Global Existence and Boundedness of Gray-Scott Model with Local and Nonlocal Diffusion
Md Shah Alam
TL;DR
The paper addresses global existence and uniform boundedness for a Gray–Scott reaction-diffusion system in which the activator $u$ diffuses via a nonlocal convolution operator $\Gamma$ and the inhibitor $v$ diffuses by the local Laplacian. The authors employ semigroup theory and duality arguments to establish a maximal, then global, solution that remains nonnegative and uniformly bounded in the sup norm for all time, leveraging quasi-positivity and a bootstrapping scheme from $L^1$ to higher $L^p$ spaces. A key contribution is extending global existence results to a mixed diffusion setting in any spatial dimension $n\ge1$, clarifying the well-posedness of the nonlocal–local diffusion combination, and providing computational demonstrations of pattern formation under this framework. The work offers a rigorous mathematical foundation for studying pattern formation under nonlocal transport, with potential implications for chemical, biological, and material systems where anomalous diffusion plays a role.
Abstract
In this paper, we study the global existence of component-wise nonnegative solutions of the Gray-Scott model in $Ω\subset \mathbb{R}^n$, $n \ge 1$, with a mixture of both local and nonlocal diffusion operators. We use semigroup theory with duality arguments to establish the global existence and boundedness of solutions of our model.
