Arbeitspapier

On Itô's formula for multidimensional Brownian motion

Consider a d-dimensional Brownian motion X (Xl, ... ,Xd ) and a function F which belongs locally to the Sobolev space W 1,2. We prove an extension of Ito's formula where the usual second order terms are replaced by the quadratic covariations [fk(X), Xkj involving the weak first partial derivatives fk of F. In particular we show that for any locally square-integrable function f the quadratic covariations [f(X), Xkj exist as limits in probability for any starting point, except for some polar set. The proof is based on new approximation results for forward and backward stochastic integrals.

Language
Englisch

Bibliographic citation
Series: SFB 373 Discussion Paper ; No. 2001,90

Classification
Wirtschaft
Subject
Ito's formula
Brownian motion
stochastic integrals
quadratic covariation
Dirichlet spaces
polar sets

Event
Geistige Schöpfung
(who)
Föllmer, Hans
Protter, Philip E.
Event
Veröffentlichung
(who)
Humboldt University of Berlin, Interdisciplinary Research Project 373: Quantification and Simulation of Economic Processes
(where)
Berlin
(when)
2001

Handle
URN
urn:nbn:de:kobv:11-10051072
Last update
10.03.2025, 11:41 AM CET

Data provider

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Object type

  • Arbeitspapier

Associated

  • Föllmer, Hans
  • Protter, Philip E.
  • Humboldt University of Berlin, Interdisciplinary Research Project 373: Quantification and Simulation of Economic Processes

Time of origin

  • 2001

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