scholarly journals Flow invariance for perturbed nonlinear evolution equations

1996 ◽  
Vol 1 (4) ◽  
pp. 417-433 ◽  
Author(s):  
Dieter Bothe

LetXbe a real Banach space,J=[0,a]⊂R,A:D(A)⊂X→2X\ϕanm-accretive operator andf:J×X→Xcontinuous. In this paper we obtain necessary and sufficient conditions for weak positive invariance (also called viability) of closed setsK⊂Xfor the evolution systemu′+Au∍f(t,u)  on  J=[0,a]. More generally, we provide conditions under which this evolution system has mild solutions satisfying time-dependent constraintsu(t)∈K(t)onJ. This result is then applied to obtain global solutions of reaction-diffusion systems with nonlinear diffusion, e.g. of typeut=ΔΦ(u)+g(u)  in  (0,∞)×Ω,   Φ(u(t,⋅))|∂Ω=0,   u(0,⋅)=u0under certain assumptions on the setΩ⊂Rnthe functionΦ(u1,…,um)=(φ1(u1),…,φm(um))andg:R+m→Rm.

2010 ◽  
Vol 12 (06) ◽  
pp. 1031-1054 ◽  
Author(s):  
JESÚS GARCÍA-FALSET ◽  
SIMEON REICH

We study the existence of integral solutions to a class of nonlinear evolution equations of the form [Formula: see text] where A : D(A) ⊆ X → 2X is an m-accretive operator on a Banach space X, and f : [0, T] × X → X and [Formula: see text] are given functions. We obtain sufficient conditions for this problem to have a unique integral solution.


Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Tahira Jabeen ◽  
Ravi P. Agarwal ◽  
Vasile Lupulescu ◽  
Donal O’Regan

In this paper, we establish sufficient conditions for the existence of mild solutions for certain impulsive evolution differential equations with causal operators in separable Banach spaces. We rely on the existence of mild solutions for the strongly continuous semigroups theory, the measure of noncompactness and the Schauder fixed point theorem. We consider the impulsive integro-differential evolutions equation and impulsive reaction diffusion equations (which could include symmetric kernels) as applications to illustrate our main results.


2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Yongqin Xie ◽  
Zhufang He ◽  
Chen Xi ◽  
Zheng Jun

We prove the asymptotic regularity of global solutions for a class of semilinear evolution equations in H01(Ω)×H01(Ω). Moreover, we study the long-time behavior of the solutions. It is proved that, under the natural assumptions, these equations possess the compact attractor 𝒜 which is bounded in H2(Ω)×H2(Ω), where the nonlinear term f satisfies a critical exponential growth condition.


2019 ◽  
Vol 84 (5) ◽  
pp. 974-1000
Author(s):  
Guillaume Cantin ◽  
M A Aziz-Alaoui ◽  
Nathalie Verdière

Abstract This paper is devoted to the analysis of the asymptotic behaviour of a complex network of reaction–diffusion systems for a geographical model, which was proposed recently, in order to better understand behavioural reactions of individuals facing a catastrophic event. After stating sufficient conditions for the problem to admit a positively invariant region, we establish energy estimates and prove the existence of a family of exponential attractors. We explore the influence of the size of the network on the nature of those attractors, in correspondence with the geographical background. Numerical simulations illustrate our theoretical results and show the various possible dynamics of the problem.


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jorge A. Esquivel-Avila

We consider an abstract coupled evolution system of second order in time. For any positive value of the initial energy, in particular for high energies, we give sufficient conditions on the initial data to conclude nonexistence of global solutions. We compare our results with those in the literature and show how we improve them.


Author(s):  
CARLO MARINELLI ◽  
MICHAEL RÖCKNER

In the semigroup approach to stochastic evolution equations, the fundamental issue of uniqueness of mild solutions is often "reduced" to the much easier problem of proving uniqueness for strong solutions. This reduction is usually carried out in a formal way, without really justifying why and how one can do that. We provide sufficient conditions for uniqueness of mild solutions to a broad class of semilinear stochastic evolution equations with coefficients satisfying a monotonicity assumption.


2018 ◽  
Vol 1 (2) ◽  
pp. 9-31
Author(s):  
Attaullah

In this paper, Laplace Adomian decomposition method (LADM) is applied to solve linear and nonlinear partial differential equations (PDEs). With the help of proposed method, we handle the approximated analytical solutions to some interesting classes of PDEs including nonlinear evolution equations, Cauchy reaction-diffusion equations and the Klien-Gordon equations.


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