Feller-continuous process

In mathematics, a Feller-continuous process is a continuous-time stochastic process for which the expected value of suitable statistics of the process at a given time in the future depend continuously on the initial condition of the process. The concept is named after Croatian-American mathematician William Feller.

Definition

Let X : [0, +∞) × Ω  Rn, defined on a probability space (Ω, Σ, P), be a stochastic process. For a point x  Rn, let Px denote the law of X given initial datum X0 = x, and let Ex denote expectation with respect to Px. Then X is said to be a Feller-continuous process if, for any fixed t  0 and any bounded, continuous and Σ-measurable function g : Rn  R, Ex[g(Xt)] depends continuously upon x.

Examples

  • Every process X whose paths are almost surely constant for all time is a Feller-continuous process, since then Ex[g(Xt)] is simply g(x), which, by hypothesis, depends continuously upon x.
  • Every Itô diffusion with Lipschitz-continuous drift and diffusion coefficients is a Feller-continuous process.
gollark: This "belt machine" thing looks like an interesting variation on stacks.
gollark: The important question in designing this sort of thing is simple: how much can I make palaiologos complain?
gollark: I'm thinking I might have a fixed 64KiB of memory because it fits neatly into two bytes.
gollark: As of now it is just stored as a string (in Lua that's a bytestring) and immutable.
gollark: Should I map the program code into memory, or not do that?

See also

References

  • Øksendal, Bernt K. (2003). Stochastic Differential Equations: An Introduction with Applications (Sixth ed.). Berlin: Springer. ISBN 3-540-04758-1. (See Lemma 8.1.4)
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.