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In mathematics, Doob's martingale inequality is a result in the study of stochastic processes. It gives a bound on the probability that a stochastic process exceeds any given value over a given interval of time. As the name suggests, the result is usually given in the case that the process is a non-negative martingale, but the result is also valid for non-negative submartingales. The inequality is due to the American mathematician Joseph L. Doob. ==Statement of the inequality== Let ''X'' be a submartingale taking non-negative real values, either in discrete or continuous time. That is, for all times ''s'' and ''t'' with ''s'' < ''t'', : (For a continuous-time submartingale, assume further that the process is càdlàg.) Then, for any constant ''C'' > 0 and ''p'' ≥ 1, : in the sense of Lebesgue integration. denotes the σ-algebra generated by all the random variables ''Xi'' with ''i'' ≤ ''s''; the collection of such σ-algebras forms a filtration of the probability space. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Doob's martingale inequality」の詳細全文を読む スポンサード リンク
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