Existence and nonexistence of global solutions to fast diffusions with source

On Existence and Nonexistence Global Solutions of Reaction-Diffusion Equations

We consider the initial value problem for the reaction-diffusion equation ut = ∆u + f(u). In this paper we show the existence and nonexistence of the global solutions in time. Especially, we extend the condition of the nonlinear terms to more general. We have the results of the existence and the nonexistence for the equation with the nonlinear term f satisfying lim infs→0 f(s)/sp > 0 and lim su...

Existence and Nonexistence of Global Solutions in Time for a Reaction-Diffusion System with Inhomogeneous Terms

We consider the initial value problem for the reaction-diffusion system with inhomogeneous terms. In this paper we show the existence and nonexistence of global solution in time. Especially, for the nonexistence we extend the conditions of the nonlinear terms and the initial data to the weaker conditions. We prove that for the nonlinear term and the initial data whose support is included in som...

Global Existence and Nonexistence for Nonlinear Wave Equations with Damping and Source Terms

We consider an initial-boundary value problem for a nonlinear wave equation in one space dimension. The nonlinearity features the damping term |u|m−1 ut and a source term of the form |u|p−1 u, with m, p > 1. We show that whenever m ≥ p, then local weak solutions are global. On the other hand, we prove that whenever p > m and the initial energy is negative, then local weak solutions cannot be gl...

Existence and Nonexistence of Global Solutions of Degenerate and Singular Parabolic Systems

where p,q > 1 and u(x,0) = u0(x), v(x,0) = v0(x), x ∈ R. Systems like (1.1) and (1.2) will be called degenerate and singular, respectively. Several authors have addressed this problem recently: we refer the interested reader to the papers by Levine [4] and Deng and Levine [1] for a survey of the literature on this subject. In the proofs we follow the technique developed by Mitidieri and Pohozae...

Existence and Nonexistence of Global Solutions of a Weakly Coupled System of Reaction-Diffusion Equations