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1.
§1. IntroductionRecently,thesemilinearellipticequations△u+f(u)=0(1.1)u(x)→0as|x|→∞(1.2)inRnwereconsideredwidely(see[1]-[7]).Inthenicepapers[1]and[2],itwasprovedthatanypositivesolutionof(1.1)mustberadialincasef(u)∈C1+δ(δ>0).Therefore,anypositivesoluti…  相似文献   

2.
§1. IntroductionIn1908,E.Landauintroducedthefollowingwellknownsequenceofoperators[1]Ln[f(t);x]=Kn∫1-1f(t)[1-(t-x)2]ndt,    (1.1)where     Kn=[∫1{-1(1-t2)ndt]-1~nπ  (n→∞).(1.1)wasusedintheproofoftheWeierstrassTheorem.Sincethen,theapproximationprop-ert…  相似文献   

3.
王书彬  吕延华 《数学季刊》1998,13(3):102-110
§1. IntroductionIn[1,2],AronsonandWeinbergerhavestudiedsystematiclythescalarnonlineardiffu-sionequationinonespacevariableut=uxx+φ(u),(1.1)whereu=u(x,t)andφ(u)isanonlinearfunction.Equation(1.1)arisesinseveralapplica-tions;See[1,2]and[3]forinformationa…  相似文献   

4.
关于可分解算子的扰动的不变子空间(英文)   总被引:1,自引:0,他引:1  
在文献[1]中,J.Eschmeier和B.Prunaru证明了(复)Banach空间上的每个具有Bishop性质(β)和浓厚谱的有界线性算子有非平凡的不变子空间.在文献[2]中,H.Mohebi和M.Radjabalipour在减弱算子的Bishop性质(β)和加强谱的浓厚性条件的情况下得到了另外几个不变子空间定理.本文给出了一个更进一步的不变子空间定理(见定理1).  相似文献   

5.
§1. IntroductionThecommonchemostatmodelhasbeenconsideredbymanymathematians(see[1]).Chemostatmodelsincorporatingdiscretetimedelayhavebeeninvestigatedin[2]and[3].In[4]and[5],chemostatmodelswithcontinuoustimedelayinnutrientrecyclingwereconsid-ered.Inthi…  相似文献   

6.
§1. IntroductionIfD1,D2aretwosmoothboundedpseudoconvexdomainsinCn,D1satisfiestheconditionR(see[1]),itiswellknownthatanybiholomorphicmappingf:D1→D2extendssmoothlytotheboundary.Thisresulthasbeengeneralizedtothecasesofproperholomorphicmappings([2]).Inth…  相似文献   

7.
闫宝强 《数学季刊》1998,13(1):55-60
§1. IntroductionItiswellknownthatthedegreetheoryforak-set-contractoperatorhasmanyapplicationsontheexistenceofthesolutionsofsomeequations(see[1],[2],[3]).However,someopera-torsarenotk-set-contractoperators.Itisanewproblemthatweestablishadegreetheoryfo…  相似文献   

8.
Banach空间中广义正交分解定理与广义正交可补子空间   总被引:22,自引:1,他引:21  
王玉文  王辉 《数学学报》2001,44(6):1045-105
本文首先将 Hilbert空间中的Riesz正交分解定理推广到 Banach空间,得到 Banach空间广义正交分解定理.然后,利用此定理讨论由James R.C.[1]引入的Banach空间中正交概念及 Nashed M.Z.[2]引入的 Banach空间中(广义)正交可补子空间,得到判别子空间广义正交可补的充分必要条件,并由此给出Hilbert空间的一个新特征.  相似文献   

9.
LetRbeaG-gradedringwithidentity1;thatisRg∈GRgandRgRhRghforallg,h∈G.TheassociativeringR#GdenotesthesmashproductforthegroupGandthegradedringR(see[3]or[4]).In[1],CohenandMontgomeryprovedthedualityTheoremsforactionsandcoactionsforfinitegroupG.In[2],af…  相似文献   

10.
ItiswellknownthatthemethodtoconstructwaveletismultiresolutionanalysiswhichwasgivenfirstbyS.Mallat([1],[2])in1989.In1994,T.N.T.GoodmanandS.L.Lee([3])generalizedconceptofmultiresolutionanalysistothecaseofmultiphcityr(r1)suchthatmultiwaveletscanbeconst…  相似文献   

11.
This paper provides decomposition algorithms for locating minimal cuts in a large directed network. The main theorem provides several cases for the algorithms. In the worst case, it is shown that the efficiency of one of the proposed algorithms is of the same order as a no-decomposition algorithm. As in linear programming, the obvious advantage of the proposed decomposition procedure is its ability to potentially handle larger problems than a no-decomposition algorithm.  相似文献   

12.
We prove the cut-elimination theorem, Gentzen's Hauptsatz, for the system for stratified comprehension, i. e. Quine's NF minus extensionality. Mathematics Subject Classification: 03B15, 03F05.  相似文献   

13.
几种新的截集及其应用   总被引:21,自引:1,他引:20  
本文从“邻域”和“重域”的观点出发引入了三种新的截集:下截集,下重截集和上重截集。我们给出这些截集的性质及相应的分解定理,表现定理和扩展原理,作为应用,我们讨论了两方面的内容;一是利用落影表现理论,将一个模糊集看作“重云”的落影,然后用下生截集和落影表现理论来定义模糊集的运算,得到了与“2”一致的结果。  相似文献   

14.
In this article, a cut‐free system TLMω1 for infinitary propositional modal logic is proposed which is complete with respect to the class of all Kripke frames.The system TLMω1 is a kind of Gentzen style sequent calculus, but a sequent of TLMω1 is defined as a finite tree of sequents in a standard sense. We prove the cut‐elimination theorem for TLMω1 via its Kripke completeness.  相似文献   

15.
一类新的KKM定理及其应用*   总被引:1,自引:0,他引:1  
本文得到一类新的KKM定理,统一和改进了[2,3,0,7,11]中的结果。作为应用,我们得到了几个匹配定理、重合定理、不动点定理、极大极小不等式定理及截口定理。  相似文献   

16.
A cycle cover (cut cover) of a graph G is a collection of cycles (cuts) of G that covers every edge of G at least once. The total size of a cycle cover (cut cover) is the sum of the number of edges of the cycles (cuts) in the cover.We discuss several results for cycle covers and the corresponding results for cut covers. Our main result is that every connected graph on n vertices and e edges has a cut cover of total size at most 2e-n+1 with equality precisely when every block of the graph is an odd cycle or a complete graph (other than K4 or K8). This corresponds to the result of Fan [J. Combin. Theory Ser. B 74 (1998) 353-367] that every graph without cut-edges has a cycle cover of total size at most e+n-1.  相似文献   

17.
Suppose thatG is an undirected graph whose edges have nonnegative integer-valued lengthsl(e), and that {s 1,t 1},?, {s m ,t m } are pairs of its vertices. Can one assign nonnegative weights to the cuts ofG such that, for each edgee, the total weight of cuts containinge does not exceedl(e) and, for eachi, the total weight of cuts ‘separating’s i andt i is equal to the distance (with respect tol) betweens i andt i ? Using linear programming duality, it follows from Papernov's multicommodity flow theorem that the answer is affirmative if the graph induced by the pairs {s 1,t 1},?, {s m ,t m } is one of the following: (i) the complete graph with four vertices, (ii) the circuit with five vertices, (iii) a union of two stars. We prove that if, in addition, each circuit inG has an even length (with respect tol) then there exists a suitable weighting of the cuts with the weights integer-valued; moreover, an algorithm of complexity O(n 3) (n is the number of vertices ofG) is developed for solving such a problem. Also a class of metrics decomposable into a nonnegative linear combination of cut-metrics is described, and it is shown that the separation problem for cut cones isNP-hard.  相似文献   

18.
The main result of this paper is an n-dimensional version of the Steinhaus' chessboard theorem. Our theorem implies the Poincaré theorem as well as its parametric extension. But it is known that the Poincaré theorem is equivalent to the Brouwer Fixed-Point theorem.  相似文献   

19.
In this paper we establish an existence of solution theorem and an existence of bifurcation point theorem for Hammerstein integral equation whose kernel is supposed neither symmetric nor positive defined. To prove our result, we use the Tychonoff fixed point theorem. In particular, our bifurcation result is directly comparable with an analogous one recently established by F. Faraci.  相似文献   

20.
The Desargues theorem is a basic theorem in classical projective geometry. In this paper we generalize Desargues theorem in the direction of dynamical systems. Our result comprises an infinite family of configurations, having unbounded complexity. The proof of the result involves constructing special kinds of hyperplane arrangements and then projecting subsets of them into the plane.  相似文献   

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