Propagation in the Fisher-KPP equation with Mixed Operator

Fuente: arXiv
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Main Authors: Barrios, Begoña, Pichucho, Bryan, Quaas, Alexander
Format: Preprint
Published: 2025
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author Barrios, Begoña
Pichucho, Bryan
Quaas, Alexander
author_facet Barrios, Begoña
Pichucho, Bryan
Quaas, Alexander
contents Our investigation focuses on the asymptotic spreading behavior of the Fisher-KPP equation with a mixed local-nonlocal operator in the diffusion (see the work by X. Cabré and J.-M. Roquejoffre, 2013, ref.[8]) to the setting of mixed diffusion, which involves both the classical and the fractional Laplacian in order to analyze the long-time dynamics of the equation. A key step in our approach involves the construction and detailed study of the heat kernel associated with the mixed operator, which we use to develop a theory of mild solutions and establish a comparison principle in suitable weighted function spaces. This framework allows us to rigorously establish the non-existence of traveling waves and characterize the large-time spreading rate of solutions. We show that the influence of the fractional Laplacian dominates over the classical Laplacian, especially in the initial layer, where it dictates the exponential propagation rate and the thickness of the solution tails.
format Preprint
id arxiv_https___arxiv_org_abs_2508_21151
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Propagation in the Fisher-KPP equation with Mixed Operator
Barrios, Begoña
Pichucho, Bryan
Quaas, Alexander
Analysis of PDEs
Our investigation focuses on the asymptotic spreading behavior of the Fisher-KPP equation with a mixed local-nonlocal operator in the diffusion (see the work by X. Cabré and J.-M. Roquejoffre, 2013, ref.[8]) to the setting of mixed diffusion, which involves both the classical and the fractional Laplacian in order to analyze the long-time dynamics of the equation. A key step in our approach involves the construction and detailed study of the heat kernel associated with the mixed operator, which we use to develop a theory of mild solutions and establish a comparison principle in suitable weighted function spaces. This framework allows us to rigorously establish the non-existence of traveling waves and characterize the large-time spreading rate of solutions. We show that the influence of the fractional Laplacian dominates over the classical Laplacian, especially in the initial layer, where it dictates the exponential propagation rate and the thickness of the solution tails.
title Propagation in the Fisher-KPP equation with Mixed Operator
topic Analysis of PDEs
url https://arxiv.org/abs/2508.21151