{"title":"First passage time and inverse problem for continuous local martingales","authors":"Yoann Potiron","doi":"10.1016/j.jspi.2026.106376","DOIUrl":null,"url":null,"abstract":"<div><div>This paper derives an explicit formula for the probability that a continuous local martingale crosses a one or two-sided random constant boundary for a finite time interval. The boundary crossing probability of a continuous local martingale to a constant boundary is equal to the boundary crossing probability of a standard Wiener process, which is time-changed by the martingale quadratic variation, to a constant boundary. This paper also derives an explicit solution to the inverse first passage time problem of quadratic variation. These results are obtained by an application of the Dambis, Dubins–Schwarz theorem. The main elementary idea of the proof is the scale invariant property of the time-changed Wiener process and thus the scale invariant property of the first passage time. This is due to the constancy of the boundary.</div></div>","PeriodicalId":50039,"journal":{"name":"Journal of Statistical Planning and Inference","volume":"243 ","pages":"Article 106376"},"PeriodicalIF":0.8000,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Statistical Planning and Inference","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0378375826000042","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/1/19 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"STATISTICS & PROBABILITY","Score":null,"Total":0}
引用次数: 0
Abstract
This paper derives an explicit formula for the probability that a continuous local martingale crosses a one or two-sided random constant boundary for a finite time interval. The boundary crossing probability of a continuous local martingale to a constant boundary is equal to the boundary crossing probability of a standard Wiener process, which is time-changed by the martingale quadratic variation, to a constant boundary. This paper also derives an explicit solution to the inverse first passage time problem of quadratic variation. These results are obtained by an application of the Dambis, Dubins–Schwarz theorem. The main elementary idea of the proof is the scale invariant property of the time-changed Wiener process and thus the scale invariant property of the first passage time. This is due to the constancy of the boundary.
期刊介绍:
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