共查询到20条相似文献,搜索用时 281 毫秒
1.
We examine the regularity of weak solutions of quasi-geostrophic (QG) type equations with supercritical (α<1/2) dissipation α(−Δ). This study is motivated by a recent work of Caffarelli and Vasseur, in which they study the global regularity issue for the critical (α=1/2) QG equation [L. Caffarelli, A. Vasseur, Drift diffusion equations with fractional diffusion and the quasi-geostrophic equation, arXiv: math.AP/0608447, 2006]. Their approach successively increases the regularity levels of Leray–Hopf weak solutions: from L2 to L∞, from L∞ to Hölder (Cδ, δ>0), and from Hölder to classical solutions. In the supercritical case, Leray–Hopf weak solutions can still be shown to be L∞, but it does not appear that their approach can be easily extended to establish the Hölder continuity of L∞ solutions. In order for their approach to work, we require the velocity to be in the Hölder space C1−2α. Higher regularity starting from Cδ with δ>1−2α can be established through Besov space techniques and will be presented elsewhere [P. Constantin, J. Wu, Regularity of Hölder continuous solutions of the supercritical quasi-geostrophic equation, Ann. Inst. H. Poincaré Anal. Non Linéaire, in press]. 相似文献
2.
We study the large time behavior of solutions of the Cauchy problem for the Hamilton–Jacobi equation ut+H(x,Du)=0 in Rn×(0,∞), where H(x,p) is continuous on Rn×Rn and convex in p . We establish a general convergence result for viscosity solutions u(x,t) of the Cauchy problem as t→∞. 相似文献
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Let K be a closed convex subset of a q-uniformly smooth separable Banach space, T:K→K a strictly pseudocontractive mapping, and f:K→K an L-Lispschitzian strongly pseudocontractive mapping. For any t∈(0,1), let xt be the unique fixed point of tf+(1-t)T. We prove that if T has a fixed point, then {xt} converges to a fixed point of T as t approaches to 0. 相似文献
4.
Alan D. Sokal 《Expositiones Mathematicae》2010,28(2):179-185
We obtain a characterization of generalized Stieltjes functions of any order λ>0 in terms of inequalities for their derivatives on (0,∞). When λ=1, this provides a new and simple proof of a characterization of Stieltjes functions first obtained by Widder in 1938. 相似文献
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In this paper, we consider the problem (Pε) : Δ2u=un+4/n-4+εu,u>0 in Ω,u=Δu=0 on ∂Ω, where Ω is a bounded and smooth domain in Rn,n>8 and ε>0. We analyze the asymptotic behavior of solutions of (Pε) which are minimizing for the Sobolev inequality as ε→0 and we prove existence of solutions to (Pε) which blow up and concentrate around a critical point of the Robin's function. Finally, we show that for ε small, (Pε) has at least as many solutions as the Ljusternik–Schnirelman category of Ω. 相似文献
6.
We study the problem of propagation of analytic regularity for semi-linear symmetric hyperbolic systems. We adopt a global perspective and we prove that if the initial datum extends to a holomorphic function in a strip of radius (= width) ε0, the same happens for the solution u(t,⋅) for a certain radius ε(t), as long as the solution exists. Our focus is on precise lower bounds on the spatial radius of analyticity ε(t) as t grows. 相似文献
7.
We present a regularity result for weak solutions of the 2D quasi-geostrophic equation with supercritical (α<1/2) dissipation α(−Δ): If a Leray–Hopf weak solution is Hölder continuous θ∈Cδ(R2) with δ>1−2α on the time interval [t0,t], then it is actually a classical solution on (t0,t]. 相似文献
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In the well-known work of P.-L. Lions [The concentration–compactness principle in the calculus of variations, The locally compact case, part 1. Ann. Inst. H. Poincaré, Analyse Non Linéaire 1 (1984) 109–1453] existence of positive solutions to the equation -Δu+u=b(x)up-1, u>0, u∈H1(RN), p∈(2,2N/(N-2)) was proved under assumption b(x)?b∞?lim|x|→∞b(x). In this paper we prove the existence for certain functions b satisfying the reverse inequality b(x)<b∞. For any periodic lattice L in RN and for any b∈C(RN) satisfying b(x)<b∞, b∞>0, there is a finite set Y⊂L and a convex combination bY of b(·-y), y∈Y, such that the problem -Δu+u=bY(x)up-1 has a positive solution u∈H1(RN). 相似文献
10.
An approximate martingale estimating function with an eigenfunction is proposed for an estimation problem about an unknown drift parameter for a one-dimensional diffusion process with small perturbed parameter ε from discrete time observations at n regularly spaced time points k/n, k=0,1,…,n. We show asymptotic efficiency of an M-estimator derived from the approximate martingale estimating function as ε→0 and n→∞ simultaneously. 相似文献
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Gautam Iyer Tomasz Komorowski Alexei Novikov Lenya Ryzhik 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2014
We consider an elliptic eigenvalue problem with a fast cellular flow of amplitude A , in a two-dimensional domain with L2 cells. For fixed A , and L→∞, the problem homogenizes, and has been well studied. Also well studied is the limit when L is fixed, and A→∞. In this case the solution equilibrates along stream lines. 相似文献
13.
By a perturbation method and constructing comparison functions, we reveal how the inhomogeneous term h affects the exact asymptotic behaviour of solutions near the boundary to the problem △u=b(x)g(u)+λh(x), u>0 in Ω, u|∂Ω=∞, where Ω is a bounded domain with smooth boundary in RN, λ>0, g∈C1[0,∞) is increasing on [0,∞), g(0)=0, g′ is regularly varying at infinity with positive index ρ, the weight b, which is non-trivial and non-negative in Ω, may be vanishing on the boundary, and the inhomogeneous term h is non-negative in Ω and may be singular on the boundary. 相似文献
14.
We consider an interacting particle Markov process for Darwinian evolution in an asexual population with non-constant population size, involving a linear birth rate, a density-dependent logistic death rate, and a probability μ of mutation at each birth event. We introduce a renormalization parameter K scaling the size of the population, which leads, when K→+∞, to a deterministic dynamics for the density of individuals holding a given trait. By combining in a non-standard way the limits of large population (K→+∞) and of small mutations (μ→0), we prove that a timescale separation between the birth and death events and the mutation events occurs and that the interacting particle microscopic process converges for finite dimensional distributions to the biological model of evolution known as the “monomorphic trait substitution sequence” model of adaptive dynamics, which describes the Darwinian evolution in an asexual population as a Markov jump process in the trait space. 相似文献
15.
João Marcos do Ó Manassés de SouzaEveraldo de Medeiros Uberlandio Severo 《Journal of Differential Equations》2014
In line with the Concentration–Compactness Principle due to P.-L. Lions [19], we study the lack of compactness of Sobolev embedding of W1,n(Rn), n?2, into the Orlicz space LΦα determined by the Young function Φα(s) behaving like eα|s|n/(n−1)−1 as |s|→+∞. In the light of this result we also study existence of ground state solutions for a class of quasilinear elliptic problems involving critical growth of the Trudinger–Moser type in the whole space Rn. 相似文献
16.
We study the existence of solutions u:R3→R2 for the semilinear elliptic systems where W:R2→R is a double well symmetric potential. We use variational methods to show, under generic non-degenerate properties of the set of one dimensional heteroclinic connections between the two minima a± of W, that (0.1) has infinitely many geometrically distinct solutions u∈C2(R3,R2) which satisfy u(x,y,z)→a± as x→±∞ uniformly with respect to (y,z)∈R2 and which exhibit dihedral symmetries with respect to the variables y and z . We also characterize the asymptotic behavior of these solutions as |(y,z)|→+∞. 相似文献
equation(0.1)
−Δu(x,y,z)+∇W(u(x,y,z))=0,
17.
The article is devoted to the representation theory of locally compact infinite-dimensional group GLB of almost upper-triangular infinite matrices over the finite field with q elements. This group was defined by S.K., A.V., and Andrei Zelevinsky in 1982 as an adequate n=∞ analogue of general linear groups GL(n,q). It serves as an alternative to GL(∞,q), whose representation theory is poor. 相似文献
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We consider a U(1)-invariant nonlinear Klein–Gordon equation in dimension n?1, self-interacting via the mean field mechanism. We analyze the long-time asymptotics of finite energy solutions and prove that, under certain generic assumptions, each solution converges as t→±∞ to the two-dimensional set of all “nonlinear eigenfunctions” of the form ?(x)e−iωt. This global attraction is caused by the nonlinear energy transfer from lower harmonics to the continuous spectrum and subsequent dispersive radiation. 相似文献