Pub Date : 2026-05-01Epub Date: 2026-02-05DOI: 10.1016/j.spa.2026.104901
Johannes Assefa, Martin Keller-Ressel
We derive a moment formula for generalized fractional polynomial processes, i.e., for polynomial-preserving Markov processes time-changed by an inverse Lévy-subordinator. If the time change is inverse α-stable, the time-derivative of the Kolmogorov backward equation is replaced by a Caputo fractional derivative of order α, and we demonstrate that moments of such processes are computable, in a closed form, using matrix Mittag-Leffler functions. The same holds true for cross-moments in equilibrium, generalizing results of Leonenko, Meerschaert and Sikorskii from the one-dimensional diffusive case of second-order moments to the multivariate, jump-diffusive case of moments of arbitrary order. We show that also in this more general setting, fractional polynomial processes exhibit long-range dependence, with correlations decaying as a power law with exponent α.
{"title":"Moments of generalized fractional polynomial processes","authors":"Johannes Assefa, Martin Keller-Ressel","doi":"10.1016/j.spa.2026.104901","DOIUrl":"10.1016/j.spa.2026.104901","url":null,"abstract":"<div><div>We derive a moment formula for generalized fractional polynomial processes, i.e., for polynomial-preserving Markov processes time-changed by an inverse Lévy-subordinator. If the time change is inverse <em>α</em>-stable, the time-derivative of the Kolmogorov backward equation is replaced by a Caputo fractional derivative of order <em>α</em>, and we demonstrate that moments of such processes are computable, in a closed form, using matrix Mittag-Leffler functions. The same holds true for cross-moments in equilibrium, generalizing results of Leonenko, Meerschaert and Sikorskii from the one-dimensional diffusive case of second-order moments to the multivariate, jump-diffusive case of moments of arbitrary order. We show that also in this more general setting, fractional polynomial processes exhibit long-range dependence, with correlations decaying as a power law with exponent <em>α</em>.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104901"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-30DOI: 10.1016/j.spa.2026.104896
Apolline Louvet , Bastian Wiederhold
We propose a new stochastic epidemiological model defined in a continuous space of arbitrary dimension, based on SIS dynamics implemented in a spatial Λ-Fleming-Viot (SLFV) process. The model can be described by as little as three parameters, and is dual to a spatial branching process with competition linked to genealogies of infected individuals. Therefore, it is a possible modelling framework to develop computationally tractable inference tools for epidemics in a continuous space using demographic and genetic data.
We provide mathematical constructions of the process based on well-posed martingale problems as well as driving space-time Poisson point processes. With these devices and the duality relation in hand, we unveil some of the drivers of the transition between extinction and survival of the epidemic. In particular, we show that extinction is in large parts independent of the initial condition, and identify a strong candidate for the reproduction number R0 of the epidemic in such a model.
{"title":"A new stochastic SIS-type modelling framework for analysing epidemic dynamics in continuous space","authors":"Apolline Louvet , Bastian Wiederhold","doi":"10.1016/j.spa.2026.104896","DOIUrl":"10.1016/j.spa.2026.104896","url":null,"abstract":"<div><div>We propose a new stochastic epidemiological model defined in a continuous space of arbitrary dimension, based on SIS dynamics implemented in a spatial Λ-Fleming-Viot (SLFV) process. The model can be described by as little as three parameters, and is dual to a spatial branching process with competition linked to genealogies of infected individuals. Therefore, it is a possible modelling framework to develop computationally tractable inference tools for epidemics in a continuous space using demographic and genetic data.</div><div>We provide mathematical constructions of the process based on well-posed martingale problems as well as driving space-time Poisson point processes. With these devices and the duality relation in hand, we unveil some of the drivers of the transition between extinction and survival of the epidemic. In particular, we show that extinction is in large parts independent of the initial condition, and identify a strong candidate for the reproduction number R<sub>0</sub> of the epidemic in such a model.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104896"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-16DOI: 10.1016/j.spa.2026.104889
Federico Girotti, Alessandro Vitale
In this work we exhibit a class of examples that show that the characterization of purification of quantum trajectories in terms of ‘dark’ subspaces that was proved for finite dimensional systems (Infin. Dimens. Anal. Quantum Probab. Relat. Top., 06(02), 223-243, 2003 and IMS Lectures Notes-Monograph Series, 48, 252-261, 2006) fails to hold in infinite dimensional ones. Moreover, we prove that the new phenomenon emerging in our class of models and preventing purification to happen is the only new possibility that appears in infinite dimensional systems. Our proof strategy points out that the presence of new phenomena in infinite dimensional systems is due to the fact that the set of orthogonal projections is not sequentially compact. Having in mind this insight, we are able to prove that the finite dimensional result extends to a class of infinite dimensional models.
{"title":"Purification of quantum trajectories in infinite dimensions","authors":"Federico Girotti, Alessandro Vitale","doi":"10.1016/j.spa.2026.104889","DOIUrl":"10.1016/j.spa.2026.104889","url":null,"abstract":"<div><div>In this work we exhibit a class of examples that show that the characterization of purification of quantum trajectories in terms of ‘dark’ subspaces that was proved for finite dimensional systems (<em>Infin. Dimens. Anal. Quantum Probab. Relat. Top.</em>, 06(02), 223-243, 2003 and <em>IMS Lectures Notes-Monograph Series</em>, 48, 252-261, 2006) fails to hold in infinite dimensional ones. Moreover, we prove that the new phenomenon emerging in our class of models and preventing purification to happen is the only new possibility that appears in infinite dimensional systems. Our proof strategy points out that the presence of new phenomena in infinite dimensional systems is due to the fact that the set of orthogonal projections is not sequentially compact. Having in mind this insight, we are able to prove that the finite dimensional result extends to a class of infinite dimensional models.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104889"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-09DOI: 10.1016/j.spa.2026.104873
Rajat Subhra Hazra, Frank den Hollander, Azadeh Parvaneh
In [1] we analysed the friendship paradox for sparse random graphs. For four classes of random graphs we characterised the empirical distribution of the friendship biases between vertices and their neighbours at distance 1, proving convergence as n → ∞ to a limiting distribution, with n the number of vertices, and identifying moments and tail exponents of the limiting distribution. In the present paper we look at the multi-level friendship bias between vertices and their neighbours at distance obtained via a k-step exploration according to a backtracking or a non-backtracking random walk. We identify the limit of the empirical distribution of the multi-level friendship biases as n → ∞ and/or k → ∞. We show that for non-backtracking exploration the two limits commute for a large class of sparse random graphs, including those that locally converge to a rooted Galton-Watson tree. In particular, we show that the same limit arises when k depends on n, i.e., , provided under some mild conditions. We exhibit cases where the two limits do not commute and show the relevance of the mixing time of the exploration.
{"title":"The multi-level friendship paradox for sparse random graphs","authors":"Rajat Subhra Hazra, Frank den Hollander, Azadeh Parvaneh","doi":"10.1016/j.spa.2026.104873","DOIUrl":"10.1016/j.spa.2026.104873","url":null,"abstract":"<div><div>In [1] we analysed the friendship paradox for sparse random graphs. For four classes of random graphs we characterised the empirical distribution of the friendship biases between vertices and their neighbours at distance 1, proving convergence as <em>n</em> → ∞ to a limiting distribution, with <em>n</em> the number of vertices, and identifying moments and tail exponents of the limiting distribution. In the present paper we look at the multi-level friendship bias between vertices and their neighbours at distance <span><math><mrow><mi>k</mi><mo>∈</mo><mi>N</mi></mrow></math></span> obtained via a <em>k</em>-step exploration according to a backtracking or a non-backtracking random walk. We identify the limit of the empirical distribution of the multi-level friendship biases as <em>n</em> → ∞ and/or <em>k</em> → ∞. We show that for non-backtracking exploration the two limits commute for a large class of sparse random graphs, including those that locally converge to a rooted Galton-Watson tree. In particular, we show that the same limit arises when <em>k</em> depends on <em>n</em>, i.e., <span><math><mrow><mi>k</mi><mo>=</mo><msub><mi>k</mi><mi>n</mi></msub></mrow></math></span>, provided <span><math><mrow><msub><mi>lim</mi><mrow><mi>n</mi><mo>→</mo><mi>∞</mi></mrow></msub><msub><mi>k</mi><mi>n</mi></msub><mo>=</mo><mi>∞</mi></mrow></math></span> under some mild conditions. We exhibit cases where the two limits do not commute and show the relevance of the mixing time of the exploration.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104873"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-29DOI: 10.1016/j.spa.2026.104893
Kazuo Yamazaki
We study the two-dimensional magnetohydrodynamics system forced by space-time white noise. Due to a lack of an explicit invariant measure, the approach of Da Prato and Debussche (2002, J. Funct. Anal., 196, pp. 180–210) on the Navier-Stokes equations does not seem to fit. We follow instead the approach of Hairer and Rosati (2024, Ann. PDE, 10, pp. 1–46), take advantage of the structure of Maxwell’s equation, such as anti-symmetry, to find an appropriate paracontrolled ansatz and many crucial cancellations, and prove the global-in-time existence and uniqueness of its solution.
研究了时空白噪声作用下的二维磁流体动力学系统。由于缺乏明确的不变测度,Da Prato和Debussche (2002, J. Funct。分析的。(第196页,第180-210页)关于Navier-Stokes方程似乎不合适。相反,我们遵循海勒和罗萨蒂(2024,安。PDE, 10, pp. 1-46),利用麦克斯韦方程的反对称等结构,找到了一个合适的副控制解和许多关键的消去,并证明了其解的全局存在唯一性。
{"title":"Remarks on the two-dimensional magnetohydrodynamics system forced by space-time white noise","authors":"Kazuo Yamazaki","doi":"10.1016/j.spa.2026.104893","DOIUrl":"10.1016/j.spa.2026.104893","url":null,"abstract":"<div><div>We study the two-dimensional magnetohydrodynamics system forced by space-time white noise. Due to a lack of an explicit invariant measure, the approach of Da Prato and Debussche (2002, J. Funct. Anal., <strong>196</strong>, pp. 180–210) on the Navier-Stokes equations does not seem to fit. We follow instead the approach of Hairer and Rosati (2024, Ann. PDE, <strong>10</strong>, pp. 1–46), take advantage of the structure of Maxwell’s equation, such as anti-symmetry, to find an appropriate paracontrolled ansatz and many crucial cancellations, and prove the global-in-time existence and uniqueness of its solution.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104893"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-16DOI: 10.1016/j.spa.2026.104886
Kaustav Das , Ivan Guo , Grégoire Loeper
The price of a financial derivative can be expressed as an iterated conditional expectation, where the inner term conditions on the future of an auxiliary process. We show that this inner conditional expectation solves an SPDE (a ‘conditional Feynman-Kac formula’). The problem requires conditioning on a backward filtration generated by the noise of the auxiliary process and enlarged by its terminal value, leading us to search for a backward Brownian motion here. This adds a source of irregularity to the SPDE which we tackle with new techniques. Lastly, we establish a new class of mixed Monte-Carlo PDE numerical methods.
{"title":"On stochastic partial differential equations and their applications to derivative pricing through a conditional Feynman-Kac formula","authors":"Kaustav Das , Ivan Guo , Grégoire Loeper","doi":"10.1016/j.spa.2026.104886","DOIUrl":"10.1016/j.spa.2026.104886","url":null,"abstract":"<div><div>The price of a financial derivative can be expressed as an iterated conditional expectation, where the inner term conditions on the future of an auxiliary process. We show that this inner conditional expectation solves an SPDE (a ‘conditional Feynman-Kac formula’). The problem requires conditioning on a backward filtration generated by the noise of the auxiliary process and enlarged by its terminal value, leading us to search for a backward Brownian motion here. This adds a source of irregularity to the SPDE which we tackle with new techniques. Lastly, we establish a new class of mixed Monte-Carlo PDE numerical methods.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104886"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-14DOI: 10.1016/j.spa.2026.104887
A. Pedicone, E. Orsingher
In this paper we study the telegraph meander, a random function obtained by conditioning the telegraph process to stay above the zero level. The finite dimensional distribution of the telegraph meander is derived by applying the reflection principle for the telegraph process and the Markovianity of the telegraph process with the velocity process. We show that the law of the telegraph meander at the end time is a solution to a hyperbolic equation, and we find the characteristic function and moments of any order. Finally, we prove that Brownian meander is the weak limit of the telegraph meander.
{"title":"On the distribution of the telegraph meander and its properties","authors":"A. Pedicone, E. Orsingher","doi":"10.1016/j.spa.2026.104887","DOIUrl":"10.1016/j.spa.2026.104887","url":null,"abstract":"<div><div>In this paper we study the telegraph meander, a random function obtained by conditioning the telegraph process to stay above the zero level. The finite dimensional distribution of the telegraph meander is derived by applying the reflection principle for the telegraph process and the Markovianity of the telegraph process with the velocity process. We show that the law of the telegraph meander at the end time is a solution to a hyperbolic equation, and we find the characteristic function and moments of any order. Finally, we prove that Brownian meander is the weak limit of the telegraph meander.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104887"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-05DOI: 10.1016/j.spa.2026.104869
Feng-Yu Wang , Bingyao Wu , Jie-Xiang Zhu
In this paper we study the long time behavior in Wasserstein distance for empirical measures of (non-symmetric) diffusion processes on a length space satisfying the Nash inequality, which in particular include the (reflecting) diffusion processes on a connected compact Riemannian manifold. As a general result, the sharp convergence rate in for the p-Wasserstein distance is derived uniformly in p ∈ [1, ∞) and q ∈ (0, ∞). A key novelty of our approach, compared to existing works, is the use of a Bernstein-type inequality for diffusion processes.
{"title":"Sharp Lq-convergence rate in p-Wasserstein distance for empirical measures of diffusion processes","authors":"Feng-Yu Wang , Bingyao Wu , Jie-Xiang Zhu","doi":"10.1016/j.spa.2026.104869","DOIUrl":"10.1016/j.spa.2026.104869","url":null,"abstract":"<div><div>In this paper we study the long time behavior in Wasserstein distance for empirical measures of (non-symmetric) diffusion processes on a length space satisfying the Nash inequality, which in particular include the (reflecting) diffusion processes on a connected compact Riemannian manifold. As a general result, the sharp convergence rate in <span><math><mrow><msup><mi>L</mi><mi>q</mi></msup><mrow><mo>(</mo><mi>P</mi><mo>)</mo></mrow></mrow></math></span> for the <em>p</em>-Wasserstein distance is derived uniformly in <em>p</em> ∈ [1, ∞) and <em>q</em> ∈ (0, ∞). A key novelty of our approach, compared to existing works, is the use of a Bernstein-type inequality for diffusion processes.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104869"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-14DOI: 10.1016/j.spa.2026.104884
Zhang Chen , Bixiang Wang , Dandan Yang
This paper is concerned with the limiting behavior of the fractional stochastic reaction-diffusion equations defined in a sequence of open balls of radius k in . Under certain conditions, we prove that every weak limit point of invariant measures of the equations defined in Ok must be an invariant measure of the equation defined on as k → ∞. We also prove the convergence of invariant measures of the equations in Ok in terms of the Wasserstein metric and derive the rate of such convergence as k → ∞. The uniform tail-ends estimates of solutions are employed to overcome the non-compactness of Sobolev embeddings on .
{"title":"Limiting behavior of invariant measures of fractional stochastic reaction-diffusion equations on expanding domains","authors":"Zhang Chen , Bixiang Wang , Dandan Yang","doi":"10.1016/j.spa.2026.104884","DOIUrl":"10.1016/j.spa.2026.104884","url":null,"abstract":"<div><div>This paper is concerned with the limiting behavior of the fractional stochastic reaction-diffusion equations defined in a sequence <span><math><msubsup><mrow><mo>{</mo><msub><mi>O</mi><mi>k</mi></msub><mo>}</mo></mrow><mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow><mi>∞</mi></msubsup></math></span> of open balls of radius <em>k</em> in <span><math><msup><mi>R</mi><mi>n</mi></msup></math></span>. Under certain conditions, we prove that every weak limit point of invariant measures of the equations defined in <em>O<sub>k</sub></em> must be an invariant measure of the equation defined on <span><math><msup><mi>R</mi><mi>n</mi></msup></math></span> as <em>k</em> → ∞. We also prove the convergence of invariant measures of the equations in <em>O<sub>k</sub></em> in terms of the Wasserstein metric and derive the rate of such convergence as <em>k</em> → ∞. The uniform tail-ends estimates of solutions are employed to overcome the non-compactness of Sobolev embeddings on <span><math><msup><mi>R</mi><mi>n</mi></msup></math></span>.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104884"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-10DOI: 10.1016/j.spa.2026.104874
Hanwu Li , Huilin Zhang , Kuan Zhang
In this paper, we investigate reflected backward stochastic differential equations driven by rough paths (rough RBSDEs), which can be viewed as probabilistic representations of nonlinear rough partial differential equations (rough PDEs) or stochastic partial differential equations (SPDEs) with obstacles. Furthermore, we demonstrate that solutions to rough RBSDEs solve the corresponding optimal stopping problems within a rough framework. This development provides effective and practical tools for pricing American options in the context of the rough volatility model, thus playing a crucial role in advancing the understanding and application of option pricing in complex market regimes.
The well-posedness of rough RBSDEs is established using a variant of the Doss-Sussmann transformation. Moreover, we show that rough RBSDEs can be approximated by a sequence of penalized BSDEs with rough drivers. For applications, we first develop the viscosity solution theory for rough PDEs with obstacles via rough RBSDEs. Second, we solve the corresponding optimal stopping problem and establish its connection with an American option pricing problem in the rough path setting.
{"title":"Reflected backward stochastic differential equations with rough drivers","authors":"Hanwu Li , Huilin Zhang , Kuan Zhang","doi":"10.1016/j.spa.2026.104874","DOIUrl":"10.1016/j.spa.2026.104874","url":null,"abstract":"<div><div>In this paper, we investigate reflected backward stochastic differential equations driven by rough paths (rough RBSDEs), which can be viewed as probabilistic representations of nonlinear rough partial differential equations (rough PDEs) or stochastic partial differential equations (SPDEs) with obstacles. Furthermore, we demonstrate that solutions to rough RBSDEs solve the corresponding optimal stopping problems within a rough framework. This development provides effective and practical tools for pricing American options in the context of the rough volatility model, thus playing a crucial role in advancing the understanding and application of option pricing in complex market regimes.</div><div>The well-posedness of rough RBSDEs is established using a variant of the Doss-Sussmann transformation. Moreover, we show that rough RBSDEs can be approximated by a sequence of penalized BSDEs with rough drivers. For applications, we first develop the viscosity solution theory for rough PDEs with obstacles via rough RBSDEs. Second, we solve the corresponding optimal stopping problem and establish its connection with an American option pricing problem in the rough path setting.</div></div>","PeriodicalId":51160,"journal":{"name":"Stochastic Processes and their Applications","volume":"195 ","pages":"Article 104874"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}