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In probability theory a Brownian excursion process is a stochastic processes that is closely related to a Wiener process (or Brownian motion). Realisations of Brownian excursion processes are essentially just realizations of a Wiener process selected to satisfy certain conditions. In particular, a Brownian excursion process is a Wiener process conditioned to be positive and to take the value 0 at time 1. Alternatively, it is a Brownian bridge process conditioned to be positive. BEPs are important because, among other reasons, they naturally arise as the limit process of a number of conditional functional central limit theorems.〔Durrett, Iglehart: Functionals of Brownian Meander and Brownian Excursion, (1975)〕 ==Definition== A Brownian excursion process, , is a Wiener process (or Brownian motion) conditioned to be positive and to take the value 0 at time 1. Alternatively, it is a Brownian bridge process conditioned to be positive. Another representation of a Brownian excursion in terms of a Brownian motion process ''W'' (due to Paul Lévy and noted by Kiyoshi Itō and Henry P. McKean, Jr.〔Itô and McKean (1974, page 75)〕) is in terms of the last time that ''W'' hits zero before time 1 and the first time that Brownian motion hits zero after time 1:〔 : Let be the time that a Brownian bridge process achieves its minimum on (). Vervaat (1979) shows that : 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「Brownian excursion」の詳細全文を読む スポンサード リンク
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