Flagfolds: an approach to multi-dimensional varifolds

Fuente: arXiv
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Auteurs principaux: Buet, Blanche, Pennec, Xavier
Format: Preprint
Publié: 2023
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author Buet, Blanche
Pennec, Xavier
author_facet Buet, Blanche
Pennec, Xavier
contents By interpreting the product of the Principal Component Analysis, that is the covariance matrix, as a sequence of nested subspaces naturally coming with weights according to the level of approximation they provide, we are able to embed all $d$--dimensional Grassmannians into a stratified space of covariance matrices. We observe that Grassmannians constitute the lowest dimensional skeleton of the stratification while it is possible to define a Riemaniann metric on the highest dimensional and dense stratum, such a metric being compatible with the global stratification. With such a Riemaniann metric at hand, it is possible to look for geodesics between two linear subspaces of different dimensions that do not go through higher dimensional linear subspaces as would euclidean geodesics. Building upon the proposed embedding of Grassmannians into the stratified space of covariance matrices, we generalize the concept of varifolds to what we call flagfolds in order to model multi-dimensional shapes.
format Preprint
id arxiv_https___arxiv_org_abs_2305_10583
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Flagfolds: an approach to multi-dimensional varifolds
Buet, Blanche
Pennec, Xavier
Classical Analysis and ODEs
Differential Geometry
Statistics Theory
Primary: 49Q15. Secondary: 15B48, 53A07, 53B20, 53C22
By interpreting the product of the Principal Component Analysis, that is the covariance matrix, as a sequence of nested subspaces naturally coming with weights according to the level of approximation they provide, we are able to embed all $d$--dimensional Grassmannians into a stratified space of covariance matrices. We observe that Grassmannians constitute the lowest dimensional skeleton of the stratification while it is possible to define a Riemaniann metric on the highest dimensional and dense stratum, such a metric being compatible with the global stratification. With such a Riemaniann metric at hand, it is possible to look for geodesics between two linear subspaces of different dimensions that do not go through higher dimensional linear subspaces as would euclidean geodesics. Building upon the proposed embedding of Grassmannians into the stratified space of covariance matrices, we generalize the concept of varifolds to what we call flagfolds in order to model multi-dimensional shapes.
title Flagfolds: an approach to multi-dimensional varifolds
topic Classical Analysis and ODEs
Differential Geometry
Statistics Theory
Primary: 49Q15. Secondary: 15B48, 53A07, 53B20, 53C22
url https://arxiv.org/abs/2305.10583