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1.
The asymptotic behavior of solutions of the three-dimensional nonautonomous Brinkman-Forchheimer equation is investigated. And the existence of pullback global attractors in L2 (Ω) and H01(Ω) is proved, respectively. 相似文献
2.
结合Plinio等人([Plinio D,Duane G S,Temarn R,Time-dependent attractor for the oscillon equation,Discrete Contin Dyn Syst,2011,29(1):141-167.])提出的时间依赖全局吸引子概念,运用压缩函数的方法,证明了带有时间依赖系数的非自治Plate方程时间依赖拉回吸引子在空间H~4(Ω)∩H~2_0(Ω)×H~2_0(Ω)中的存在性. 相似文献
3.
Global dynamics of nonautonomous diffusive Hindmarsh–Rose equations on a three-dimensional bounded domain in neurodynamics is investigated. The existence of a pullback attractor is proved through uniform estimates showing the pullback dissipative property and the pullback asymptotical compactness. Then the existence of pullback exponential attractor is also established by proving the smoothing Lipschitz continuity in a long run of the solution process. 相似文献
4.
The existence of pullback exponential attractors for nonautonomous dynamical system and applications to nonautonomous reaction diffusion equations
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First we establish some sufficient conditions for the existence of pullback exponential attractors by using $\omega-$limit compactness in the framework of process. Then we provide a new method to prove the existence of pullback exponential attractors. As a simple application, we prove the existence of pullback exponential attractors for nonautonomous reaction diffusion equations in $H_0^1$. 相似文献
5.
Radoslaw Czaja Messoud Efendiev 《Journal of Mathematical Analysis and Applications》2011,381(2):748-780
A family of compact and positively invariant sets with uniformly bounded fractal dimension which at a uniform exponential rate pullback attract bounded subsets of the phase space under the process is constructed. The existence of such a family, called a pullback exponential attractor, is proved for a nonautonomous semilinear abstract parabolic Cauchy problem. Specific examples will be presented in the forthcoming Part II of this work. 相似文献
6.
Assume that we want to recover $f : \Omega \to {\bf C}$ in the
$L_r$-quasi-norm ($0 < r \le \infty$) by a linear sampling method
$$
S_n f = \sum_{j=1}^n f(x^j) h_j ,
$$
where $h_j \in L_r(\Omega )$ and $x^j \in \Omega$
and $\Omega \subset {\bf R}^d$ is an arbitrary bounded Lipschitz domain.
We assume that $f$ is from the unit ball of
a Besov space $B^s_{pq} (\Omega)$ or of a
Triebel--Lizorkin space $F^s_{pq} (\Omega)$ with
parameters such that the space is compactly embedded
into $C(\overline{\Omega})$. We prove that the optimal rate
of convergence of linear sampling methods is
$$
n^{ -{s}/{d} + ({1}/{p}-{1}/{r})_+} ,
$$
nonlinear methods do not yield a better rate.
To prove this we use a result from Wendland (2001) as well
as results concerning the spaces $B^s_{pq} (\Omega) $ and $F^s_{pq}(\Omega)$.
Actually, it is another aim of this paper to complement the
existing literature about the function spaces $B^s_{pq} (\Omega)$ and $F^s_{pq}
(\Omega)$ for bounded Lipschitz domains $\Omega \subset {\bf R}^d$.
In this sense, the paper is also a continuation of a paper by Triebel (2002). 相似文献
7.
This paper deals with existence and regularity results for the problem
$ \cases{u_t-\mathrm{div}(a(x,t,u )\nabla u)=-\mathrm{div}(u\,E)
\qquad in \Omega\times (0,T),\cr u=0 \qquad on \partial \Omega\times (0,T), \cr u (0)= u_0
\qquad in \Omega ,\cr} $
under various assumptions on E and
$ u_0 $. The main difculty in studying this problem is due to the presence of the
term div(uE), which makes the differential operator non coercive
on the "energy space" $ L^2 (0, T; H_0^1 (\Omega)) $.AMS Subject Classification: 35K10, 35K15, 35K65. 相似文献
8.
O.V. Kapustyan 《Journal of Mathematical Analysis and Applications》2011,373(2):535-547
In this paper we construct a dynamical process (in general, multivalued) generated by the set of solutions of an optimal control problem for the three-dimensional Navier-Stokes system. We prove the existence of a pullback attractor for such multivalued process. Also, we establish the existence of a uniform global attractor containing the pullback attractor. Moreover, under the unproved assumption that strong globally defined solutions of the three-dimensional Navier-Stokes system exist, which guaranties the existence of a global attractor for the corresponding multivalued semiflow, we show that the pullback attractor of the process coincides with the global attractor of the semiflow. 相似文献
9.
Radoslaw Czaja Messoud Efendiev 《Journal of Mathematical Analysis and Applications》2011,381(2):766-765
The existence of a pullback exponential attractor being a family of compact and positively invariant sets with a uniform bound on their fractal dimension which at a uniform exponential rate pullback attract bounded subsets of the phase space under the evolution process is proved for the nonautonomous logistic equation and a system of reaction-diffusion equations with time-dependent external forces including the case of the FitzHugh-Nagumo system. 相似文献
10.
Regularity of pullback attractors and random equilibrium for non-autonomous stochastic FitzHugh-Nagumo system on unbounded domains
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This paper is concerned with the stochastic Fitzhugh-Nagumo system with non-autonomous terms as well as Wiener type multiplicative noises. By using the so-called notions of uniform absorption and uniformly pullback asymptotic compactness, the existences and upper semi-continuity of pullback attractors are proved for the generated random cocycle in $L^l(\mathbb{R}^N)\times L^2(\mathbb{R}^N)$ for any $l\in(2,p]$. The asymptotic compactness of the first component of the system in $L^p(\mathbb{R}^N)$ is proved by a new asymptotic a priori estimate technique, by which the plus or minus sign of the nonlinearity at large values is not required. Moreover, the condition on the existence of the unique random fixed point is obtained, in which case the influence of physical parameters on the attractors is analysed. 相似文献
11.
当非线性项满足任意阶多项式增长且外力项仅属于H~(-1)(Ω)时,研究了带衰退记忆的经典反应扩散方程的长时间动力学行为.应用抽象函数理论、半群理论以及新的估计技巧,在空间L~2(Ω)×L_μ~2(R~+;H_0~1(Ω))上证明了全局吸引子的存在性.该结果改进和推广了Chepyzhov等人(2006)及Zhong等人(2006)的相应结果. 相似文献
12.
Kazuhiro Kurata Masataka Shibata Shigeru Sakamoto 《Applied Mathematics and Optimization》2004,50(3):259-278
Let $\Omega$ be a bounded domain in ${\bf R^n}$ with Lipschitz
boundary,
$\lambda >0,$ and $1\le p \le (n+2)/(n-2)$ if $n\ge 3$ and $1\le p< +\infty$
if $n=1,2$. Let $D$ be a measurable subset of $\Omega$ which belongs
to the class
$
{\cal C}_{\beta}=\{D\subset \Omega \quad | \quad |D|=\beta\}
$
for the prescribed $\beta\in (0, |\Omega|).$
For any $D\in{\cal C}_{\beta}$, it is well known that
there exists a unique
global minimizer $u\in H^1_0(\Omega)$, which we denote by
$u_D$, of the functional
\[\quad
J_{\Omega,D}(v)=\frac12\int_{\Omega}|\nabla v|^2\,
dx+\frac{\lambda}{p+1}\int_{\Omega}|v|^{p+1}\, dx
-\int_{\Omega}\chi_Dv\,dx
\]
on $H^1_0(\Omega)$.
We consider the optimization problem
$
E_{\beta,\Omega}=\inf_{D\in {\cal C}_{\beta}} J_D(u_D)
$
and say that
a subset $D^*\in {\cal C}_{\beta}$ which attains
$E_{\beta,\Omega}$
is an optimal configuration to this problem.
In this paper we show the existence, uniqueness
and non-uniqueness, and
symmetry-preserving and symmetry-breaking phenomena of the
optimal configuration $D^*$ to this
optimization problem in various settings. 相似文献
13.
该文首先介绍拉回渐近紧非自治动力系统的概念, 给出非自治动力系统拉回吸引子存在定理. 最后证明了无界区域上具线性阻尼的二维Navier-Stokes 方程的拉回吸引子的存在性, 并给出了其Fractal维数估计. 相似文献
14.
Y. H. Hao 《数学年刊B辑(英文版)》2016,37(3):357-366
In this paper, the author considers a class of bounded pseudoconvex domains,i.e., the generalized Cartan-Hartogs domains Ω(μ, m). The first result is that the natural Khler metric g~(Ω(μ,m)) of Ω(μ, m) is extremal if and only if its scalar curvature is a constant. The second result is that the Bergman metric, the Ka¨hler-Einstein metric, the Carathéodary metric, and the Koboyashi metric are equivalent for Ω(μ, m). 相似文献
15.
Pullback attractors for modified swift-hohenberg equation on unbounded domains with non-autonomous deterministic and stochastic forcing terms
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In this paper, the existence and uniqueness of pullback attractors for the modified Swift-Hohenberg equation defined on $R^{n}$ driven by both deterministic non-autonomous forcing and additive white noise are established. We first define a continuous cocycle for the equation in $L^{2}(R^{n})$, and we prove the existence of pullback absorbing sets and the pullback asymptotic compactness of solutions when the equation with exponential growth of the external force. The long time behaviors are discussed to explain the corresponding physical phenomenon. 相似文献
16.
Xin-minXiang 《计算数学(英文版)》2004,22(1):89-100
Klein-Gordon-Schroedinger (KGS) equations are very important in physics. Some papers studied their well-posedness and numerical solution [1-4], and another works investigated the existence of global attractor in R^n and Ω包含于R^n (n≤3) [5-6,11-12]. In this paper, we discuss the dynamical behavior when we apply spectral method to find numerical approximation for periodic initial value problem of KGS equations. It includes the existence of approximate attractor AN, the upper semi-continuity on A which is a global attractor of initial problem and the upper bounds of Hausdorff and fractal dimensions for A and AN,etc. 相似文献
17.
Xiaomeng Li 《偏微分方程(英文版)》2020,33(2):171-192
Let $\Omega\subset \mathbb{R}^4$ be a smooth bounded domain, $W_0^{2,2}(\Omega)$ be the usual Sobolev space. For any positive integer $\ell$, $\lambda_{\ell}(\Omega)$ is the $\ell$-th eigenvalue of the bi-Laplacian operator. Define $E_{\ell}=E_{\lambda_1(\Omega)}\oplus E_{\lambda_2(\Omega)}\oplus\cdots\oplus E_{\lambda_{\ell}(\Omega)}$, where $E_{\lambda_i(\Omega)}$ is eigenfunction space associated with $\lambda_i(\Omega)$. $E^{\bot}_{\ell}$ denotes the orthogonal complement of $E_\ell$ in $W_0^{2,2}(\Omega)$. For $0\leq\alpha<\lambda_{\ell+1}(\Omega)$, we define a norm by $\|u\|_{2,\alpha}^{2}=\|\Delta u\|^2_2-\alpha \|u\|^2_2$ for $u\in E^\bot_{\ell}$. In this paper, using the blow-up analysis, we prove the following Adams inequalities$$\sup_{u\in E_{\ell}^{\bot},\,\| u\|_{2,\alpha}\leq 1}\int_{\Omega}e^{32\pi^2u^2}{\rm d}x<+\infty;$$moreover, the above supremum can be attained by a function $u_0\in E_{\ell}^{\bot}\cap C^4(\overline{\Omega})$ with $\|u_0\|_{2,\alpha}=1$. This result extends that of Yang (J. Differential Equations, 2015), and complements that of Lu and Yang (Adv. Math. 2009) and Nguyen (arXiv: 1701.08249, 2017). 相似文献
18.
Let (CΩ△) be a left triangulated category with a fully faithful endofunctor.We show a triangle-equivalence (S(C),△) ~=(S(C),△),where (S(C)△,) denotes the stabilization of the idempotent completion of (C,△) and (S(C),△) denotes the idempotent completion of the stabilization of (C,△). 相似文献
19.
LetΩRn be a bounded domain with a smooth boundary.We consider the longtime dynamics of a class of damped wave equations with a nonlinear memory term utt+αut-△u-∫0t 0μ(t-s)|u(s)| βu(s)ds + g(u)=f.Based on a time-uniform priori estimate method,the existence of the compact global attractor is proved for this model in the phase space H10(Ω)×L2(Ω). 相似文献
20.
In this paper,we are interested in the existence of positive solutions for the Kirchhoff type problems{-(a_1 + b_1M_1(∫_?|▽u|~pdx))△_(_pu) = λf(u,v),in ?,-(a_2 + b_2M_2(∫?|▽v|~qdx))△_(_qv) = λg(u,v),in ?,u = v = 0,on ??,where 1 p,q N,M i:R_0~+→ R~+(i = 1,2) are continuous and increasing functions.λ is a parameter,f,g ∈ C~1((0,∞) ×(0,∞)) × C([0,∞) × [0,∞)) are monotone functions such that f_s,f_t,g_s,g_t ≥ 0,and f(0,0) 0,g(0,0) 0(semipositone).Our proof is based on the sub-and super-solutions techniques. 相似文献