A regularized Kellerer theorem in arbitrary dimension

Fuente: arXiv
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Main Authors: Pammer, Gudmund, Robinson, Benjamin A., Schachermayer, Walter
Format: Preprint
Published: 2022
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author Pammer, Gudmund
Robinson, Benjamin A.
Schachermayer, Walter
author_facet Pammer, Gudmund
Robinson, Benjamin A.
Schachermayer, Walter
contents We present a multidimensional extension of Kellerer's theorem on the existence of mimicking Markov martingales for peacocks, a term derived from the French for stochastic processes increasing in convex order. For a continuous-time peacock in arbitrary dimension, after Gaussian regularization, we show that there exists a strongly Markovian mimicking martingale Itô diffusion. A novel compactness result for martingale diffusions is a key tool in our proof. Moreover, we provide counterexamples to show, in dimension $d \geq 2$, that uniqueness may not hold, and that some regularization is necessary to guarantee existence of a mimicking Markov martingale.
format Preprint
id arxiv_https___arxiv_org_abs_2210_13847
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A regularized Kellerer theorem in arbitrary dimension
Pammer, Gudmund
Robinson, Benjamin A.
Schachermayer, Walter
Probability
60G44, 60J60, 60H10, 60J25 (Primary) 60F99 (Secondary)
We present a multidimensional extension of Kellerer's theorem on the existence of mimicking Markov martingales for peacocks, a term derived from the French for stochastic processes increasing in convex order. For a continuous-time peacock in arbitrary dimension, after Gaussian regularization, we show that there exists a strongly Markovian mimicking martingale Itô diffusion. A novel compactness result for martingale diffusions is a key tool in our proof. Moreover, we provide counterexamples to show, in dimension $d \geq 2$, that uniqueness may not hold, and that some regularization is necessary to guarantee existence of a mimicking Markov martingale.
title A regularized Kellerer theorem in arbitrary dimension
topic Probability
60G44, 60J60, 60H10, 60J25 (Primary) 60F99 (Secondary)
url https://arxiv.org/abs/2210.13847