Abstract
In this paper we prove the existence of the quadratic covariation [f(X),X], where f is a locally square integrable function and Xt = ∫t 0 u s dW s is a smooth nondegenerate Brownian martingale. This result is based on some moment estimates for Riemann sums which are established by means of the techniques of the Malliavin calculus.
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REFERENCES
Bardina, X., and Jolis, M. (1997). An extension of Itô's formula for elliptic diffusion processes. Stoch. Proc. Appl. 69, 83–109.
Bouleau, N., and Yor, M. (1981). Sur la variation quadratique des temps locaux de certaines semimartingales. C. R. Acad. Sci. Paris 292, 491–494.
Bouleau, N., and Hirsh, F. (1986). Propriétés d'absolute continuité dans les espaces de Dirichlet et applications aux équations différentielles stochastiques. In Séminaire de Probabilités XX, Lecture Notes in Math. 1204, 131–161.
Eisenbaum, N. (1997). Integration with respect to local time. Preprint.
Föllmer, H., Protter, Ph., and Shiryayev, A. N. (1995). Quadratic covariation and an extension of Itoô's formula. Bernouilli 1 (1–2), 149–169.
Föllmer, H., and Protter, Ph. (1997). On Itoô's formula for d-dimensional Brownian motion. Preprint.
Itoô, K. (1944). Stochastic integral. Proc. Imperial Acad. Tokyo 20, 519–524.
Nualart, D. (1998). Analysis on Wiener space and anticipating stochastic calculus. In: École d'été de Saint-Flour XXV (1995). Lect. Notes in Math. 1690, 123–227.
Nualart, D. (1995). Malliavin Calculus and Related Topics, Springer-Verlag.
Russo, F., and Vallois, P. (1994). Itoô's formula for C1 functions of semimartingales. Prob. Th. Rel. Fields 104 (1), 27–41.
Wolf, J. (1997a). An Itoô's formula for local Dirichlet processes. Stoch. Stoch. Rep. 62, 103–115.
Wolf, J. (1997b). Transformations on semimartingales and local Dirichlet processes. Stoch. Stoch. Rep. 62, 65–101.
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Moret, S., Nualart, D. Quadratic Covariation and Itô's Formula for Smooth Nondegenerate Martingales. Journal of Theoretical Probability 13, 193–224 (2000). https://doi.org/10.1023/A:1007791027791
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DOI: https://doi.org/10.1023/A:1007791027791