Nous établissons des vitesses fines de convergence presque sûre pour les approximations des chemins rugueux Gaussiens, sous l’hypothèse que la fonction de covariance du processus Gaussien sous-jacent ait une -variation finie, . Dans le cas du mouvement Brownien, respectivement du Brownien fractionnaire (fBM), pour lesquels resp. , ce résultat généralise les résultats respectifs de (Trans. Amer. Math. Soc. 361 (2009) 2689-2718) et (Ann. Inst. Henri Poincasé Probab. Stat. 48 (2012) 518-550). Notamment, nous établissons le taux de convergence presque sure , tout , pour les approximations de Wong-Zakai et de type Milstein avec pas de discrétisation . Dans le cas du fBM, ce résultat résout une conjecture posée par les références ci-dessus.
Under the key assumption of finite -variation, , of the covariance of the underlying Gaussian process, sharp a.s. convergence rates for approximations of Gaussian rough paths are established. When applied to Brownian resp. fractional Brownian motion (fBM), resp. , we recover and extend the respective results of (Trans. Amer. Math. Soc. 361 (2009) 2689-2718) and (Ann. Inst. Henri Poincasé Probab. Stat. 48 (2012) 518-550). In particular, we establish an a.s. rate , any , for Wong-Zakai and Milstein-type approximations with mesh-size . When applied to fBM this answers a conjecture in the afore-mentioned references.
@article{AIHPB_2014__50_1_154_0,
author = {Friz, Peter and Riedel, Sebastian},
title = {Convergence rates for the full gaussian rough paths},
journal = {Annales de l'I.H.P. Probabilit\'es et statistiques},
volume = {50},
year = {2014},
pages = {154-194},
doi = {10.1214/12-AIHP507},
mrnumber = {3161527},
zbl = {1295.60045},
language = {en},
url = {http://dml.mathdoc.fr/item/AIHPB_2014__50_1_154_0}
}
Friz, Peter; Riedel, Sebastian. Convergence rates for the full gaussian rough paths. Annales de l'I.H.P. Probabilités et statistiques, Tome 50 (2014) pp. 154-194. doi : 10.1214/12-AIHP507. http://gdmltest.u-ga.fr/item/AIHPB_2014__50_1_154_0/
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