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JOURNALS // Diskretnaya Matematika // Archive

Diskr. Mat., 2020 Volume 32, Issue 3, Pages 24–37 (Mi dm1618)

This article is cited in 2 papers

Asymptotical local probabilities of lower deviations for branching process in random environment with geometric distributions of descendants

K. Yu. Denisov

Steklov Mathematical Institute of Russian Academy of Sciences, Moscow

Abstract: We consider local probabilities of lower deviations for branching process $Z_{n} = X_{n, 1} + \dotsb + X_{n, Z_{n-1}}$ in random environment $\eta$. We assume that $\eta$ is a sequence of independent identically distributed random variables and for fixed environment $\boldsymbol\eta$ the distributions of variables $X_{i,j}$ are geometric ones. We suppose that the associated random walk $S_n = \xi_1 + \dotsb + \xi_n$ has positive mean $\mu$ and satisfies left-hand Cramer's condition ${\mathbf E}\exp(h\xi_i) < \infty$ if $h^{-}<h<0$ for some $h^{-} < -1$. Under these assumptions, we find the asymptotic representation of local probabilities ${\mathbf P}\left( Z_n = \lfloor\exp\left(\theta n\right)\rfloor \right)$ for $\theta \in [\theta_1,\theta_2] \subset (\mu^-;\mu)$ for some non-negative $\mu^-$.

Keywords: branching processes, random environments, random walks, Cramer's condition, large deviations, local theorems.

UDC: 519.218.27

Received: 28.05.2020

DOI: 10.4213/dm1618


 English version:
Discrete Mathematics and Applications, 2022, 32:5, 313–323

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