Abstract:
Let
X = (
Xt,
t≥ 0) be a locally square integrable martingale with
Xo = 0. The predictable quadratic variation of
X is<
X,
X>
t. Using the strong approximation result for continuous time semimartignales, we prove that if the jumps of
X satisfy certain assumptions, the Chung law of the iterated logarithm for the locally square integrable martingale holds,that is \mathrmP\left(\liminf _t \rightarrow \infty \frac\sup _0 \leq s \leq t\left|X_s\right|\left(\langle X, X\rangle_t / \log \log (X, X\rangle_t\right)^1 / 2=\frac\pi\sqrt8\right)=1.