A Geometric Condition for Uniqueness of Fréchet Means of Persistence Diagrams

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Hauptverfasser: Cao, Yueqi, Monod, Anthea
Format: Preprint
Veröffentlicht: 2022
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author Cao, Yueqi
Monod, Anthea
author_facet Cao, Yueqi
Monod, Anthea
contents The Fréchet mean is an important statistical summary and measure of centrality of data; it has been defined and studied for persistent homology captured by persistence diagrams. However, the complicated geometry of the space of persistence diagrams implies that the Fréchet mean for a given set of persistence diagrams is not necessarily unique, which prohibits theoretical guarantees for empirical means with respect to population means. In this paper, we derive a variance expression for a set of persistence diagrams exhibiting a multi-matching between the persistence points known as a grouping. Moreover, we propose a condition for groupings, which we refer to as flatness; we prove that sets of persistence diagrams that exhibit flat groupings give rise to unique Fréchet means. We derive a finite sample convergence result for general groupings, which results in convergence for Fréchet means if the groupings are flat. We then interpret flat groupings in a recently-proposed general framework of Fréchet means in Alexandrov geometry. Finally, we show that for manifold-valued data, the persistence diagrams can be truncated to construct flat groupings.
format Preprint
id arxiv_https___arxiv_org_abs_2207_03943
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A Geometric Condition for Uniqueness of Fréchet Means of Persistence Diagrams
Cao, Yueqi
Monod, Anthea
Metric Geometry
Methodology
The Fréchet mean is an important statistical summary and measure of centrality of data; it has been defined and studied for persistent homology captured by persistence diagrams. However, the complicated geometry of the space of persistence diagrams implies that the Fréchet mean for a given set of persistence diagrams is not necessarily unique, which prohibits theoretical guarantees for empirical means with respect to population means. In this paper, we derive a variance expression for a set of persistence diagrams exhibiting a multi-matching between the persistence points known as a grouping. Moreover, we propose a condition for groupings, which we refer to as flatness; we prove that sets of persistence diagrams that exhibit flat groupings give rise to unique Fréchet means. We derive a finite sample convergence result for general groupings, which results in convergence for Fréchet means if the groupings are flat. We then interpret flat groupings in a recently-proposed general framework of Fréchet means in Alexandrov geometry. Finally, we show that for manifold-valued data, the persistence diagrams can be truncated to construct flat groupings.
title A Geometric Condition for Uniqueness of Fréchet Means of Persistence Diagrams
topic Metric Geometry
Methodology
url https://arxiv.org/abs/2207.03943