与年龄相关的非线性种群扩散方程广义解的存在性

讨论了一类与年龄相关和空间扩散的非线性时变种群扩散方程广义解的存在性问题 .利用抛物偏微分方程的有关理论和延滞法 ,证明了方程广义解的存在性 。

与年龄相关的非线性种群扩散方程广义解的存在唯一性

讨论了一类与年龄相关的非线性时变种群扩散方程广义解的存在唯一性.利用截断函数方法,采用先验估计、紧性定理等证明了当μ在r=A附近无界时,系统(p)广义解的存在唯一性.为讨论这一系统最优控制等问题提供了严格的理论依据.

一类半线性种群扩散方程的非负解

依据抛物偏微分方程一般理论和比较原理 ,证明了一类半线性种群扩散偏微分方程第一边值问题的非负解的存在性与惟一性 .

Analytical Approach for Nonlinear Partial Differential Equations of Fractional Order

The purpose of the paper is to present analytical and numerical solutions of a degenerate parabolic equation with time-fractional derivatives arising in the spatial diffusion of biological populations. The homotopy-perturbation method is employed for solving this class of equations, and the time-fractional derivatives are described in the sense of Caputo. Comparisons are made with those derived by Adomian＇s decomposition method, revealing that the homotopy perturbation method is more accurate and convenient than the Adomian＇s decomposition method. Furthermore, the results reveal that the approximate solution continuously depends on the time-fractional derivative and the proposed method incorporating the Caputo derivatives is a powerful and efficient technique for solving the fractional differential equations without requiring linearization or restrictive assumptions. The basis ideas presented in the paper can be further applied to solve other similar fractional partial differential equations.