共查询到19条相似文献,搜索用时 140 毫秒
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多复变数星形映照的两类子族 总被引:3,自引:0,他引:3
本文首先讨论有界星形圆型域上星形映照的一个子族---次星形映照,着重研究其几何性质,包括增长定理与掩盖定理.然后,在有界凸圆型域上讨论星形映照的另一类子族---α次的γ-凸映照.讨论它与星形映照,β次星形映照以及凸映照的关系. 相似文献
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基于星形集空间的性质,定义一类星形可微函数.这类函数是方向可微的,其方向导数可以表示成两个正齐次非负连续函数之差,其星形微分为一星形集对.对于含有不等式约束条件的星形可微优化问题,给出一个Fritz-John形式的最优性必要条件. 相似文献
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本文首先讨论有界星形圆型域上星形映照的一个子族-α次星形映照,着重研究其几何性质,包括增长定理与掩盖定理然后,在有界凸圆型域上讨论星形映照的另一类子族-α次的γ-凸映照,讨论它与星形映照,β次星形映照以及凸映照的关系 相似文献
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本文研究了推广的Roper-Suffridge算子保持一些双全纯映照子族的性质.利用一些双全纯映照子族的定义,得到了推广后的Roper-Suffridge算子在复Banach空间单位球上保持ρ次抛物形β型螺形映照及强α次殆星形映照的性质,由此得到复Hilbert空间上推广的Roper-Suffridge算子的相应性质,推广了已有的结论. 相似文献
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本文刻划了周期为p的稳定平移箭图Z△/(τp)的邻接矩阵,并给出了由星形箭图△所决定的平移箭图Z△/(τp)的邻接矩阵的具体形式. 相似文献
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本文将Cn中的Roper-Suffridge算子推广到任意复Banach空间中,并证明这种算子在任意复Banach空间中的某些区域上具有保持ε星形性,由此可以构造出任意复Banach空间,复Hilbert空间和Cn中的一些区域上的许多双全纯星形映照、双全纯凸映照、双全纯ε星形映照,同时,得到它们的增长定理等,将龚升与刘太顺,Roper与suffridge,Graham,Kohr等学者在Cn中的一些结果推广到任意复Banach空间或复Hilbert空间中. 相似文献
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本文分别讨论Cn中某一Reinhardt域上以及复Hilbert空间单位球上推广的Roper-Suffridge算子保持α(-π/2<α<π/2)型螺形性和保持α(0<α<1)次星形性.所得结果包含了已知对应的结论. 相似文献
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凸性与度量投影的连续性 总被引:9,自引:0,他引:9
本文研究近强凸、近非常凸Banach空间中度量投影的连续性。获得如下结果:若A是近强凸(近非常凸)空间中的逼近凸集,则度量投影PA是范-范上半连续的(范-弱上半连续的)。此外,我们还利用度量投影的连续性给出Banach空间为近强凸、近非常凸的一些充分必要条件。 相似文献
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D. Goeleven 《Journal of Global Optimization》1996,9(2):121-140
The hemivariational inequality approach is used in order to establish the existence of solutions to a large class of noncoercive constrained problems in a reflexive Banach space, in which the set of all admissible elements is not convex but fulfills some star-shaped property.Chargé de Recherches du Fonds National Belge de la Recherche Scientifique. 相似文献
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关于度量投影的连续性 总被引:10,自引:1,他引:9
本文引入的Banach空间的(C-I)、(C-Ⅱ),(C-Ⅲ)等几何性质,证明了如下结果。设M是Banach空间的逼近凸子集,如果Banach空间有性质(C-I),(C-Ⅱ)(C-Ⅲ),则度量投影PM连续(范数-范数上半连续,范数-弱上半连续)。这些结果推广了文(4,7,8)相应的定理。最近,D.Kutzarova,Bor-Luh Lin等引入了一些新的凸性空间,本文还研究了这些凸性空间中度量投影 相似文献
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A straight-line planar drawing of a plane graph is called a convex drawing if every facial cycle is drawn as a convex polygon. Convex drawings of graphs is a well-established aesthetic in graph drawing, however not all planar graphs admit a convex drawing. Tutte [W.T. Tutte, Convex representations of graphs, Proc. of London Math. Soc. 10 (3) (1960) 304–320] showed that every triconnected plane graph admits a convex drawing for any given boundary drawn as a convex polygon. Thomassen [C. Thomassen, Plane representations of graphs, in: Progress in Graph Theory, Academic Press, 1984, pp. 43–69] gave a necessary and sufficient condition for a biconnected plane graph with a prescribed convex boundary to have a convex drawing.In this paper, we initiate a new notion of star-shaped drawing of a plane graph as a straight-line planar drawing such that each inner facial cycle is drawn as a star-shaped polygon, and the outer facial cycle is drawn as a convex polygon. A star-shaped drawing is a natural extension of a convex drawing, and a new aesthetic criteria for drawing planar graphs in a convex way as much as possible. We give a sufficient condition for a given set A of corners of a plane graph to admit a star-shaped drawing whose concave corners are given by the corners in A, and present a linear time algorithm for constructing such a star-shaped drawing. 相似文献
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N. A. Bobylev 《Mathematical Notes》1999,65(4):430-435
Questions related to the properties of unions and intersections of star-shaped compact subsets of finite-dimensional spaces
are considered.
Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 511–519, April, 1999. 相似文献
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讨论了赋范空间中度量投影的收敛性.得到了在局部紧集控制下,Chebyshev凸集序列的度量投影的收敛性与K-M收敛,Wijsman收敛和Kuratowski收敛都等价.本文的结论完善了M.Tsukada在[1]和[2]结果. 相似文献
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In this paper, we first give a simple proof of the decomposition theorem in Alber (Field Inst. Comm. 25 (2000) 77) and then present a new decomposition of arbitrary elements in reflexive strictly convex and smooth Banach spaces. As applications of the decomposition theorem, we give the representations of the metric projection operator for some kind of closed convex sets. Finally, we provide a sufficient condition under which the generalized projection operator coincides with the metric projection operator. 相似文献
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以Banach空间的一般凸集为研究对象,将Banach空间的凸性研究推广到了内部非空的凸集上.打破了从单位球出发研究Banach空间几何的具有局限性的研究方法,给出了严格凸集的若干特征刻画及性质,并得到了严格凸集和光滑集之间的对偶定理. 相似文献