The L^p-Fisher-Rao metric and Amari-Cencov alpha-connections - Archive ouverte HAL Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2023

The L^p-Fisher-Rao metric and Amari-Cencov alpha-connections

Résumé

We introduce a family of Finsler metrics, called the $L^p$-Fisher-Rao metrics $F_p$, for $p\in (1,\infty)$, which generalizes the classical Fisher-Rao metric $F_2$, both on the space of densities $\Dens$ and probability densities $\Prob$. We then study their relations to the Amari-\u{C}encov $\alpha$-connections $\nabla^{(\alpha)}$ from information geometry: on $\Dens$, the geodesic equations of $F_p$ and $\nabla^{(\alpha)}$ coincide, for $p = 2/(1-\alpha)$. Both are pullbacks of canonical constructions on $L^p(M)$, in which geodesics are simply straight lines. In particular, this gives a new variational interpretation of $\alpha$-geodesics as being energy minimizing curves. On $\Prob$, the $F_p$ and $\nabla^{(\alpha)}$ geodesics can still be thought as pullbacks of natural operations on the unit sphere in $L^p(M)$, but in this case they no longer coincide unless $p=2$. Using this transformation, we solve the geodesic equation of the $\alpha$-connection by showing that the geodesic are pullbacks of projections of straight lines onto the unit sphere, and they always cease to exists after finite time when they leave the positive part of the sphere. This unveils the geometric structure of solutions to the generalized Proudman-Johnson equations, and generalizes them to higher dimensions. In addition, we calculate the associate tensors of $F_p$, and study their relation to $\nabla^{(\alpha)}$.
Fichier principal
Vignette du fichier
main.pdf (1.61 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04136763 , version 1 (22-06-2023)
hal-04136763 , version 2 (30-07-2023)

Identifiants

Citer

Martin Bauer, Alice Le Brigant, Yuxiu Lu, Cy Maor. The L^p-Fisher-Rao metric and Amari-Cencov alpha-connections. 2023. ⟨hal-04136763v2⟩
63 Consultations
73 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More