New multivariable mean from nonlinear matrix equation associated to the harmonic mean

Fuente: arXiv
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Main Authors: Kim, Sejong, Mer, Vatsalkumar N.
Format: Preprint
Published: 2024
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author Kim, Sejong
Mer, Vatsalkumar N.
author_facet Kim, Sejong
Mer, Vatsalkumar N.
contents Various multivariable means have been defined for positive definite matrices, such as the Cartan mean, Wasserstein mean, and Rényi power mean. These multivariable means have corresponding matrix equations. In this paper, we consider the following non-linear matrix equation: $$ X = \left[ \sum_{i=1}^{n} w_{i} [ (1-t) X + t A_{i} ]^{-1} \right]^{-1}, $$ where $t \in (0,1]$. We prove that this equation has a unique solution and define a new mean, which we denote as $G_{t}(ω; \mathbb{A})$. We explore important properties of the mean $G_{t}(ω; \mathbb{A})$ including the relationship with matrix power mean, and show that the mean $G_{t}(ω; \mathbb{A})$ is monotone in the parameter $t$. Finally, we connect the mean $G_{t}(ω; \mathbb{A})$ to a barycenter for the log-determinant divergence.
format Preprint
id arxiv_https___arxiv_org_abs_2402_10526
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle New multivariable mean from nonlinear matrix equation associated to the harmonic mean
Kim, Sejong
Mer, Vatsalkumar N.
Functional Analysis
15A24, 15B48
Various multivariable means have been defined for positive definite matrices, such as the Cartan mean, Wasserstein mean, and Rényi power mean. These multivariable means have corresponding matrix equations. In this paper, we consider the following non-linear matrix equation: $$ X = \left[ \sum_{i=1}^{n} w_{i} [ (1-t) X + t A_{i} ]^{-1} \right]^{-1}, $$ where $t \in (0,1]$. We prove that this equation has a unique solution and define a new mean, which we denote as $G_{t}(ω; \mathbb{A})$. We explore important properties of the mean $G_{t}(ω; \mathbb{A})$ including the relationship with matrix power mean, and show that the mean $G_{t}(ω; \mathbb{A})$ is monotone in the parameter $t$. Finally, we connect the mean $G_{t}(ω; \mathbb{A})$ to a barycenter for the log-determinant divergence.
title New multivariable mean from nonlinear matrix equation associated to the harmonic mean
topic Functional Analysis
15A24, 15B48
url https://arxiv.org/abs/2402.10526