A complete characterization of the blow-up solutions to discrete $p$-Laplacian parabolic equations with $q$-reaction under the mixed boundary conditions

Abstract

In this paper, we consider discrete $p$-Laplacian parabolic equations with $q$-reaction term under the mixed boundary condition and the initial condition as follows: \begin{equation*} \begin{cases} u_{t}\left(x,t\right) = Δ_{p,ω} u\left(x,t\right) +λ\left\vert u\left(x,t\right) \right\vert^{q-1} u\left(x,t\right), &\left(x,t\right) \in S \times \left(0,\infty\right), \\ μ(z)\frac{\partial u}{\partial_{p} n}(z)+σ(z)\vert u(z)\vert^{p-2}u(z)=0, &\left(x,t\right) \in \partial S \times \left[0,\infty\right), \\ u\left(x,0\right) = u_{0}(x) \geq 0, &x \in \overline{S}. \end{cases} \end{equation*} where $p>1$, $q>0$, $\lambda >0$ and $\mu ,\sigma$ are nonnegative functions on the boundary $\partial S$ of a network $S$, with $\mu (z)+\sigma (z)>0$, $z\in \partial S$. Here, ${\Delta }_{p,\omega }$ and $\frac{\partial \varphi }{{\partial }_{p}n}$ denote the discrete $p$-Laplace operator and the $p$-normal derivative, respectively. The parameters $p>1$ and $q>0$ are completely characterized to see when the solution blows up, vanishes, or exists globally. Indeed, the blow-up rates when blow-up does occur are derived. Also, we give some numerical illustrations which explain the main results.

29 pages, 13 figures