Averaging principle of SDE with small diffusion: Moderate deviations
Guillin, A.
Ann. Probab., Tome 31 (2003) no. 1, p. 413-443 / Harvested from Project Euclid
Consider the following stochastic differential equation in $\mathbb{R}^d$: \begin{eqnarray*} dX^\varepsilon_t &=& b(X_t^\varepsilon,\xi_{t/\varepsilon})\,dt +\sqrt{\varepsilon} a(X_t^\varepsilon,\xi_{t/\varepsilon})\,dW_t,\\ X^\varepsilon_0 &=& x_0, \end{eqnarray*} where the random environment $(\xi_t)$ is an exponentially ergodic Markov process, independent of the Wiener process $(W_t)$, with invariant probability measure $\pi$, and $\varepsilon$ is some small parameter. In this paper we prove the moderate deviations for the averaging principle of $X^\varepsilon$, that is, deviations of $(X^\varepsilon_t)$ around its limit averaging system $(\bar x_t)$ given by %$\bar{d}$. % $d\bar x_t=\bar b(\bar x_t)\,dt$ and $\bar x_0=x_0$ where $\bar b(x)=\mathbb{E}_\pi(b(x,\cdot))$. More precisely we obtain the large deviation estimation about \[ \Bigl(\eta^\varepsilon_t={X^\varepsilon_t-\bar x_t \over \sqrt{\varepsilon} h(\varepsilon)}\Big)_{t\in[0,1]} \] in the space of continuous trajectories, as $\varepsilon$ decreases to 0, where $h(\varepsilon)$ is some deviation scale satisfying $1\ll h(\varepsilon)\ll\varepsilon^{-1/2}$. Our strategy will be first to show the exponential tightness and then the local moderate deviation principle, which relies on some new method involving a conditional Schilder's theorem and a moderate deviation principle for inhomogeneous integral functionals of Markov processes, previously established by the author.
Publié le : 2003-01-14
Classification:  Moderate deviation,  averaging principle,  SDE with small diffusion,  Markov process,  exponential ergodicity,  60F10,  60J60,  60J25
@article{1046294316,
     author = {Guillin, A.},
     title = {Averaging principle of SDE with small diffusion: Moderate deviations},
     journal = {Ann. Probab.},
     volume = {31},
     number = {1},
     year = {2003},
     pages = { 413-443},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1046294316}
}
Guillin, A. Averaging principle of SDE with small diffusion: Moderate deviations. Ann. Probab., Tome 31 (2003) no. 1, pp.  413-443. http://gdmltest.u-ga.fr/item/1046294316/