{ "id": "1702.03917", "version": "v1", "published": "2017-02-13T18:46:38.000Z", "updated": "2017-02-13T18:46:38.000Z", "title": "MEXIT: Maximal un-coupling times for Markov processes", "authors": [ "P. A. Ernst", "W. S. Kendall", "G. O. Roberts", "J. S. Rosenthal" ], "comment": "23 pages, 2 figures", "categories": [ "math.PR" ], "abstract": "Classical coupling constructions arrange for copies of the \\emph{same} Markov process started at two \\emph{different} initial states to become equal as soon as possible. In this paper, we consider an alternative coupling framework in which one seeks to arrange for two \\emph{different} Markov processes to remain equal for as long as possible, when started in the \\emph{same} state. We refer to this \"un-coupling\" or \"maximal agreement\" construction as \\emph{MEXIT}, standing for \"maximal exit\" time. After highlighting the importance of un-coupling arguments in a few key statistical and probabilistic settings, we develop an explicit MEXIT construction for Markov chains in discrete time with countable state-space. This construction is generalized to random processes on general state-space running in continuous time, and then exemplified by discussion of MEXIT for Brownian motions with two different constant drifts.", "revisions": [ { "version": "v1", "updated": "2017-02-13T18:46:38.000Z" } ], "analyses": { "subjects": [ "60J60", "60G05" ], "keywords": [ "markov process", "maximal un-coupling times", "explicit mexit construction", "probabilistic settings", "initial states" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }