2020/04/11 by Pavlyukevich, Ilya, Pilipenko, Andrey
#34A12 #34E10 #34F05 (Secondary) #60G51 #60H10 (Primary) 60F05 #FOS: Mathematics #Probability (math.PR)
paper · doi:10.48550/arxiv.2004.05421
Let A_±>0, β∈(0,1), and let Z(α) be a strictly α-stable Lévy process with the jump measure ν(d z)=(C+\mathbbI(0,∞)(z)+ C-\mathbbI(-∞,0)(z))|z|-1-α d z, α∈ (1,2), C_±≥ 0, C++C->0. The selection problem for the model stochastic differential equation d Xε=(A+\mathbbI[0,∞)( Xε) - A-\mathbbI(-∞,0)( Xε))| Xε|β d t +ε d Z(α) states that in the small noise limit ε→ 0, solutions Xε converge weakly to the maximal or minimal solutions of the limiting non-Lipschitzian ordinary differential equation d x=(A+\mathbbI[0,∞)( x)- A-\mathbbI(∞,0)( x))| x|β d t with probabilities p_±= p_±(α,C+/C-,β, A+/A-), see [Pilipenko and Proske, Stat. Probab. Lett., 132:62-73, 2018]. In this paper we solve the generalized selection problem for the stochastic differential equation d Xε=a(Xε) d t+ε b(Xε) d Z whose dynamics in the vicinity of the origin in certain sense reminds of dynamics of the model equation. In particular we show that solutions Xε also converge to the maximal or minimal solutions of the limiting irregular ordinary differential equation d x=a(x) d t with the same model selection probabilities p_±. This means that for a large class of irregular stochastic differential equations, the selection dynamics is completely determined by four local parameters of the drift and the jump measure.