where λR+:=[0,∞), and satisfies the conditions
We prove a strong maximum principle for the linear operator defined by the left-hand side of (1), and use this to show that for every solution (λ,u) of (1)–(2), u is positive on Ta,b . In addition, we show that there exists λmax>0 (possibly λmax=∞), such that, if 0λ<λmax then (1)–(2) has a unique solution u(λ), while if λλmax then (1)–(2) has no solution. The value of λmax is characterised as the principal eigenvalue of an associated weighted eigenvalue problem (in this regard, we prove a general existence result for such eigenvalues for problems with general, nonnegative weights).  相似文献   

4.
Some Aspects of Lw1^r (G)∩ L(p,q, w2dμ)(G)     
Ilker ERYILMAZ  Cenap DUYAR 《数学年刊B辑(英文版)》2009,30(3):311-320
Let G be a locally compact Abelian group with Haar measure. The authors discuss some basic properties of Lw1^r (G)∩ L(p, q, w2dμ)(G) spaces. Then the necessary conditions for compact embeddings of the spaces Lw1^r (R^d)∩ L(p, q, w2dμ)(R^d) are showed.  相似文献   

5.
The Cauchy Integral Operator on Weighted Hardy Space     
Jianmiao RUAN  Jiecheng CHEN 《数学年刊B辑(英文版)》2010,31(4):461-472
The authors show that the Cauchy integral operator is bounded from Hωp(R1) to hωp(R1) (the weighted local Hardy space). To prove the results, a kind of generalized atoms is introduced and a variant of weighted "Tb theorem" is considered.  相似文献   

6.
A short note on weighted mean matrices     
Niranjan Singh  Neeta Sharma 《Proceedings Mathematical Sciences》1999,109(3):303-307
In the present paper we have established a relation between (N, p n ) and (N, q n ) weighted mean matrices, when considered as bounded operators on 1p, 1 < p < ∞.  相似文献   

7.
Weighted Composition Operators Between Weighted Bloch Type Spaces and Weighted Banach Spaces of Holomorphic Functions     
Elke Wolf 《Numerical Functional Analysis & Optimization》2013,34(5-6):646-651
Let φ: 𝔻 → 𝔻 and ψ: 𝔻 → ? be analytic maps. They induce a weighted composition operator ψ C φ acting between weighted Bloch type spaces and weighted Banach spaces of holomorphic functions. Under some assumptions on the weights, we give a necessary as well as a sufficient condition when such an operator is bounded resp. compact.  相似文献   

8.
The Fefferman-Stein-Type Inequality for the Kakeya Maximal Operator II     
Hitoshi Tanaka 《数学学报(英文版)》2002,18(3):447-454
Let K δ, 0 < δ≪1, be the Kakeya maximal operator defined as the supremum of averages over tubes of the eccentricity δ. The (so-called) Fefferman-Stein-type inequality: is shown, where C d and α d are constants depending only on the dimension d and w is a weight. The result contains the exponent (d−2)/2d which is smaller than the exponent (d−2)(d−1)/d(2d−3) obtained in [7]. Received October 8, 2001, Accepted February 28, 2002  相似文献   

9.
Management and analysis of DNA microarray data by using weighted trees     
Trang Tran  Cam Chi Nguyen  Ngoc Minh Hoang 《Journal of Global Optimization》2007,39(4):623-645
We investigate discrete structures and combinatoric modeling of weighted prefix trees for managing and analyzing DNA microarray data. We describe the algorithms to construct the weighted trees for these data. Using these weighted trees with our algorithms, we propose methods to compute the appearance probability of a DNA microarray, to compare the informational distances in the expression of genes between the DNA microarrays, to search the characteristic microarrays and the group of candidate genes suggestive of a pathology.  相似文献   

10.
A Degenerate Fourth-Order Parabolic Equation Modeling Bose-Einstein Condensation Part II: Finite-Time Blow-Up     
Ansgar Jüngel  Michael Winkler 《偏微分方程通讯》2015,40(9):1748-1786
A degenerate fourth-order parabolic equation modeling condensation phenomena related to Bose-Einstein particles is analyzed. The model can be motivated from the spatially homogeneous and isotropic Boltzmann-Nordheim equation by a formal Taylor expansion of the collision integral. It maintains some of the main features of the kinetic model, namely mass and energy conservation and condensation at zero energy. The existence of local-in-time weak solutions satisfying a certain entropy inequality is proven. The main result asserts that if a weighted L 1 norm of the initial data is sufficiently large and the initial data satisfies some integrability conditions, the solution blows up with respect to the L norm in finite time. Furthermore, the set of all such blow-up enforcing initial functions is shown to be dense in the set of all admissible initial data. The proofs are based on approximation arguments and interpolation inequalities in weighted Sobolev spaces. By exploiting the entropy inequality, a nonlinear integral inequality is proved which implies the finite-time blow-up property.  相似文献   

11.
Intelligent variable orderings and re-orderings in DAC-based solvers for WCSP     
Federico Heras  Javier Larrosa 《Journal of Heuristics》2006,12(4-5):287-306
Weighted constraint satisfaction problems (WCSPs) is a well-known framework for combinatorial optimization problems with several domains of application. In the last few years, several local consistencies for WCSPs have been proposed. Their main use is to embed them into a systematic search, in order to detect and prune unfeasible values as well as to anticipate the detection of deadends. Some of these consistencies rely on an order among variables but nothing is known about which orders are best. Therefore, current implementations use the lexicographic order by default. In this paper we analyze the effect of heuristic orders at three levels of increasing overhead: i) compute the order prior to search and keep it fixed during the whole solving process (we call this a static order), ii) compute the order at every search node using current subproblem information (we call this a dynamic order) and iii) compute a sequence of different orders at every search node and sequentially enforce the local consistency for each one (we call this dynamic re-ordering). We performed experiments in three different problems: Max-SAT, Max-CSP and warehouse location problems. We did not find an alternative better than the rest for all the instances. However, we found that inverse degree (static order), sum of unary weights (dynamic order) and re-ordering with the sum of unary weights are good heuristics which are always better than a random order. This research is supported by the MEC through project TIC-2002-04470-C03.  相似文献   

12.
Weighted Davenport’s constant and the weighted EGZ Theorem     
Xiangneng Zeng  Pingzhi Yuan 《Discrete Mathematics》2011,(17):1940
Let G,G be finite abelian groups with nontrivial homomorphism group . Let Ψ be a non-empty subset of . Let DΨ(G) denote the minimal integer, such that any sequence over G of length DΨ(G) must contain a nontrivial subsequence s1,…,sr, such that for some ψiΨ. Let EΨ(G) denote the minimal integer such that any sequence over G of length EΨ(G) must contain a nontrivial subsequence of length |G|,s1,…,s|G|, such that for some ψiΨ. In this paper, we show that EΨ(G)=|G|+DΨ(G)−1.  相似文献   

13.
14.
On the Propagation of Regularity and Decay of Solutions to the k-Generalized Korteweg-de Vries Equation     
Pedro Isaza  Gustavo Ponce 《偏微分方程通讯》2015,40(7):1336-1364
We study special regularity and decay properties of solutions to the IVP associated to the k-generalized KdV equations. In particular, for datum u 0 ∈ H 3/4+ (?) whose restriction belongs to H l ((b, ∞)) for some l ∈ ?+ and b ∈ ? we prove that the restriction of the corresponding solution u(·, t) belongs to H l ((β, ∞)) for any β ∈ ? and any t ∈ (0, T). Thus, this type of regularity propagates with infinite speed to its left as time evolves.  相似文献   

15.
On the existence of bounded noncontinuable solutions     
Miroslav Bartušek 《Mathematische Nachrichten》2010,283(6):805-817
This paper presents necessary and sufficient conditions for an n ‐th order differential equation to have a non‐continuable solution with finite limits of its derivatives up to the order l at the right‐hand end point of the interval of its definition, ln – 2 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

16.
Online weighted flow time and deadline scheduling   总被引:1,自引:0,他引:1  
Luca Becchetti  Stefano Leonardi  Alberto Marchetti-Spaccamela  Kirk Pruhs   《Journal of Discrete Algorithms》2006,4(3):339
In this paper we study some aspects of weighted flow time. We first show that the online algorithm Highest Density First is an O(1)-speed O(1)-approximation algorithm for P|ri,pmtn|∑wiFi. We then consider a related Deadline Scheduling Problem that involves minimizing the weight of the jobs unfinished by some unknown deadline D on a uniprocessor. We show that any c-competitive online algorithm for weighted flow time must also be c-competitive for deadline scheduling. We then give an O(1)-competitive algorithm for deadline scheduling.  相似文献   

17.
18.
A Fan Type Condition For Heavy Cycles in Weighted Graphs   总被引:2,自引:0,他引:2  
Shenggui Zhang  Hajo Broersma  Xueliang Li  Ligong Wang 《Graphs and Combinatorics》2002,18(1):193-200
 A weighted graph is a graph in which each edge e is assigned a non-negative number w(e), called the weight of e. The weight of a cycle is the sum of the weights of its edges. The weighted degree d w (v) of a vertex v is the sum of the weights of the edges incident with v. In this paper, we prove the following result: Suppose G is a 2-connected weighted graph which satisfies the following conditions: 1. max{d w (x),d w (y)∣d(x,y)=2}≥c/2; 2. w(x z)=w(y z) for every vertex zN(x)∩N(y) with d(x,y)=2; 3. In every triangle T of G, either all edges of T have different weights or all edges of T have the same weight. Then G contains either a Hamilton cycle or a cycle of weight at least c. This generalizes a theorem of Fan on the existence of long cycles in unweighted graphs to weighted graphs. We also show we cannot omit Condition 2 or 3 in the above result. Received: February 7, 2000 Final version received: June 5, 2001  相似文献   

19.
Function Spaces with Exponential Weights II     
Thomas Schott 《Mathematische Nachrichten》1998,196(1):231-250
This paper is a continuation of [8]. We study weighted function spaces of type B and F on the Euclidean space Rn, where u is a weight function of at most exponential growth. In particular, u(χ (±|χ|) is an admissible weight. We deal with atomic decompositions of these spaces. Furthermore, we prove that the spaces B and F are isomorphic to the corresponding unweighted spaces B and F.  相似文献   

20.
On weighted inequalities for martingale transform operators     
Teresa Martínez 《Mathematische Nachrichten》2003,251(1):52-63
For 1 < p < ∞, the almost surely finiteness of is a necessary and sufficient condition in order to have almost surely convergence of the sequences {E(f|?n)} with fLp(v dP). This condition is also equivalent to have weighted inequalities from Lp(v dP) into Lp(u dP) for some weight u for Doob's maximal function, square function and generalized Burkholder martingale transforms. Similarly, E(u|?1) < ∞ turns out to be necessary and sufficient for the above weighted inequalities to hold for some v.  相似文献   

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By using ‘summable‘ dichotomies and fixed point theorems we prove the existence of convergent and bounded solutions of nonlinear difference systems.  相似文献   

3.
Let TR be a time-scale, with a=infT, b=supT. We consider the nonlinear boundary value problem
(2)
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u(a)=u(b)=0,
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