Uniqueness and nonlinear stability of entire solutions in a parabolic-parabolic chemotaxis models with logistic source on bounded heterogeneous environments
Tahir Bachar Issa
TL;DR
This work analyzes the full parabolic-parabolic chemotaxis system with a logistic-type nonlocal source on bounded heterogeneous domains and proves the existence, uniqueness, and global stability of a positive entire solution $(u^*,v^*)$. Under structural conditions (H1)/(H2) and a smallness/regularity assumption (H3) together with a limsup stability criterion involving the data through $L_1$ and $L_2$, any global classical solution converges to $(u^*,v^*)$ in $C^0(ar{\Omega})$ as $t\to\infty$. The authors extend the method of eventual comparison from homogeneous convex settings to nonconvex heterogeneous environments, leveraging a crucial $v$-bound in $W^{2,\infty}$ and a two-step uniqueness argument to obtain a single globally attracting positive entire solution. The results provide rigorous long-time guarantees for population-chemotaxis dynamics under spatial heterogeneity, enhancing understanding of stability in biologically relevant settings.
Abstract
This paper studies the asymptotic behavior of solutions of the parabolic-parabolic chemotaxis model with logistic-type sources in heterogeneous bounded domains: \begin{equation*} \label{u-v-eq00} \begin{cases} u_t=Δu-χ\nabla\cdot (u \nabla v)+u\Big(a_0(t,x)-a_1(t,x)u-a_2(t,x)\int_Ωu\Big),\quad x\in Ω\cr τv_t=Δv-λv +μu,\quad x\in Ω\cr \frac{\p u}{\p ν}=\frac{\p v}{\p ν}=0,\quad x\in\pΩ. \end{cases}\qquad(\ast) \end{equation*} \noindent We find parameter regions in which the system has a unique positive entire solution, which is globally asymptotically stable. {More precisely under suitable assumptions on the model's parameters, the system has a unique entire positive solution $(u^*(x,t),v^*(x,t))$ such that for any %$t_0\in\RR$ and $u_0 \in C^0(\barΩ),$ $v_0 \in W^{1,\infty}(\barΩ)$ with $u_0,v_0\ge 0$ and $u_0\not\equiv 0$, the global classical solution $(u(x,t;t_0,u_0,v_0)$, $v(x,t;t_0,u_0,v_0))$ of $(\ast)$ satisfies $$ \lim_{t \to \infty}\Big(\sup_{t_0 \in \mathbb{R}}\|u(\cdot,t;t_0,u_0,v_0)-u^*(\cdot,t)\|_{C^0(\barΩ)}+\sup_{t_0 \in \mathbb{R}}\|v(\cdot,t;t_0,u_0,v_0)-v^*(\cdot,t)\|_{C^0(\barΩ)}\Big)=0. $$