Strong $(L^2,L^{\gamma }\cap H_0^1)$-continuity in initial data of nonlinear reaction-diffusion equation in any space dimension

Abstract

In this paper, we study the continuity in initial data of a classical reaction-diffusion equation with arbitrary $p>2$ order nonlinearity and in any space dimension $N\ge 1$. It is proved that the weak solutions can be $(L^2,L^{\gamma }\cap H_0^1)$-continuous in initial data for any $\gamma \ge 2$ (independent of the physical parameters of the system), i.e., can converge in the norm of any $L^{\gamma }\cap H_0^1$ as the corresponding initial values converge in $L^2$. Applying this to the global attractor we find that, with external forcing only in $L^2$, the attractor $\mathcal{A}$ attracts bounded subsets of $L^2$ in the norm of any $L^{\gamma }\cap H_0^1$, and that every translation set $\mathcal{A}-z_0$ of $\mathcal{A}$ for any $z_0\in \mathcal{A}$ is a finite dimensional compact subset of $L^{\gamma }\cap H_0^1$. The main technique we employ is a combination of the mathematical induction and a decomposition of the nonlinearity by which the continuity result is strengthened to $(L^2,L^{\gamma }\cap H_0^1)$-continuity and, since interpolation inequalities are avoided, the restriction on space dimension is removed.