Abstract:
Let $Z^{(k)}=\{ Z_i^{(k)},\, i=0,1,\dots\}$, $k=1,2,\dots$, be a sequence of
critical branching processes in random environment, which differ from one
another only in the population size $k$ of the initial generation. Suppose
that the variance $\sigma^2$ of the step of the associated random walk is
finite and positive. We fix $x\in (0,+\infty)$ and define
$Z^{(n,x)}=Z^{(m_n(x))}$, where $m_1(x),m_2(x),\dots$ is a sequence of
natural numbers, and $\ln m_n(x) \sim \sigma \sqrt{n}\, x$ as $n\to\infty$.
We prove limit theorems on the extinction moment of the process $Z^{(n,x)}$,
on the time-continuous normalized process constructed from $Z^{(n,x)}$, and
on the normalized logarithm of the process $Z^{(n,x)}$.
Keywords:critical branching process in random environment, limit theorem,
functional limit theorem.