On a bi-dimensional chemo-repulsion model with nonlinear production

TL;DR

This paper analyzes a bi-dimensional chemo-repulsion model with nonlinear production, establishing existence, uniqueness, and optimal control solutions for different nonlinearities, with implications for biological and chemical systems modeling.

Contribution

It provides the first rigorous analysis of existence, uniqueness, and optimal control for a nonlinear chemo-repulsion PDE with bilinear control in 2D domains.

Findings

Proved global strong solutions for quadratic production ($p=2$).

Derived optimality system and regularity of Lagrange multipliers.

Extended analysis to sub-quadratic production ($1<p<2$).

Abstract

In this paper, we study the following parabolic chemo-repulsion with nonlinear production model: $$ \left\{ \begin{array}{rcl} \partial_tu-\Delta u&=&\nabla\cdot(u\nabla v),\\ \partial_tv-\Delta v+v&=&u^p+fv\, 1_{\Omega_c}. \end{array} \right. $$ This problem is related to a bilinear control problem, where the state $(u,v)$ is the cell density and the chemical concentration respectively, and the control $f$ acts in a bilinear form in the chemical equation. For $2D$ domains, we first consider the case of quadratic signal production ($p=2$), proving the existence and uniqueness of global strong state solution for each control, and the existence of global optimum solution. Afterwards, we deduce the optimality system for any local optimum via a Lagrange multiplier Theorem, proving regularity of the Lagrange multipliers. Finally, we consider the case of signal production $u^p$ with $1<p<2$.