dorsal/arxiv
View SchemaAn It\^o Formula via Predictable Projection for Non-Semimartingale Processes
| Authors | Ramiro Fontes |
|---|---|
| Categories | |
| ArXiv ID | 2601.10359vv1 |
| URL | https://arxiv.org/abs/2601.10359 |
| License | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
Abstract
We derive an It\^o-type change-of-variables formula for a class of adapted stochastic processes that do not necessarily admit semimartingale structure. The formulation is based on an intrinsic Hilbert-space derivative together with a predictable projection operator, allowing stochastic integrals to be expressed without reliance on quadratic variation or anticipative calculus. The resulting formula replaces the classical quadratic variation term with a computable second-order contribution expressed as a norm of the projected derivative. In the semimartingale case, the formula reduces to the classical It\^o formula. The approach applies naturally to processes with memory and non-Markovian dependence, providing a unified and intrinsic framework for stochastic calculus beyond the semimartingale setting.
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"abstract": "We derive an It\\^o-type change-of-variables formula for a class of adapted stochastic processes that do not necessarily admit semimartingale structure. The formulation is based on an intrinsic Hilbert-space derivative together with a predictable projection operator, allowing stochastic integrals to be expressed without reliance on quadratic variation or anticipative calculus.\n The resulting formula replaces the classical quadratic variation term with a computable second-order contribution expressed as a norm of the projected derivative. In the semimartingale case, the formula reduces to the classical It\\^o formula. The approach applies naturally to processes with memory and non-Markovian dependence, providing a unified and intrinsic framework for stochastic calculus beyond the semimartingale setting.",
"arxiv_id": "2601.10359",
"authors": [
"Ramiro Fontes"
],
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"math.PR"
],
"license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
"title": "An It\\^o Formula via Predictable Projection for Non-Semimartingale Processes",
"url": "https://arxiv.org/abs/2601.10359",
"version": "v1"
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