Global Analysis of the Gray-Scott Model with Fractional-Classical Diffusion
Md Shah Alam
TL;DR
The paper addresses the Gray-Scott reaction-diffusion system under mixed diffusion, combining a fractional Laplacian for $u$ with a local Laplacian for $v$ on a bounded domain under Neumann conditions. It employs semigroup theory and duality estimates to prove global existence of component-wise nonnegative solutions and uniform-in-time $L^\infty$ bounds, with a bootstrap from $L^1$ to higher norms. The authors demonstrate that fractional diffusion qualitatively reshapes pattern formation compared to the purely local model, supported by numerical simulations across varying fractional order $s$. The work provides a rigorous analytical framework for nonlocal diffusion in reaction-diffusion systems and informs modeling of pattern formation where different species diffuse at different (local vs nonlocal) rates.
Abstract
We analyze the Gray-Scott reaction--diffusion system on $Ω\subset\mathbb{R}^n$ ($n\ge 1$) with mixed diffusion combining local and nonlocal operators. Using semigroup methods and duality estimates, we prove global existence of component-wise nonnegative solutions and establish uniform-in-time bounds. Numerical simulations illustrate pattern formation and highlight qualitative differences between the purely local and mixed-diffusion models.
