Vanishing solutions of anisotropic parabolic equations with variable nonlinearity

We study the property of finite time vanishing of solutions of the homogeneous Dirichlet problem for the anisotropic parabolic equations

     

Extinction of solutions of parabolic equations with variable anisotropic nonlinearities

We study the Dirichlet problem for a class of nonlinear parabolic equations with nonstandard anisotropic growth conditions that generalize the evolutional p(x, t)-Laplacian. We study the property of extinction of solutions in finite time. In particular, we show that the extinction may take place even in the borderline case when the equation becomes linear as t → ∞.     

Asymptotic analysis for blow-up solutions in parabolic equations involving variable exponents

In this article, we consider non-negative solutions of the homogeneous Dirichlet problems of parabolic equations with local or nonlocal nonlinearities, involving variable exponents. We firstly obtain the necessary and sufficient conditions on the existence of blow-up solutions, and also obtain some Fujita-type conditions in bounded domains. Secondly, the blow-up rates are determined, which are described completely by the maximums of the variable exponents. Thirdly, we show that the blow-up occurs only at a single point for the equations with local nonlinearities, and in the whole domain for nonlocal nonlinearities.     

Asymptotic behavior and blow-up of solutions for infinitely degenerate semilinear parabolic equations with logarithmic nonlinearity

In this paper, we study the initial-boundary value problem for infinitely degenerate semilinear parabolic equations with logarithmic nonlinearity $u_t?{△}_{X}u=u\log ?|u|$, where $X=(X_1,X_2,?,X_m)$ is an infinitely degenerate system of vector fields, and ${△}_X:={\sum }_{j=1}^m{X}_j^2$ is an infinitely degenerate elliptic operator. Using potential well method, we first prove the invariance of some sets and vacuum isolating of solutions. Then, by the Galerkin method and the logarithmic Sobolev inequality, we obtain the global existence and blow-up at +∞ of solutions with low initial energy or critical initial energy, and we also discuss the asymptotic behavior of the solutions.     

On the continuity of solutions to elliptic equations with variable order of nonlinearity

We study the p-Laplacian with variable exponent p(x) bounded away from unity and infinity. We obtain a sufficient condition on p(x) under which all solutions of the p-Laplace equation are continuous at a fixed point of a domain, and find an estimate for the modulus of continuity of solutions.     

Existence and uniqueness of solutions of degenerate parabolic equations with variable exponents of nonlinearity

We prove the existence and uniqueness of weak solutions of the Dirichlet problem for the nonlinear degenerate parabolic equation

Doubly nonlinear parabolic equations with variable exponents of nonlinearity

In generalized Lebesgue and Sobolev spaces, we consider a mixed problem for a class of parabolic equations with double nonlinearity and nondegenerate minor terms whose exponents of nonlinearity are functions of the space variables. By using the Galerkin method, we establish the conditions of existence of weak solutions of the posed problem.     

B-method approach to blow-up solutions of fourth-order semilinear parabolic equations

Numerical Algorithms - B-method is a novel method developed by Beck et al. (SIAM J. Sci. Comput. 37(5), A2998–A3029, 2015), and has been shown theoretically to be very advantageous in time...     

Existence and localization of weak solutions of nonlinear parabolic equations with variable exponent of nonlinearity

The aim of this paper is to study the existence and uniqueness of weak solutions of the initial Neumann problem for ${u_{t}={\rm div}(|\nabla u|^{p(x,t)-2}\nabla u+\vec{F}(x,t))}$ . First, the authors construct suitable function spaces to which the solution belongs and then applies Galerkin’s approximation technique to prove the existence of weak solutions with necessary uniform estimates and a compactness argument. Second, the authors obtain the properties of extinction in finite time of weak solutions under suitable conditions by proving some energy estimates and applying a comparison principle.     

Properties of non-simultaneous blow-up solutions in nonlocal parabolic equations

This paper deals with blow-up solutions in parabolic equations coupled via nonlocal nonlinearities, subject to homogeneous Dirichlet conditions. Firstly, some criteria on non-simultaneous and simultaneous blow-up are given, including four kinds of phenomena: (i) the existence of non-simultaneous blow-up; (ii) the coexistence of non-simultaneous and simultaneous blow-up; (iii) any blow-up must be simultaneous; (iv) any blow-up must be non-simultaneous. Next, total versus single point blow-up are classified completely. Moreover, blow-up rates are obtained for both non-simultaneous and simultaneous blow-up solutions.     

Monotonicity of solutions and blow-up for semilinear parabolic equations with nonlinear memory

We show the existence of monotone in time solutions for a semilinear parabolic equation with memory. The blow-up rate estimate of the solution is known to be a consequence of the monotonicity property.     

Monotonicity of solutions and blow-up for semilinear parabolic equations with nonlinear memory

We show the existence of monotone in time solutions for a semilinear parabolic equation with memory. The blow-up rate estimate of the solution is known to be a consequence of the monotonicity property.     

Asymptotic behavior of solutions of quasilinear parabolic equations with supercritical nonlinearity

The Cauchy problem

(P)     

On directional blow-up for quasilinear parabolic equations with fast diffusion

We discuss blow-up at space infinity of solutions to quasilinear parabolic equations of the form ut=Δ?(u)+f(u) with initial data u₀∈L^∞(RN), where ? and f are nonnegative functions satisfying ?^″?0 and . We study nonnegative blow-up solutions whose blow-up times coincide with those of solutions to the O.D.E. v^′=f(v) with initial data ‖u_0‖L^∞(RN). We prove that such a solution blows up only at space infinity and possesses blow-up directions and that they are completely characterized by behavior of initial data. Moreover, necessary and sufficient conditions on initial data for blow-up at minimal blow-up time are also investigated.