We prove that C2+α,1+α/2 (Q?) solutions of problem (1.6) below are in a subspace Hcm+2(Q) of Hm+2,(m+2)/2(Q) for all m ∈ ?, if f and the coefficients are in Hcm(Q)∪Cα,α/2 (Q?). We apply this result to obtain global existence of Sobolev solutions to the quasilinear problem (1.26) below. 相似文献
Let Ω be an open set in Euclidean space ?m with finite perimeter ${\mathcal{P}}(\Omega),$ and with m-dimensional Lebesgue measure |Ω|. It was shown by M. Preunkert that if T(t) is the heat semigroup on L2(?m) then $H_{\Omega}(t):=\int_{\Omega}T(t)\textbf{1}_{\Omega}(x)dx=|\Omega|-\pi^{-1/2}{\mathcal{P}}(\Omega)t^{1/2}+o(t^{1/2}), \ t\downarrow 0$. HΩ(t) represents the amount of heat in Ω if Ω is at initial temperature 1 and if ?m???Ω is at initial temperature 0. In this paper we will compare the quantitative behaviour of HΩ(t) with the usual heat content QΩ(t) associated to the Dirichlet heat semigroup on Ω. We analyse the heat content for horn-shaped open sets of the form Ω(α, Σ)?=?{(x, x′)?∈??m: x′?∈?(1?+?x)???αΣ, x?>?0}, where α?>?0, and where Σ is an open set in ?m???1 with finite perimeter in ?m???1, which is star-shaped with respect to 0. For m?≥?3 we find that there are four regimes with very different behaviour depending on α, and a further two limiting cases where logarithmic corrections appear. 相似文献
Let Ω be an open set in ?N(N ? 3), with compact boundary ?Ω of type C1,α(?(0,1)). We show that the single layer potential Ef, related to the stationary Stokes system on Ω, belongs to C1,α(?Ω)N, provided the source density f belongs to Cα(?Ω)N. In addition, we prove a related estimate of the function E(f)?Ω and its tangential derivatives. 相似文献
We prove that if X is a Stein complex manifold of dimension n and Ω???X a locally q-complete open set in X with q?≤?n?2, then the cohomology groups Hp(Ω , OΩ) vanish if p?≥?q and OΩ is the sheaf of germs of holomorphic functions on Ω. 相似文献
We prove that the solution of the oblique derivative parabolic problem in a noncylindrical domain ΩT belongs to the anisotropic Holder space C2+α, 1+α/2(gwT) 0 < α < 1, even if the nonsmooth “lateral boundary” of ΩT is only of class C1+α, (1+α)/2). As a corollary, we also obtain an a priori estimate in the Hölder space C2+α(Ω0) for a solution of the oblique derivative elliptic problem in a domain Ω0 whose boundary belongs only to the classe C1+α. 相似文献
Let Γ be a free nonabelian group on finitely many generators. Let Ω be the boundary of Γ, letC(Ω) be theC*-algebra of continuous functions on Ω, and let λ be the natural action of Γ onC(Ω). Aboundary representation is a representation of the crossed productC*-algebra Γ×λC(Ω). Given a unitary representation π of Γ onH, aboundary realization of π is an isometric Γ-inclusion ofH into the space of a boundary representation whose image is cyclic for that boundary representation. If the Γ-inclusion is bijective, we call, the realizationperfect. We prove below that if π admits an imperfect boundary realization, then there exists a nonzero vectorv0∈H satisfying $$\sum\limits_{|x| = n} {|\left\langle {v,\pi (x)v_0 } \right\rangle |^2 \leqslant |v|^2 } for each v \in {\mathcal{H}} (GVB)$$ If π is irreducible and weakly contained in the regular representation, and if no suchv0 exists, it follows that π satisfiesmonotony: up to equivalence, there exists exactly one realization of π, and that realization is perfect. 相似文献
In this paper, we are concerned with the classification of operators on complex separable Hilbert spaces, in the unitary equivalence sense and the similarity sense, respectively. We show that two strongly irreducible operators A and B are unitary equivalent if and only if W*(A+B)′≈M2(C), and two operators A and B in B1(Ω) are similar if and only if A′(AGB)/J≈M2(C). Moreover, we obtain V(H^∞(Ω,μ)≈N and Ko(H^∞(Ω,μ)≈Z by the technique of complex geometry, where Ω is a bounded connected open set in C, and μ is a completely non-reducing measure on Ω. 相似文献
We study the function Λm(X), 0<m<1, of compact setsX in ℝn, n≥2, defined as the distance in the spaceCm(X)≡lipm(X) from the function |x|2 to the subspaceHm(X) which is the closure inCm(X) of the class of functions harmonic in the neighborhood ofX (each function in its own neighborhood). We prove the equivalence of the conditions Λm(X)=0 andCm(X)=Hm(X). We derive an estimate from above that depends only on the geometrical properties of the setX (on its volume).
Translated fromMatematicheskie Zametki, Vol. 62, No. 3, pp. 372–382, September, 1997.
Translated by I. P. Zvyagin 相似文献
We investigate the Cauchy problem for linear elliptic operators with C∞–coefficients at a regular set Ω ? R2, which is a classical example of an ill-posed problem. The Cauchy data are given at the manifold Γ ? ?Ω and our goal is to reconstruct the trace of the H1(Ω) solution of an elliptic equation at ?Ω/Γ. The method proposed here composes the segmenting Mann iteration with a fixed point equation associated with the elliptic Cauchy problem. Our algorithm generalizes the iterative method developed by Maz'ya et al., who proposed a method based on solving successive well-posed mixed boundary value problems. We analyze the regularizing and convergence properties both theoretically and numerically. 相似文献
Let (m, n) ∈ ℕ2, Ω an open bounded domain in ℝm, Y = [0, 1]m; uε in (L2(Ω))n which is two-scale converges to some u in (L2(Ω × Y))n. Let φ: Ω × ℝm × ℝn → ℝ such that: φ(x, ·, ·) is continuous a.e. x ∈ Ω φ(·, y, z) is measurable for all (y, z) in ℝm × ℝn, φ(x, ·, z) is 1-periodic in y, φ(x, y, ·) is convex in z. Assume that there exist a constant C1 > 0 and a function C2 ∈ L2(Ω) such that
In this article, the authors establish the conditions for the extinction of solutions, in finite time, of the fast diffusive polytropic filtration equation ut?=?div(|?um|p?2?um)?+?a∫Ωuq(y,?t)dy with a, q, m?>?0, p?>?1, m(p???1)?1, in a bounded domain Ω???RN (N?>?2). More precisely speaking, it is shown that if q?>?m(p???1), any non-negative solution with small initial data vanishes in finite time, and if 0?q?m(p???1), there exists a solution which is positive in Ω for all t?>?0. For the critical case q?=?m(p???1), whether the solutions vanish in finite time or not depends on the comparison between a and μ, where μ?=?∫?Ωφp?1(x)dx and φ is the unique positive solution of the elliptic problem ?div(|?φ|p?2?φ)?=?1, x?∈?Ω; φ(x)?=?0, x?∈??Ω. 相似文献
Let L0(ΩA,P) be the space of equivalent classes of random variables defined on a probability space (Ω,A,P). Let H be the closed subspace of L0(Ω,A,P) spanned by a sequence of i.i.d. (independent and identically distributed) random variables having the symmetric nondegenerate law F. It is proved that H is linearly homeomorphic to lp for 0<p≤2 if F belongs to the domain of normal attraction of symmetric stable law withexponent p. 相似文献