Adapted process


In the study of stochastic processes, an adapted process is one that cannot "see into the future". An informal interpretation is that X is adapted if and only if, for every realisation and every n, Xn is known at time n. The concept of an adapted process is essential, for instance, in the definition of the Itō integral, which only makes sense if the integrand is an adapted process.

Definition

Let
The process is said to be adapted to the filtration if the random variable is a -measurable function for each.

Examples

Consider a stochastic process X : × Ω → R, and equip the real line R with its usual Borel sigma algebra generated by the open sets.