Optimal Brownian Stopping between radially symmetric marginals in general dimensions

Given an initial (resp., terminal) probability measure μ (resp., ν) on Rd, we characterize those optimal stopping times τ that maximize or minimize the functional E|B0−Bτ|α, α>0, where (Bt)t is Brownian motion with initial law B0∼μ and with final distribution --once stopped at τ-- equal to Bτ...

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Main Authors: Ghoussoub, N, Kim, Y, Lim, T
Format: Journal article
Published: Cornell University Library 2017
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author Ghoussoub, N
Kim, Y
Lim, T
author_facet Ghoussoub, N
Kim, Y
Lim, T
author_sort Ghoussoub, N
collection OXFORD
description Given an initial (resp., terminal) probability measure μ (resp., ν) on Rd, we characterize those optimal stopping times τ that maximize or minimize the functional E|B0−Bτ|α, α>0, where (Bt)t is Brownian motion with initial law B0∼μ and with final distribution --once stopped at τ-- equal to Bτ∼ν. The existence of such stopping times is guaranteed by Skorohod-type embeddings of probability measures in "subharmoic order" into Brownian motion. This problem is equivalent to an optimal mass transport problem with certain constraints, namely the optimal subharmonic martingale transport. Under the assumption of radial symmetry on μ and ν, we show that the optimal stopping time is a hitting time of a suitable barrier, hence is non-randomized and is unique.
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spelling oxford-uuid:8950a7de-79af-43a0-bf83-19ba25b1f1d22022-03-26T22:23:40ZOptimal Brownian Stopping between radially symmetric marginals in general dimensionsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8950a7de-79af-43a0-bf83-19ba25b1f1d2Symplectic Elements at OxfordCornell University Library2017Ghoussoub, NKim, YLim, TGiven an initial (resp., terminal) probability measure μ (resp., ν) on Rd, we characterize those optimal stopping times τ that maximize or minimize the functional E|B0−Bτ|α, α>0, where (Bt)t is Brownian motion with initial law B0∼μ and with final distribution --once stopped at τ-- equal to Bτ∼ν. The existence of such stopping times is guaranteed by Skorohod-type embeddings of probability measures in "subharmoic order" into Brownian motion. This problem is equivalent to an optimal mass transport problem with certain constraints, namely the optimal subharmonic martingale transport. Under the assumption of radial symmetry on μ and ν, we show that the optimal stopping time is a hitting time of a suitable barrier, hence is non-randomized and is unique.
spellingShingle Ghoussoub, N
Kim, Y
Lim, T
Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title_full Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title_fullStr Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title_full_unstemmed Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title_short Optimal Brownian Stopping between radially symmetric marginals in general dimensions
title_sort optimal brownian stopping between radially symmetric marginals in general dimensions
work_keys_str_mv AT ghoussoubn optimalbrownianstoppingbetweenradiallysymmetricmarginalsingeneraldimensions
AT kimy optimalbrownianstoppingbetweenradiallysymmetricmarginalsingeneraldimensions
AT limt optimalbrownianstoppingbetweenradiallysymmetricmarginalsingeneraldimensions