共查询到20条相似文献,搜索用时 15 毫秒
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Krzysztof Plotka 《Proceedings of the American Mathematical Society》2003,131(4):1031-1041
We say that a function is a Hamel function ( ) if , considered as a subset of , is a Hamel basis for . We prove that every function from into can be represented as a pointwise sum of two Hamel functions. The latter is equivalent to the statement: for all there is a such that . We show that this fails for infinitely many functions.
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V. I. Diskant 《Journal of Mathematical Sciences》1990,48(1):41-49
A stability theorem is proved corresponding to this uniqueness theorem forn5,k3, and under the hypothesis that one of the projections of the convex body on a hyperplane ofR
n is a ball. In particular the stability theorem holds in the case when the body is a solid of revolution.Translated from Ukrainskií Geometricheskií Sbornik, Issue 28, 1985, pp. 50–62. 相似文献
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The infinitely differentiable real valued functions whose inverse have all the Taylor coefficients nonnegative at the fixed point of the axis are considered. An application to the theory of the inverse pair of the Radon measures is given. 相似文献
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Csaba D. Tth 《Computational Geometry》2000,17(3-4):121-134
It is shown that in any polygonal art gallery of n sides it is possible to place n/3 point guards whose range of vision is 180° so that every interior point of the gallery can be seen by at least one of them. The guards can be stationed at any point of the art gallery. This settles an open problem posed by J. Urrutia. 相似文献
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Let Ω⊂R
n
be an arbitrary open set. In this paper it is shown that if a Sobolev functionf∈W
1,p
(Ω) possesses a zero trace (in the sense of Lebesgue points) on ϖΩ, thenf is weakly zero on ϖΩ in the sense thatf∈W
0
1,p
(Ω). 相似文献
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In order to show that one can recapture the Riesz-Herglotz theorem from the Krein-Milman theorem, we determine directly the set of extreme points of the convex set of positive harmonic functions on the unit ball (normalized by 1 at the origin). The characterization is obtained using standard facts from abstract analysis combined with a minimum of very basic results on harmonic functions. 相似文献
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Analytic functions of a proper contraction 总被引:3,自引:0,他引:3
Ky Fan 《Mathematische Zeitschrift》1978,160(3):275-290
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Pandelis Dodos 《Journal of Functional Analysis》2011,260(5):1285-1303
Let X and Y be separable Banach spaces and T:X→Y be a bounded linear operator. We characterize the non-separability of T?(Y?) by means of fixing properties of the operator T. 相似文献
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Marie-Hélène Mourgues 《Archive for Mathematical Logic》2002,41(7):631-642
We extend the notion of absolute convergence for real series in several variables to a notion of convergence for series in
a power series field ℝ((t
Γ)) with coefficients in ℝ. Subsequently, we define a natural notion of analytic function at a point of ℝ((t
Γ))m. Then, given a real function f analytic on a open box I of ℝ
m
, we extend f to a function f
★ which is analytic on a subset of ℝ((t
Γ))
m
containing I. We prove that the functions f
★ share with real analytic functions certain basic properties: they are , they have usual Taylor development, they satisfy the inverse function theorem and the implicit function theorem.
Received: 5 October 2000 / Revised version: 19 June 2001 / Published online: 12 July 2002 相似文献
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