Projective Wishart Distributions

Fuente: arXiv
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Main Author: Chevallier, Emmanuel
Format: Preprint
Published: 2024
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author Chevallier, Emmanuel
author_facet Chevallier, Emmanuel
contents We are interested in the distribution of Wishart samples after forgetting their scaling factors. We call such a distribution a projective Wishart distribution. We show that projective Wishart distributions have strong links with the affine-invariant geometry of symmetric positive definite matrices in the real case or Hermitian positive definite matrices in the complex case. First, the Fr{é}chet mean of a projective Wishart distribution is the covariance parameter, up to a scaling factor, of the corresponding Wishart distribution. Second, in the case of 2 by 2 matrices, the densities have simple expressions in term of the affine-invariant distance.
format Preprint
id arxiv_https___arxiv_org_abs_2407_09582
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Projective Wishart Distributions
Chevallier, Emmanuel
Statistics Theory
Probability
We are interested in the distribution of Wishart samples after forgetting their scaling factors. We call such a distribution a projective Wishart distribution. We show that projective Wishart distributions have strong links with the affine-invariant geometry of symmetric positive definite matrices in the real case or Hermitian positive definite matrices in the complex case. First, the Fr{é}chet mean of a projective Wishart distribution is the covariance parameter, up to a scaling factor, of the corresponding Wishart distribution. Second, in the case of 2 by 2 matrices, the densities have simple expressions in term of the affine-invariant distance.
title Projective Wishart Distributions
topic Statistics Theory
Probability
url https://arxiv.org/abs/2407.09582