Abstract
We give necessary and sufficient conditions for a d–dimensional Lévy process (Xt)t≥0 to be in the matrix normalised Feller (stochastic compactness) classes FC and FC0 as t ↓ 0. This extends earlier results of the authors concerning convergence of a Lévy process in ℝd to normality, as the time parameter tends to 0. It also generalises and transfers to the Lévy case classical results of Feller and Griffin concerning realand vector-valued random walks. The process (Xt) and its quadratic variation matrix together constitute a matrix-valued Lévy process, and, in a further extension, we show that the condition derived for the process itself also guarantees the stochastic compactness of the combined matrix-valued process. This opens the way to further investigations regarding self-normalised processes.
Original language | English |
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Article number | 69 |
Journal | Electronic Journal of Probability |
Volume | 23 |
DOIs | |
Publication status | Published - 2018 |