Hausdorff Measure for a Stable-Like Process over an Infinite Extension of a Local Field

Abstract

We consider an infinite extension $K$ of a local field of zero characteristic which is a union of an increasing sequence of finite extensions. $K$ is equipped with an inductive limit topology; its conjugate $\bar{K}$ is a completion of $K$ with respect to a topology given by certain explicitly written seminorms. The semigroup of measures, which defines a stable-like process $X(t)$ on $\bar{K}$, is concentrated on a compact subgroup $S\subset \bar{K}$. We study properties of the process $X_S(t)$, a part of $X(t)$ in $S$. It is shown that the Hausdorff and packing dimensions of the image of an interval equal 0 almost surely. In the case of tamely ramified extensions a correct Hausdorff measure for this set is found.