Dans cet article, nous considérons une équation différentielle stochastique multidimensionnelle dirigée par un mouvement brownien fractionnaire d'indice de Hurst H>1/3. Nous développons E[f(Xt)] par rapport à t, où on note X la solution de l'EDS et où f:ℝn→ℝ est une fonction régulière. Par rapport à F. Baudoin et L. Coutin, Stochastic Process. Appl. 117 (2007) 550-574, où le même problème est étudié, nous améliorons leur résultat dans trois directions différentes: nous traîtons le cas d'une équation avec dérive, nous paramétrons notre développement à l'aide d'arbres, ce qui le rend plus facile à utiliser, et nous proposons un contrôle plus fin du reste quand H>1/2.
In this article, we consider an n-dimensional stochastic differential equation driven by a fractional brownian motion with Hurst parameter H>1/3. We derive an expansion for E[f(Xt)] in terms of t, where X denotes the solution to the SDE and f:ℝn→ℝ is a regular function. Comparing to F. Baudoin and L. Coutin, Stochastic Process. Appl. 117 (2007) 550-574, where the same problem is studied, we provide an improvement in three different directions: we are able to consider equations with drift, we parametrize our expansion with trees, which makes it easier to use, and we obtain a sharp estimate of the remainder for the case H>1/2.
@article{AIHPB_2009__45_1_157_0, author = {Neuenkirch, A. and Nourdin, I. and R\"o\ss ler, A. and Tindel, S.}, title = {Trees and asymptotic expansions for fractional stochastic differential equations}, journal = {Annales de l'I.H.P. Probabilit\'es et statistiques}, volume = {45}, year = {2009}, pages = {157-174}, doi = {10.1214/07-AIHP159}, mrnumber = {2500233}, zbl = {1172.60017}, language = {en}, url = {http://dml.mathdoc.fr/item/AIHPB_2009__45_1_157_0} }
Neuenkirch, A.; Nourdin, I.; Rößler, A.; Tindel, S. Trees and asymptotic expansions for fractional stochastic differential equations. Annales de l'I.H.P. Probabilités et statistiques, Tome 45 (2009) pp. 157-174. doi : 10.1214/07-AIHP159. http://gdmltest.u-ga.fr/item/AIHPB_2009__45_1_157_0/
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