Uniform contractivity of the Fisher infinitesimal model with strongly convex selection

Fuente: arXiv
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Auteurs principaux: Calvez, Vincent, Poyato, David, Santambrogio, Filippo
Format: Preprint
Publié: 2023
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author Calvez, Vincent
Poyato, David
Santambrogio, Filippo
author_facet Calvez, Vincent
Poyato, David
Santambrogio, Filippo
contents The Fisher infinitesimal model is a classical model of phenotypic trait inheritance in quantitative genetics. Here, we prove that it encompasses a remarkable convexity structure which is compatible with a selection function having a convex shape. It yields uniform contractivity along the flow, as measured by a $L^\infty$ version of the Fisher information. It induces in turn asynchronous exponential growth of solutions, associated with a well-defined, log-concave, equilibrium distribution. Although the equation is non-linear and non-conservative, our result shares some similarities with the Bakry-Emery approach to the exponential convergence of solutions to the Fokker-Planck equation with a convex potential. Indeed, the contraction takes place at the level of the Fisher information. Moreover, the key lemma for proving contraction involves the Wasserstein distance $W_\infty$ between two probability distributions of a (dual) backward-in-time process, and it is inspired by a maximum principle by Caffarelli for the Monge-Ampère equation.
format Preprint
id arxiv_https___arxiv_org_abs_2302_12063
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Uniform contractivity of the Fisher infinitesimal model with strongly convex selection
Calvez, Vincent
Poyato, David
Santambrogio, Filippo
Probability
Analysis of PDEs
35B40, 35P30, 35Q92, 47G20, 92D15
The Fisher infinitesimal model is a classical model of phenotypic trait inheritance in quantitative genetics. Here, we prove that it encompasses a remarkable convexity structure which is compatible with a selection function having a convex shape. It yields uniform contractivity along the flow, as measured by a $L^\infty$ version of the Fisher information. It induces in turn asynchronous exponential growth of solutions, associated with a well-defined, log-concave, equilibrium distribution. Although the equation is non-linear and non-conservative, our result shares some similarities with the Bakry-Emery approach to the exponential convergence of solutions to the Fokker-Planck equation with a convex potential. Indeed, the contraction takes place at the level of the Fisher information. Moreover, the key lemma for proving contraction involves the Wasserstein distance $W_\infty$ between two probability distributions of a (dual) backward-in-time process, and it is inspired by a maximum principle by Caffarelli for the Monge-Ampère equation.
title Uniform contractivity of the Fisher infinitesimal model with strongly convex selection
topic Probability
Analysis of PDEs
35B40, 35P30, 35Q92, 47G20, 92D15
url https://arxiv.org/abs/2302.12063