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1.
Let be a bounded Lipschitz domain and consider the Dirichlet energy functional
over the space of measure preserving maps
In this paper we introduce a class of maps referred to as generalised twists and examine them in connection with the Euler–Lagrange equations associated with over . The main result here is that in even dimensions the latter equations admit infinitely many solutions, modulo isometries, amongst such maps. We investigate various qualitative properties of these solutions in view of a remarkably interesting previously unknown explicit formula.  相似文献   

2.
In this paper we establish an existence and regularity result for solutions to the problem
for boundary data that are constant on each connected component of the boundary of Ω. The Lagrangean L belongs to a class that contains both extended valued Lagrangeans and Lagrangeans with linear growth. Regularity means that the solution is Lipschitz continuous and that, in addition, is bounded.  相似文献   

3.
We consider the Cauchy problem for the Perona–Malik equation
in a bounded open set , with Neumann boundary conditions. If n = 1, we prove some a priori estimates on u and u x . Then we consider the semi-discrete scheme obtained by replacing the space derivatives by finite differences. Extending the previous estimates to the discrete setting we prove a compactness result for this scheme and we characterize the possible limits in some cases. Finally, for n > 1 we give examples to show that the corresponding estimates on are in general false.  相似文献   

4.
We consider the problem
where Ω is a bounded smooth domain in , 1  <  p< + ∞ if N = 2, if N ≥ 3 and ε is a parameter. We show that if the mean curvature of ∂Ω is not constant then, for ε small enough, such a problem has always a nodal solution u ε with one positive peak and one negative peak on the boundary. Moreover, and converge to and , respectively, as ε goes to zero. Here, H denotes the mean curvature of ∂Ω. Moreover, if Ω is a ball and , we prove that for ε small enough the problem has nodal solutions with two positive peaks on the boundary and arbitrarily many negative peaks on the boundary. The authors are supported by the M.I.U.R. National Project “Metodi variazionali e topologici nello studio di fenomeni non lineari”.  相似文献   

5.
In this note, we consider the problem
on a smooth bounded domain Ω in for p > 1. Let u p be a positive solution of the above problem with Morse index less than or equal to . We prove that if u p further satisfies the assumption as p → ∞, then the number of maximum points of u p is less than or equal to m for p sufficiently large. If Ω is convex, we also show that a solution of Morse index one satisfying the above assumption has a unique critical point and the level sets are star-shaped for p sufficiently large.   相似文献   

6.
We study the existence and uniqueness of solutions of the convective–diffusive elliptic equation
posed in a bounded domain , with pure Neumann boundary conditions
Under the assumption that with p = N if N ≥ 3 (resp. p > 2 if N  =  2), we prove that the problem has a solution if ∫Ω f dx  = 0, and also that the kernel is generated by a function , unique up to a multiplicative constant, which satisfies a.e. on Ω. We also prove that the equation
has a unique solution for all ν > 0 and the map is an isomorphism of the respective spaces. The study is made in parallel with the dual problem, with equation
The dependence on the data is also examined, and we give applications to solutions of nonlinear elliptic PDE with measure data and to parabolic problems.  相似文献   

7.
The aim of this paper is investigating the existence of one or more critical points of a family of functionals which generalizes the model problem
in the Banach space , being Ω a bounded domain in . In order to use “classical” theorems, a suitable variant of condition (C) is proved and is decomposed according to a “good” sequence of finite dimensional subspaces. The authors acknowledge the support of M.I.U.R. (research funds ex 40% and 60%).  相似文献   

8.
We prove some new a priori estimates for H 2-convex functions which are zero on the boundary of a bounded smooth domain Ω in a Carnot group . Such estimates are global and are geometric in nature as they involve the horizontal mean curvature of ∂Ω. As a consequence of our bounds we show that if has step two, then for any smooth H 2-convex function in vanishing on ∂Ω one has
. Supported in part by NSF Grant DMS-07010001.  相似文献   

9.
In this paper, we prove that if is a radially symmetric, sign-changing stationary solution of the nonlinear heat equation
in the unit ball of , N ≥ 3, with Dirichlet boundary conditions, then the solution of (NLH) with initial value blows up in finite time if |λ − 1| > 0 is sufficiently small and if α is subcritical and sufficiently close to 4/(N − 2). F. Dickstein was partially supported by CNPq (Brazil).  相似文献   

10.
We study C 2,1 nonnegative solutions u(x,t) of the nonlinear parabolic inequalities
in a punctured neighborhood of the origin in , when and . We show that a necessary and sufficient condition on λ for such solutions u to satisfy an a priori bound near the origin is , and in this case, the a priori bound on u is
This a priori bound for u can be improved by imposing an upper bound on the initial condition of u.  相似文献   

11.
In the present paper, the following Dirichlet problem and Neumann problem involving the p-Laplacian
((1.λ))
and
((2.λ))
are studied and some new multiplicity results of solutions for systems (1.λ) and (2.λ) are obtained. Moreover, by using the KKM principle we give also two new existence results of solutions for systems (1.1) and (2.1). This Work is supported in part by the National Natural Science Foundation of China (10561011).  相似文献   

12.
Solutions of elliptic problems with nonlinearities of linear growth   总被引:1,自引:0,他引:1  
In this paper, we study existence of nontrivial solutions to the elliptic equation
and to the elliptic system
where Ω is a bounded domain in with smooth boundary ∂Ω, , f (x, 0) = 0, with m ≥ 2 and . Nontrivial solutions are obtained in the case in which the nonlinearities have linear growth. That is, for some c > 0, for and , and for and , where I m is the m × m identity matrix. In sharp contrast to the existing results in the literature, we do not make any assumptions at infinity on the asymptotic behaviors of the nonlinearity f and . Z. Liu was supported by NSFC(10825106, 10831005). J. Su was supported by NSFC(10831005), NSFB(1082004), BJJW-Project(KZ200810028013) and the Doctoral Programme Foundation of NEM of China (20070028004).  相似文献   

13.
Consider a plate occupying in a reference configuration a bounded open set Ω ⊂ ℝ 2 , and let be its stored-energy function. In this paper we are concerned with relaxation of variational problems of type:
, where with is the scalar product in ℝ 3 and is the external loading per unit surface. We take into account the fact that an infinite amount of energy is required to compress a finite surface of the plate into zero surface, i.e.,
Mathematics Subject Classification (2000) 49J45  相似文献   

14.
In this paper, we prove that the weak solutions u∈Wloc^1, p (Ω) (1 〈p〈∞) of the following equation with vanishing mean oscillation coefficients A(x): -div[(A(x)△↓u·△↓u)p-2/2 A(x)△↓u+│F(x)│^p-2 F(x)]=B(x, u, △↓u), belong to Wloc^1, q (Ω)(A↓q∈(p, ∞), provided F ∈ Lloc^q(Ω) and B(x, u, h) satisfies proper growth conditions where Ω ∪→R^N(N≥2) is a bounded open set, A(x)=(A^ij(x)) N×N is a symmetric matrix function.  相似文献   

15.
Decomposition (or concentration-compactness) lemmas have already shown their efficience in order to show existence of minimizers or ground state solutions. The aim of this paper is to apply new version of these lemmas to minimisation problems involving Hardy–Sobolev type inequalities on a specific class of unbounded domains. More precisely, we shall find ground state solution for the following quotient, where value of real numbers ,b,q and are given.
We shall end this paper by establishing a decomposition lemma for cylindrical domains. More precisely, we shall find a minimizer for the following quantity:
Transmis par le Professeur H. Brezis.  相似文献   

16.
17.
Besides other things we prove that if , , locally minimizes the energy
, with N-functions a  ≤ b having the Δ2-property, then . Moreover, the condition
for all large values of t implies . If n = 2, then these results can be improved up to for all s < ∞ without the hypothesis . If n ≥ 3 together with M = 1, then higher integrability for any exponent holds under more restrictive assumptions than .   相似文献   

18.
The solution u of the well-posed problem
depends continuously on (a ij ,β,γ,q). Dedicated to Karl H. Hofmann on his 75th birthday.  相似文献   

19.
In the Heisenberg group framework, we obtain a geometric inequality for stable solutions of in a domain . More precisely, if we denote the horizontal intrinsic Hessian by Hu, the mean curvature of a level set by h, its imaginary curvature by p, the intrinsic normal by ν and the unit tangent by υ, we have that
for any . Stable solutions in the entire satisfying a suitably weighted energy growth and such that are then shown to have level sets with vanishing mean curvature. F. Ferrari is partially supported by GALA project Geometric Analysis in Lie groups and Applications, supported by the European Commission within the 6th Framework Programme and by the PRIN project Viscosity, metric and control theoretic methods in nonlinear partial differential equations, MIUR (Italy). E. Valdinoci is partially supported by the PRIN project Variational Methods and Nonlinear Differential Equations, MIUR (Italy).  相似文献   

20.
We study the limit as n goes to +∞ of the renormalized solutions u n to the nonlinear elliptic problems
where Ω is a bounded open set of ℝ N , N≥ 2, and μ is a Radon measure with bounded variation in Ω. Under the assumption of G-convergence of the operators , defined for , to the operator , we shall prove that the sequence (u n ) admits a subsequence converging almost everywhere in Ω to a function u which is a renormalized solution to the problem
  相似文献   

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