Seminar on Probability and Statistics

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Organizer(s) Nakahiro Yoshida, Teppei Ogihara, Yuta Koike

2009/12/21

15:00-16:10   Room #128 (Graduate School of Math. Sci. Bldg.)
Thomas Simon (Universite de Lille 1)
Absolute continuity of Ornstein-Uhlenbeck processes
[ Abstract ]
Let X be a multidimensional Ornstein-Uhlenbeck process, solution to the S.D.E.

dX = AX + dB

where A is a real nxn matrix and B a Lévy process. We show that when A is non-singular, the law of X_1 is absolutely continuous if and only if the jumping measure of B fulfils a certain geometric condition with respect to A and the Gaussian part of B, which we call the exhaustion property. This optimal criterion is much weaker than for B, which might be very singular and genuinely one-dimensional. The proof uses a certain time derivation procedure and basic arguments from controllability theory.
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2009/13.html