共查询到20条相似文献，搜索用时 15 毫秒
1.
We consider the three dimensional Cauchy problem for the Laplace equation uxx(x,y,z)+ uyy(x,y,z)+ uzz(x,y,z) = 0, x ∈ R,y ∈ R,0 z ≤ 1, u(x,y,0) = g(x,y), x ∈ R,y ∈ R, uz(x,y,0) = 0, x ∈ R,y ∈ R, where the data is given at z = 0 and a solution is sought in the region x,y ∈ R,0 z 1. The problem is ill-posed, the solution (if it exists) doesn't depend continuously on the initial data. Using Galerkin method and Meyer wavelets, we get the uniform stable wavelet approximate solution. Furthermore, we shall give a recipe for choosing the coarse level resolution. 相似文献
2.
The paper suggests some conditions on the lower order terms, which provide that the solution of the Dirichlet problem for
the general elliptic equation of the second order
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$
\begin{gathered}
- \sum\limits_{i,j = 1}^n {\left( {a_{i j} \left( x \right)u_{x_i } } \right)_{x_j } + } \sum\limits_{i = 1}^n {b_i \left( x \right)u_{x_i } - } \sum\limits_{i = 1}^n {\left( {c_i \left( x \right)u} \right)_{x_i } + d\left( x \right)u = f\left( x \right) - divF\left( x \right), x \in Q,} \hfill \\
\left. u \right|_{\partial Q} = u_0 \in L_2 \left( {\partial Q} \right) \hfill \\
\end{gathered}
$
\begin{gathered}
- \sum\limits_{i,j = 1}^n {\left( {a_{i j} \left( x \right)u_{x_i } } \right)_{x_j } + } \sum\limits_{i = 1}^n {b_i \left( x \right)u_{x_i } - } \sum\limits_{i = 1}^n {\left( {c_i \left( x \right)u} \right)_{x_i } + d\left( x \right)u = f\left( x \right) - divF\left( x \right), x \in Q,} \hfill \\
\left. u \right|_{\partial Q} = u_0 \in L_2 \left( {\partial Q} \right) \hfill \\
\end{gathered}
相似文献
3.
This paper concerns the study of the numerical approximation for the following initialboundary value problem
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$
\left\{ \begin{gathered}
u_t - u_{xx} = f\left( u \right), x \in \left( {0,1} \right), t \in \left( {0,T} \right), \hfill \\
u\left( {0,t} \right) = 0, u_x \left( {1,t} \right) = 0, t \in \left( {0,T} \right), \hfill \\
u\left( {x,0} \right) = u_0 \left( x \right), x \in \left[ {0,1} \right], \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
u_t - u_{xx} = f\left( u \right), x \in \left( {0,1} \right), t \in \left( {0,T} \right), \hfill \\
u\left( {0,t} \right) = 0, u_x \left( {1,t} \right) = 0, t \in \left( {0,T} \right), \hfill \\
u\left( {x,0} \right) = u_0 \left( x \right), x \in \left[ {0,1} \right], \hfill \\
\end{gathered} \right.
相似文献
4.
The existence of a positive solution for the generalized predator-prey model for two species
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$
\begin{gathered}
\Delta u + u(a + g(u,v)) = 0in\Omega , \hfill \\
\Delta v + v(d + h(u,v)) = 0in\Omega , \hfill \\
u = v = 0on\partial \Omega , \hfill \\
\end{gathered}
$
\begin{gathered}
\Delta u + u(a + g(u,v)) = 0in\Omega , \hfill \\
\Delta v + v(d + h(u,v)) = 0in\Omega , \hfill \\
u = v = 0on\partial \Omega , \hfill \\
\end{gathered}
相似文献
5.
In this paper we consider a class of nonlinear elliptic problems of the type
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$
\left\{ \begin{gathered}
- div(a(x,\nabla u)) - div(\Phi (x,u)) = fin\Omega \hfill \\
u = 0on\partial \Omega , \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
- div(a(x,\nabla u)) - div(\Phi (x,u)) = fin\Omega \hfill \\
u = 0on\partial \Omega , \hfill \\
\end{gathered} \right.
相似文献
6.
The purpose of this paper is to study the existence of periodic solutions for the non-autonomous second order Hamiltonian
system
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$
\left\{ \begin{gathered}
\ddot u(t) = \nabla F(t,u(t)),a.e.t \in [0,T], \hfill \\
u(0) - u(T) = \dot u(0) - \dot u(T) = 0 \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
\ddot u(t) = \nabla F(t,u(t)),a.e.t \in [0,T], \hfill \\
u(0) - u(T) = \dot u(0) - \dot u(T) = 0 \hfill \\
\end{gathered} \right.
相似文献
7.
In this paper we deal with the four-point singular boundary value problem
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$
\left\{ \begin{gathered}
(\phi _p (u'(t)))' + q(t)f(t,u(t),u'(t),u'(t)) = 0,t \in (0,1), \hfill \\
u'(0) - \alpha u(\xi ) = 0,u'(1) + \beta u(\eta ) = 0, \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
(\phi _p (u'(t)))' + q(t)f(t,u(t),u'(t),u'(t)) = 0,t \in (0,1), \hfill \\
u'(0) - \alpha u(\xi ) = 0,u'(1) + \beta u(\eta ) = 0, \hfill \\
\end{gathered} \right.
相似文献
8.
This paper deals with the periodic boundary value problem for nonlinear impulsive functional differential equation
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$
\left\{ \begin{gathered}
x'(t) = f(t,x(t),x(\alpha _1 (t)),...,x(\alpha _n (t)))fora.e.t \in [0,T], \hfill \\
\Delta x(t_k ) = I_k (x(t_k )),k = 1,...,m, \hfill \\
x(0) = x(T). \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
x'(t) = f(t,x(t),x(\alpha _1 (t)),...,x(\alpha _n (t)))fora.e.t \in [0,T], \hfill \\
\Delta x(t_k ) = I_k (x(t_k )),k = 1,...,m, \hfill \\
x(0) = x(T). \hfill \\
\end{gathered} \right.
相似文献
9.
we study an initial-boundary-value problem for the ＂good＂ Boussinesq equation on the half line {δt^2u-δx^2u＋δx^4u＋δx^2u^2=0,t〉0,x〉0. u（0,t）=h1（t）,δx^2u（0,t） =δth2（t）, u（x,0）=f（x）,δtu（x,0）=δxh（x）. The existence and uniqueness of low reguality solution to the initial-boundary-value problem is proved when the initial-boundary data （f, h, h1, h2） belong to the product space H^5（R^＋）×H^s-1（R^＋）×H^s/2＋1/4（R^＋）×H^s/2＋1/4（R^＋） 1 The analyticity of the solution mapping between the initial-boundary-data and the with 0 ≤ s 〈 1/2. solution space is also considered. 相似文献
10.
The authors study the existence of nontrivial solutions to p-Laplacian variational inclusion systems
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$\left\{ \begin{gathered}
- \Delta _p u + \left| u \right|^{p - 2} u \in \partial _1 F\left( {u,v} \right), in \mathbb{R}^N , \hfill \\
- \Delta _p v + \left| v \right|^{p - 2} v \in \partial _2 F\left( {u,v} \right), in \mathbb{R}^N , \hfill \\
\end{gathered} \right.$\left\{ \begin{gathered}
- \Delta _p u + \left| u \right|^{p - 2} u \in \partial _1 F\left( {u,v} \right), in \mathbb{R}^N , \hfill \\
- \Delta _p v + \left| v \right|^{p - 2} v \in \partial _2 F\left( {u,v} \right), in \mathbb{R}^N , \hfill \\
\end{gathered} \right. 相似文献
11.
The existence of at least one solution of the following multi-point boundary value problem
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$
\left\{ \begin{gathered}
[\varphi (x'(t))]' = f(t,x(t),x'(t)),t \in (0,1), \hfill \\
x(0) - \sum\limits_{i = 1}^m {\alpha _i x'(\xi _i ) = 0,} \hfill \\
x'(1) - \sum\limits_{i = 1}^m {\beta _i x(\xi _i ) = 0} \hfill \\
\end{gathered} \right.
$
\left\{ \begin{gathered}
[\varphi (x'(t))]' = f(t,x(t),x'(t)),t \in (0,1), \hfill \\
x(0) - \sum\limits_{i = 1}^m {\alpha _i x'(\xi _i ) = 0,} \hfill \\
x'(1) - \sum\limits_{i = 1}^m {\beta _i x(\xi _i ) = 0} \hfill \\
\end{gathered} \right.
相似文献
12.
This paper is devoted to the study of the period function for a class of reversible quadratic system
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$
\begin{gathered}
\dot x = - 2xy, \hfill \\
\dot y = k - 1 - 2kx + \left( {k + 1} \right)x^2 - \tfrac{1}
{2}y^2 . \hfill \\
\end{gathered}
$
\begin{gathered}
\dot x = - 2xy, \hfill \\
\dot y = k - 1 - 2kx + \left( {k + 1} \right)x^2 - \tfrac{1}
{2}y^2 . \hfill \\
\end{gathered}
相似文献
13.
We consider the system
|
$\begin{gathered}
x_{k + 1} = A_k x_k + b_k u_k , \hfill \\
u_{k + 1} = m_k^* x_k ,k = 1,2,..., \hfill \\
\end{gathered}
$\begin{gathered}
x_{k + 1} = A_k x_k + b_k u_k , \hfill \\
u_{k + 1} = m_k^* x_k ,k = 1,2,..., \hfill \\
\end{gathered}
相似文献
14.
The initial boundary value problem
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$ {*{20}{c}} {\rho {u_{tt}} - {{\left( {\Gamma {u_x}} \right)}_x} + A{u_x} + Bu = 0,} \hfill & {x > 0,\quad 0 < t < T,} \hfill \\ {u\left| {_{t = 0}} \right. = {u_t}\left| {_{t = 0}} \right. = 0,} \hfill & {x \geq 0,} \hfill \\ {u\left| {_{x = 0}} \right. = f,} \hfill & {0 \leq t \leq T,} \hfill \\ $ \begin{array}{*{20}{c}} {\rho {u_{tt}} - {{\left( {\Gamma {u_x}} \right)}_x} + A{u_x} + Bu = 0,} \hfill & {x > 0,\quad 0 < t < T,} \hfill \\ {u\left| {_{t = 0}} \right. = {u_t}\left| {_{t = 0}} \right. = 0,} \hfill & {x \geq 0,} \hfill \\ {u\left| {_{x = 0}} \right. = f,} \hfill & {0 \leq t \leq T,} \hfill \\ \end{array} 相似文献
15.
The solvability of the nonlocal boundary value problem in a class of functions is investigated for a quasilinear parabolic equation. The solution uniqueness follows from the maximum principle. 相似文献
16.
The authors study the existence of homoclinic type solutions for the following system of diffusion equations on R × RN:{■tu-xu + b ·▽xu + au + V(t,x)v = Hv(t,x,u,v),-■tv-xv-b·▽xv + av + V(t,x)u = Hu(t,x,u,v),where z =(u,v):R × RN → Rm × Rm,a > 0,b =(b1,···,bN) is a constant vector and V ∈ C(R × RN,R),H ∈ C1(R × RN × R2m,R).Under suitable conditions on V(t,x) and the nonlinearity for H(t,x,z),at least one non-stationary homoclinic solution with least energy is obtained. 相似文献
17.
Using the Leggett-Williams fixed point theorem,we will obtain at least three symmetric positive solutions to the second-order nonlocal boundary value problem of the form u(t)+g(t)f(t,u(t))=0,0 相似文献
18.
We study nonnegative solutions of the initial value problem for a weakly coupled system |
相似文献
19.
The authors consider the finite volume approximation of a reaction-diffusion system with fast reversible reaction.It is deduced from a priori estimates that the approximate solution converges to the weak solution of the reaction-diffusion problem and satisfies estimates which do not depend on the kinetic rate.It follows that the solution converges to the solution of a nonlinear diffusion problem,as the size of the volume elements and the time steps converge to zero while the kinetic rate tends to infinity. 相似文献
20.
It is proved that the boundary-value problem , has a solution, provided that the following conditions are fulfilled: , and, for ϕ(u) ≡ 0, the Galerkin method converges in the norm of the space H 1(a, b; a). Several theorems of a similar kind are presented. Bibliography: 4 titles.
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 334, 2006, pp. 246–266. 相似文献
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