Causal functional calculus
We construct a new topology on the space of stopped paths and introduce a calculus for causal functionals on generic domains of this space. We propose a generic approach to pathwise integration without any assumption on the variation index of a path and obtain functional change of variable formulae...
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Format: | Journal article |
Language: | English |
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London Mathematical Society
2022
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author | Henry Chiu Rama Cont |
author_facet | Henry Chiu Rama Cont |
author_sort | Henry Chiu |
collection | OXFORD |
description | We construct a new topology on the space of stopped paths and introduce a calculus for causal functionals on generic domains of this space. We propose a generic approach to pathwise integration without any assumption on the variation index of a path and obtain functional change of variable formulae which extend the results of Föllmer [Séminaire de probabilités 15 (1981), 143–150] and Cont and Fournié [J. Funct. Anal. 259 (2010), no. 4, 1043–1072] to a larger class of functionals, including Föllmer's pathwise integrals. We show that a class of smooth functionals possess a pathwise analogue of the martingale property. For paths that possess finite quadratic variation, our approach extends the Föllmer–Ito calculus and removes previous restriction on the time partition sequence. We introduce a foliation structure on this path space and show that harmonic functionals may be represented as pathwise integrals of closed 1-forms. |
first_indexed | 2024-03-07T08:27:17Z |
format | Journal article |
id | oxford-uuid:2d62854e-2cdc-4bf4-b823-9997436cfe45 |
institution | University of Oxford |
language | English |
last_indexed | 2024-03-07T08:27:17Z |
publishDate | 2022 |
publisher | London Mathematical Society |
record_format | dspace |
spelling | oxford-uuid:2d62854e-2cdc-4bf4-b823-9997436cfe452024-02-22T14:53:20ZCausal functional calculusJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2d62854e-2cdc-4bf4-b823-9997436cfe45EnglishSymplectic ElementsLondon Mathematical Society2022Henry ChiuRama ContWe construct a new topology on the space of stopped paths and introduce a calculus for causal functionals on generic domains of this space. We propose a generic approach to pathwise integration without any assumption on the variation index of a path and obtain functional change of variable formulae which extend the results of Föllmer [Séminaire de probabilités 15 (1981), 143–150] and Cont and Fournié [J. Funct. Anal. 259 (2010), no. 4, 1043–1072] to a larger class of functionals, including Föllmer's pathwise integrals. We show that a class of smooth functionals possess a pathwise analogue of the martingale property. For paths that possess finite quadratic variation, our approach extends the Föllmer–Ito calculus and removes previous restriction on the time partition sequence. We introduce a foliation structure on this path space and show that harmonic functionals may be represented as pathwise integrals of closed 1-forms. |
spellingShingle | Henry Chiu Rama Cont Causal functional calculus |
title | Causal functional calculus |
title_full | Causal functional calculus |
title_fullStr | Causal functional calculus |
title_full_unstemmed | Causal functional calculus |
title_short | Causal functional calculus |
title_sort | causal functional calculus |
work_keys_str_mv | AT henrychiu causalfunctionalcalculus AT ramacont causalfunctionalcalculus |