Nonlocal degenerate parabolic hyperbolic equations on bounded domains

Abstract

We study well-posedness of degenerate mixed-type parabolic-hyperbolic equations $${\partial }_{t}u+\text{div}(f(u))=\mathcal{L}[b(u)]$$ on bounded domains with general Dirichlet boundary/exterior conditions. The nonlocal diffusion operator $\mathcal{L}$ can be any symmetric L{é}vy operator (e.g. fractional Laplacians) and $b$ is nondecreasing and allowed to have degenerate regions ($b^{\prime }=0$). We propose an entropy solution formulation for the problem and show uniqueness of bounded entropy solutions under general assumptions. Existence of solutions is shown in a separate paper. The uniqueness proof is based on the Kružkov doubling of variables technique and incorporates several a priori results derived from our entropy formulation: an $L^{\infty }$-bound, an energy estimate, strong initial trace, weak boundary traces, and a \textit{nonlocal} boundary condition. Our work can be seen as both extending nonlocal theories from the whole space to domains and local theories on domains to the nonlocal case. Unlike local theories our formulation does not assume energy estimates. They are now a consequence of the formulation, but as opposed to previous nonlocal theories, they play an essential role in our arguments.

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• Nonlocal diffusion and applications
• Second-Order Elliptic Integro-Differential Equations: Viscosity Solutions' Theory Revisited
• Entropy Solution Theory for Fractional Degenerate Convection-Diffusion Equations
• Continuous dependence estimates for nonlinear fractional convection-diffusion equations
• Asymptotic behaviour of solutions to fractional diffusion-convection equations
• Dirichlet Problem for Degenerate Fractional Parabolic Hyperbolic Equations