Blumenthal's zero–one law

In the mathematical theory of probability, Blumenthal's zero–one law,[1] named after Robert McCallum Blumenthal, is a statement about the nature of the beginnings of right continuous Feller process. Loosely, it states that any right continuous Feller process on starting from deterministic point has also deterministic initial movement.

Statement

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Suppose that   is an adapted right continuous Feller process on a probability space   such that   is constant with probability one. Let  . Then any event in the germ sigma algebra   has either   or  

Generalization

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Suppose that   is an adapted stochastic process on a probability space   such that   is constant with probability one. If   has Markov property with respect to the filtration   then any event   has either   or   Note that every right continuous Feller process on a probability space   has strong Markov property with respect to the filtration  .

References

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  1. ^ Blumenthal, Robert M. (1957), "An extended Markov property", Transactions of the American Mathematical Society, 85 (1): 52–72, doi:10.1090/s0002-9947-1957-0088102-2, JSTOR 1992961, MR 0088102, Zbl 0084.13602