motion},
  author = {Krzysztof Debicki and Lanpeng Ji and Tomasz Rolski},
  journal= {arXiv preprint arXiv:2003.02954},
  year   = {2020}
}