共查询到20条相似文献,搜索用时 31 毫秒
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In this note, we characterize finite three-dimensional affine spaces as the only linear spaces endowed with set Ω of proper subspaces having the properties (1) every line contains a constant number of points, say n, with n>2; (2) every triple of noncollinear points is contained in a unique member of Ω; (3) disjoint or coincide is an equivalence relation in Ω with the additional property that every equivalence class covers all points. We also take a look at the case n=2 (in which case we have a complete graph endowed with a set Ω of proper complete subgraphs) and classify these objects: besides the affine 3-space of order 2, two small additional examples turn up. Furthermore, we generalize our result in the case of dimension greater than three to obtain a characterization of all finite affine spaces of dimension at least 3 with lines of size at least 3. 相似文献
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《Journal of Functional Analysis》2023,284(1):109739
We give a sufficient (and, in the case of a compact domain, a necessary) condition for the embedding of Sobolev space of functions with integrable gradient into Besov-Orlicz spaces to be bounded. The condition has a form of a simple integral inequality involving Young and weight functions. We provide an example with Matuszewska-Orlicz indices of involved Orlicz norm equal to one. The main tool is the molecular decomposition of functions from a BV space. 相似文献
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Kyriakos Keremedis Eleftherios Tachtsis 《Proceedings of the American Mathematical Society》2007,135(4):1205-1211
We show that the existence of a countable, first countable, zero-dimensional, compact Hausdorff space which is not second countable, hence not metrizable, is consistent with ZF.
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Antonio S. Granero Henryk Hudzik 《Proceedings of the American Mathematical Society》1996,124(12):3777-3787
In this paper we study some structural and geometric properties of the quotient Banach spaces , where is an arbitrary set, is an Orlicz function, is the corresponding Orlicz space on and , being the ideal of elements with finite support. The results we obtain here extend and complete the ones obtained by Leonard and Whitfield (Rocky Mountain J. Math. 13 (1983), 531-539). We show that is not a dual space, that , if for every , that has no smooth points, that it cannot be renormed equivalently with a strictly convex or smooth norm, that is a Grothendieck space, etc.
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张静 《高校应用数学学报(A辑)》2017,32(1)
给出连通的rectifiable空间是局部序列连通(或局部连通)的刻画,推广了拓扑群中的相应结果;利用rectifiable空间G中e的局部邻域基给出G是局部连通(或局部序列连通)的刻画;证明了若A是rectifiable空间G中的序列开子集,那么H=A是G的序列开rectifiable子空间. 相似文献
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Joaquim Martín 《Journal of Mathematical Analysis and Applications》2008,344(1):99-123
We prove new extended forms of the Pólya-Szegö symmetrization principle in the fractional case. As a consequence we determine new results for rearrangement invariant hulls of generalized Besov spaces. 相似文献
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In this paper, we study the continuity and boundedness of linear operators defined between probabilistic modular spaces in
the probabilistic sense.
This research was in part supported by a grant from IPM (No. 86470033). 相似文献
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We show that (generalized) Calkin correspondence between quasi-normed symmetric sequence spaces and symmetrically quasi-normed ideals of compact operators on an infinite-dimensional Hilbert space preserves completeness. We also establish a semifinite version of this result. 相似文献
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We prove new extended forms of the Pólya-Szegö symmetrization principle. As a consequence new sharp embedding theorems for generalized Sobolev and Besov spaces are proved. 相似文献
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In this paper we identify some properties on the point-line structure of Grassmannians which are useful tools to characterize the incidence geometry of Grassmann varieties and of their special quotients. 相似文献
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本文研究单位圆盘上的BMOA空间和α-Bloch型空间之间的加权Cesáro算子,给出了T_g是BMOA空间到B_α空间的有界算子或紧算子的充分必要条件。 相似文献
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本文研究了一类次线性算子及其交换子在齐型空间上的弱有界性的问题.利用齐型空间的基本性质以及给出的一类次线性算子及其分别与BMO函数,Lipschitz函数生成的交换子在L~p(X)上的弱有界性,证明了其在齐型空间上Morrey-Herz空间中的弱有界性.推广了该类算子在Morrey-Herz空间中的强有界性这一结果. 相似文献
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Our main goal in this work is to further improve the mixed norm estimates due to Fournier [13], and also Algervik and Kolyada [1], to more general rearrangement invariant (r.i.) spaces. In particular we find the optimal domains and the optimal ranges for these embeddings between mixed norm spaces and r.i. spaces. 相似文献
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Joaquim Martí n Mario Milman 《Proceedings of the American Mathematical Society》2006,134(8):2335-2347
We prove new extended forms of the Pólya-Szegö symmetrization principle. As a consequence new sharp embedding theorems for generalized Besov spaces are proved, including a sharpening of the limiting cases of the classical Sobolev embedding theorem. In particular, a surprising self-improving property of certain Sobolev embeddings is uncovered.
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研究D-C chang等人引进的五个区域Hardy空间,刻划这些空间的原子分解和对偶空间,揭示了这些空间的内在联系。 相似文献
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Exploiting continuity properties of Fourier multipliers on modulation spaces and Wiener amalgam spaces, we study the Cauchy problem for the NLW equation. Local wellposedness for rough data in modulation spaces and Wiener amalgam spaces is shown. The results formulated in the framework of modulation spaces refine those in [A. Bényi, K.A. Okoudjou, Local well-posedness of nonlinear dispersive equations on modulation spaces, preprint, April 2007 (available at ArXiv:0704.0833v1)]. The same arguments may apply to obtain local wellposedness for the NLKG equation. 相似文献