Abstract:
Let $(X,\mu,T)$ be an ergodic dynamic system and let $\xi=(C_1,C_2,\dots)$ be a discrete decomposition
of $X$. Conditions are considered for the existence almost everywhere of
$$
\lim_{n\to\infty}\frac1n|\log\mu(C_{\xi n}(x))|,
$$
where $C_{\xi n}(x)$ is the element of the decomposition $\xi^n=\xi\vee T\xi\vee\dots<T^{n-1}\xi$ containing $x$.
It is proved that the condition $H(\xi)<\infty$ is close to being necessary.
If $T$ is a Markov automorphism and $\xi$ is the decomposition into states,
then the limit exists, even if $H(\xi)=\infty$, and is equal to the entropy of the chain.