A Weakly Nonlinear Theory for Pattern Formation in Structured Models with Localized Solutions

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ridgway, Wesley J. M., Dalwadi, Mohit P., Pearce, Philip, Chapman, S. Jonathan
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917037705527296
author Ridgway, Wesley J. M.
Dalwadi, Mohit P.
Pearce, Philip
Chapman, S. Jonathan
author_facet Ridgway, Wesley J. M.
Dalwadi, Mohit P.
Pearce, Philip
Chapman, S. Jonathan
contents Structured models, such as PDEs structured by age or phenotype, provide a setting to study pattern formation in heterogeneous populations. Classical tools to quantify the emergence of patterns, such as linear and weakly nonlinear analyses, pose significant mathematical challenges for these models due to sharply peaked or singular steady states. Here, we present a weakly nonlinear framework that extends classical tools to structured PDE models in settings where the base state is spatially uniform, but exponentially localized in the structured variable. Our approach utilizes WKBJ asymptotics and an analysis of the Stokes phenomenon to systematically resolve the solution structure in the limit where the steady state tends to a Dirac-delta function. To demonstrate our method, we consider a chemically structured (nonlocal) model of motile bacteria that interact through quorum sensing. For this example, our analysis yields an amplitude equation that governs the solution dynamics near a linear instability, and predicts a pitchfork bifurcation. From the amplitude equation, we deduce an effective parameter grouping whose sign determines whether the pitchfork bifurcation is subcritical or supercritical. Although we demonstrate our framework for a specific example, our techniques are broadly applicable.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20781
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Weakly Nonlinear Theory for Pattern Formation in Structured Models with Localized Solutions
Ridgway, Wesley J. M.
Dalwadi, Mohit P.
Pearce, Philip
Chapman, S. Jonathan
Analysis of PDEs
Pattern Formation and Solitons
35B36 (Primary), 35B25, 35B32, 35C20, 34E20, 34M40 (Secondary)
Structured models, such as PDEs structured by age or phenotype, provide a setting to study pattern formation in heterogeneous populations. Classical tools to quantify the emergence of patterns, such as linear and weakly nonlinear analyses, pose significant mathematical challenges for these models due to sharply peaked or singular steady states. Here, we present a weakly nonlinear framework that extends classical tools to structured PDE models in settings where the base state is spatially uniform, but exponentially localized in the structured variable. Our approach utilizes WKBJ asymptotics and an analysis of the Stokes phenomenon to systematically resolve the solution structure in the limit where the steady state tends to a Dirac-delta function. To demonstrate our method, we consider a chemically structured (nonlocal) model of motile bacteria that interact through quorum sensing. For this example, our analysis yields an amplitude equation that governs the solution dynamics near a linear instability, and predicts a pitchfork bifurcation. From the amplitude equation, we deduce an effective parameter grouping whose sign determines whether the pitchfork bifurcation is subcritical or supercritical. Although we demonstrate our framework for a specific example, our techniques are broadly applicable.
title A Weakly Nonlinear Theory for Pattern Formation in Structured Models with Localized Solutions
topic Analysis of PDEs
Pattern Formation and Solitons
35B36 (Primary), 35B25, 35B32, 35C20, 34E20, 34M40 (Secondary)
url https://arxiv.org/abs/2510.20781