Optimal stopping and free boundary characterizations for some Brownian control problems

dc.creatorBudhiraja, Amarjit
dc.creatorRoss, Kevin
dc.date2009-01-16
dc.date.accessioned2026-07-07T12:31:04Z
dc.date.available2026-07-07T12:31:04Z
dc.descriptionA singular stochastic control problem with state constraints in two-dimensions is studied. We show that the value function is $C^1$ and its directional derivatives are the value functions of certain optimal stopping problems. Guided by the optimal stopping problem, we then introduce the associated no-action region and the free boundary and show that, under appropriate conditions, an optimally controlled process is a Brownian motion in the no-action region with reflection at the free boundary. This proves a conjecture of Martins, Shreve and Soner [SIAM J. Control Optim. 34 (1996) 2133--2171] on the form of an optimal control for this class of singular control problems. An important issue in our analysis is that the running cost is Lipschitz but not $C^1$. This lack of smoothness is one of the key obstacles in establishing regularity of the free boundary and of the value function. We show that the free boundary is Lipschitz and that the value function is $C^2$ in the interior of the no-action region. We then use a verification argument applied to a suitable $C^2$ approximation of the value function to establish optimality of the conjectured control.
dc.descriptionPublished in at http://dx.doi.org/10.1214/08-AAP525 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)
dc.identifierhttps://arxiv.org/abs/0901.2474
dc.identifierhttp://arxiv.org/abs/0901.2474
dc.identifierAnnals of Applied Probability 2008, Vol. 18, No. 6, 2367-2391
dc.identifierdoi:10.1214/08-AAP525
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/216331
dc.subjectProbability
dc.subject93E20, 60K25, 60G40, 49J30, 49L25, 35J60 (Primary)
dc.titleOptimal stopping and free boundary characterizations for some Brownian control problems
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