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A note on the Cahn-Hilliard equation in H 1 ( N ) involving critical exponent

Jan W. Cholewa, Aníbal Rodríguez-Bernal (2014)

Mathematica Bohemica

We consider the Cahn-Hilliard equation in H 1 ( N ) with two types of critically growing nonlinearities: nonlinearities satisfying a certain limit condition as | u | and logistic type nonlinearities. In both situations we prove the H 2 ( N ) -bound on the solutions and show that the individual solutions are suitably attracted by the set of equilibria. This complements the results in the literature; see J. W. Cholewa, A. Rodriguez-Bernal (2012).

Applications of approximate gradient schemes for nonlinear parabolic equations

Robert Eymard, Angela Handlovičová, Raphaèle Herbin, Karol Mikula, Olga Stašová (2015)

Applications of Mathematics

We develop gradient schemes for the approximation of the Perona-Malik equations and nonlinear tensor-diffusion equations. We prove the convergence of these methods to the weak solutions of the corresponding nonlinear PDEs. A particular gradient scheme on rectangular meshes is then studied numerically with respect to experimental order of convergence which shows its second order accuracy. We present also numerical experiments related to image filtering by time-delayed Perona-Malik and tensor diffusion...

Boundedness in a quasilinear parabolic-parabolic chemotaxis system with nonlinear logistic source

Ji Liu, Jia-Shan Zheng (2015)

Czechoslovak Mathematical Journal

We study a quasilinear parabolic-parabolic chemotaxis system with nonlinear logistic source, under homogeneous Neumann boundary conditions in a smooth bounded domain. By establishing proper a priori estimates we prove that, with both the diffusion function and the chemotaxis sensitivity function being positive, the corresponding initial boundary value problem admits a unique global classical solution which is uniformly bounded. The result of this paper is a generalization of that of Cao (2014).

Comparison of explicit and implicit difference methods for quasilinear functional differential equations

W. Czernous, Z. Kamont (2011)

Applicationes Mathematicae

We give a theorem on error estimates of approximate solutions for explicit and implicit difference functional equations with unknown functions of several variables. We apply this general result to investigate the stability of difference methods for quasilinear functional differential equations with initial boundary condition of Dirichlet type. We consider first order partial functional differential equations and parabolic functional differential problems. We compare the properties of explicit...

Compétition Réaction-Diffusion et comportement asymptotique d’un problème d’obstacle doublement non linéaire

Fahd Karami (2010)

Annales de la faculté des sciences de Toulouse Mathématiques

Le but de cet article est l’étude de la compétition Réaction-Diffusion pour un problème de type β ( w ) t - d ε div a ( x , D w ) + r ε g x , β ( w ) = f , a est un opérateur de Lerray-Lions, β est une fonction continue croissante et la réaction g est une fonction croissante qui dépend de l’espace x . On suppose que les coefficients de diffusion d ε et de Réaction r ε dépendent du paramètre ε avec d ε et/ou r ε tends vers + lorsque ε 0 . Dans le cas où, le coefficient de réaction est très rapide, nous étudions le comportement asymptotique lorsque t de la solution...

Determination of a diffusion coefficient in a quasilinear parabolic equation

Fatma Kanca (2017)

Open Mathematics

This paper investigates the inverse problem of finding the time-dependent diffusion coefficient in a quasilinear parabolic equation with the nonlocal boundary and integral overdetermination conditions. Under some natural regularity and consistency conditions on the input data the existence, uniqueness and continuously dependence upon the data of the solution are shown. Finally, some numerical experiments are presented.

Existence of renormalized solutions for parabolic equations without the sign condition and with three unbounded nonlinearities

Y. Akdim, J. Bennouna, M. Mekkour, H. Redwane (2012)

Applicationes Mathematicae

We study the problem ∂b(x,u)/∂t - div(a(x,t,u,Du)) + H(x,t,u,Du) = μ in Q = Ω×(0,T), b ( x , u ) | t = 0 = b ( x , u ) in Ω, u = 0 in ∂Ω × (0,T). The main contribution of our work is to prove the existence of a renormalized solution without the sign condition or the coercivity condition on H(x,t,u,Du). The critical growth condition on H is only with respect to Du and not with respect to u. The datum μ is assumed to be in L ¹ ( Q ) + L p ' ( 0 , T ; W - 1 , p ' ( Ω ) ) and b(x,u₀) ∈ L¹(Ω).

Existence of weak solutions to doubly degenerate diffusion equations

Aleš Matas, Jochen Merker (2012)

Applications of Mathematics

We prove existence of weak solutions to doubly degenerate diffusion equations u ˙ = Δ p u m - 1 + f ( m , p 2 ) by Faedo-Galerkin approximation for general domains and general nonlinearities. More precisely, we discuss the equation in an abstract setting, which allows to choose function spaces corresponding to bounded or unbounded domains Ω n with Dirichlet or Neumann boundary conditions. The function f can be an inhomogeneity or a nonlinearity involving terms of the form f ( u ) or div ( F ( u ) ) . In the appendix, an introduction to weak differentiability...

Existence result for nonlinear parabolic problems with L¹-data

Abderrahmane El Hachimi, Jaouad Igbida, Ahmed Jamea (2010)

Applicationes Mathematicae

We study the existence of solutions of the nonlinear parabolic problem u / t - d i v [ | D u - Θ ( u ) | p - 2 ( D u - Θ ( u ) ) ] + α ( u ) = f in ]0,T[ × Ω, ( | D u - Θ ( u ) | p - 2 ( D u - Θ ( u ) ) ) · η + γ ( u ) = g on ]0,T[ × ∂Ω, u(0,·) = u₀ in Ω, with initial data in L¹. We use a time discretization of the continuous problem by the Euler forward scheme.

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