Skorokhod's representation theorem

In mathematics and statistics, Skorokhod's representation theorem is a result that shows that a weakly convergent sequence of probability measures whose limit measure is sufficiently well-behaved can be represented as the distribution/law of a pointwise convergent sequence of random variables defined on a common probability space. It is named for the Ukrainian mathematician A. V. Skorokhod.

Statement

Let (\mu_n)_{n \in \mathbb{N}} be a sequence of probability measures on a metric space S such that \mu_n converges weakly to some probability measure \mu_\infty on S as n \to \infty. Suppose also that the support of \mu_\infty is separable. Then there exist S-valued random variables X_n defined on a common probability space (\Omega,\mathcal{F},\mathbf{P}) such that the law of X_n is \mu_n for all n (including n=\infty) and such that (X_n)_{n \in \mathbb{N}} converges to X_\infty, \mathbf{P}-almost surely.

See also

References

  • {{cite book | last=Billingsley | first=Patrick | title=Convergence of Probability Measures | url=https://archive.org/details/convergenceofpro0000bill | url-access=registration | publisher=John Wiley & Sons, Inc. | location=New York | year=1999 | isbn = 0-471-19745-9}} (see p. 7 for weak convergence, p. 24 for convergence in distribution and p. 70 for Skorokhod's theorem)

Category:Theorems in probability theory

Category:Theorems in statistics