共查询到20条相似文献,搜索用时 31 毫秒
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We consider the Helmholtz equation with a variable index of refraction n(x), which is not necessarily constant at infinity but can have an angular dependency like n(x)→n∞(x/|x|) as |x|→∞. We prove that the Sommerfeld condition at infinity still holds true under the weaker form Our approach consists in proving this estimate in the framework of the limiting absorbtion principle. We use Morrey–Campanato type of estimates and a new inequality on the energy decay, namely It is a striking feature that the index n∞ appears in this formula and not the phase gradient, in apparent contradiction with existing literature. To cite this article: B. Perthame, L. Vega, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
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M.Francesca Betta Friedman Brock Anna Mercaldo M.Rosaria Posteraro 《Comptes Rendus Mathematique》2002,334(6):451-456
In this paper we prove a comparison result for weak solutions to linear elliptic problems of the type where is an open set of (n?2), ?(x)=(2π)?n/2exp(?|x|2/2), aij(x) are measurable functions such that aij(x)ξiξj??(x)|ξ|2 a.e. , and f(x) is a measurable function taken in order to guarantee the existence of a solution of (1.1). We use the notion of rearrangement related to Gauss measure to compare u(x) with the solution of a problem of the same type, whose data are defined in a half-space and depend only on one variable. To cite this article: M.F. Betta et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 451–456. 相似文献
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Augusto C. Ponce 《Comptes Rendus Mathematique》2003,337(4):253-257
We show that if , is a bounded Lipschitz domain and is a sequence of nonnegative radial functions weakly converging to δ0 then there exist C>0 and n0?1 such that The above estimate was suggested by some recent work of Bourgain, Brezis and Mironescu (in: Optimal Control and Partial Differential Equations, IOS Press, 2001, pp. 439–455). As n→∞ in (1) we recover Poincaré's inequality. We also extend a compactness result of Bourgain, Brezis and Mironescu. To cite this article: A.C. Ponce, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
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We consider prenormal forms associated to generic perturbations of the system . It is known that they have a formal normal form , where [Differential Equations 158 (1) (1999) 152–173]. We show that the series A0 and the normalizing transformations are divergent, but 1-summable. To cite this article: M. Canalis-Durand, R. Schäfke, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
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Juan Rivera-Letelier 《Comptes Rendus Mathematique》2002,335(5):441-446
We prove that a non constant holomorphic function f defined over an analytic subspace of is injective if and only if This characterization proves the analogue, for holomorphic functions, of a conjecture of A. Escassut and M.C. Sarmant. On the other hand we give a counter-example to this conjecture, that concerns bi-analytic elements. To cite this article: J. Rivera-Letelier, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 441–446. 相似文献
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《European Journal of Operational Research》2002,143(2):365-376
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《Nonlinear Analysis: Theory, Methods & Applications》2003,54(1):9-37
In this paper, we study the problemin the setting of the weighted sobolev space . The main novelty of our work is L∞ estimates on the solutions, and the existence of a weak and renormalized solution. 相似文献
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M.Francesca Betta Anna Mercaldo François Murat M.Michaela Porzio 《Comptes Rendus Mathematique》2002,334(9):757-762
In this Note we consider a class of noncoercive nonlinear problems whose prototype is where is a bounded open subset of (N?2), △p is the so called p-Laplace operator (1<p<N) or a variant of it, μ is a Radon measure with bounded variation on or a function in , λ?0 and b belongs to the Lorentz space or to the Lebesgue space . We prove existence and uniqueness of renormalized solutions. To cite this article: M.F. Betta et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 757–762. 相似文献