2020/10/30 by Esther S. Daus, Maria Pia Gualdani, Daus, Esther S. +7
Computer Science · Mathematics · #Advanced Mathematical Modeling in Engineering #Analysis of PDEs (math.AP) #FOS: Mathematics #Fractional Differential Equations Solutions #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.2010.16332
openalex publication_date 2020/10/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper we investigate existence of solutions for the system: \ Dαtu=\textrmdiv(u ∇ p),
Dαtp=-(-Δ)sp+u2, . in \mathbbT3 for 0< s ≤ 1, and 0< α≤ 1. The term Dαt u denotes the Caputo derivative, which models memory effects in time. The fractional Laplacian (-Δ)s represents the Lévy diffusion. We prove global existence of nonnegative weak solutions that satisfy a variational inequality. The proof uses several approximations steps, including an implicit Euler time discretization. We show that the proposed discrete Caputo derivative satisfies several important properties, including positivity preserving, convexity and rigorous convergence towards the continuous Caputo derivative. Most importantly, we give a strong compactness criteria for piecewise constant functions, in the spirit of Aubin-Lions theorem, based on bounds of the discrete Caputo derivative.