An inverse problem for fractional random walks on finite graphs

Fuente: arXiv
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Hauptverfasser: Covi, Giovanni, Lassas, Matti
Format: Preprint
Veröffentlicht: 2024
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author Covi, Giovanni
Lassas, Matti
author_facet Covi, Giovanni
Lassas, Matti
contents We study an inverse problem on a finite connected graph G = (X, E), on whose vertices a conductivity γ is defined. Our data consists in a sequence of partial observations of a fractional random walk on G. The observations are partial in the sense that they are limited to a fixed, observable subset B of X, while the random walk is fractional in the sense that it allows long jumps with a probability P decreasing as a fractional power of the distance along the graph. The transition probability P also depends on γ. We show that this kind of random walk data allows for the determination of a gauge class to which the transition probability matrix P belongs, which we discuss. Moreover, we show that if the transition probability matrix P is itself known, then the amount of vertices |X|, the edge set E and the conductivity γ (up to a positive factor) can be recovered. We also show a characterization of the random walk data in terms of the corresponding transition matrices P , which highlights a new surprising nonlocal property. This work is motivated by the recent strong interest in the study of the fractional Calderón problem in the Riemannian setting.
format Preprint
id arxiv_https___arxiv_org_abs_2408_05072
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An inverse problem for fractional random walks on finite graphs
Covi, Giovanni
Lassas, Matti
Analysis of PDEs
Probability
35R30, 26A33, 42B37, 46F12
We study an inverse problem on a finite connected graph G = (X, E), on whose vertices a conductivity γ is defined. Our data consists in a sequence of partial observations of a fractional random walk on G. The observations are partial in the sense that they are limited to a fixed, observable subset B of X, while the random walk is fractional in the sense that it allows long jumps with a probability P decreasing as a fractional power of the distance along the graph. The transition probability P also depends on γ. We show that this kind of random walk data allows for the determination of a gauge class to which the transition probability matrix P belongs, which we discuss. Moreover, we show that if the transition probability matrix P is itself known, then the amount of vertices |X|, the edge set E and the conductivity γ (up to a positive factor) can be recovered. We also show a characterization of the random walk data in terms of the corresponding transition matrices P , which highlights a new surprising nonlocal property. This work is motivated by the recent strong interest in the study of the fractional Calderón problem in the Riemannian setting.
title An inverse problem for fractional random walks on finite graphs
topic Analysis of PDEs
Probability
35R30, 26A33, 42B37, 46F12
url https://arxiv.org/abs/2408.05072