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In this paper,we completely classify 3-dimensional complete self-shrinkers with the constant norm S of the second fundamental form and the constant f3 in the Euclidean space R4,where hij’s are components of the second fundamental form,S=∑i,j hij2 and f3=∑i,j,k hijhjkhki.  相似文献   

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Embeddings of graphs into ℝ3 such that each line contains minimal possible number of points of the image are considered. It is proved that for every embedding into ℝ3 of a graph containing the disjoint union of two Kuratowski-Pontryagin graphs there exists a line containing four points of the image or more. Therefore, disjoint unions of Kuratowski-Pontryagin graphs are minimal 3-nonembeddable graphs.  相似文献   

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We prove that for each normed space Y of infinite dimension and each porous set E ? ? there exists a Lipschitz mapping f: ? → Y such that the graph of f has a tangent at each of its points and f is not differentiable at any point of E. In this article we continue our research in [1] on contingents.  相似文献   

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It is well-known that the Shannon entropies of some parameterized probability distributions are concave functions with respect to the parameter. In this paper we consider a family of such distributions (including the binomial, Poisson, and negative binomial distributions) and investigate their Shannon, Rényi, and Tsallis entropies with respect to complete monotonicity.  相似文献   

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We study foliations of space forms by complete hypersurfaces, under some mild conditions on its higher order mean curvatures. In particular, in Euclidean space we obtain a Bernstein-type theorem for graphs whose mean and scalar curvature do not change sign but may otherwise be nonconstant. We also establish the nonexistence of foliations of the standard sphere whose leaves are complete and have constant scalar curvature, thus extending a theorem of Barbosa, Kenmotsu and Oshikiri. For the more general case of r-minimal foliations of the Euclidean space, possibly with a singular set, we are able to invoke a theorem of Ferus to give conditions under which the non- singular leaves are foliated by hyperplanes.  相似文献   

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We consider complete ideals supported on finite sequences of infinitely near points, in regular local rings with dimensions greater than two. We study properties of factorizations in Lipman special *-simple complete ideals. We relate it to a type of proximity, linear proximity, of the points, and give conditions in order to have unique factorization. Several examples are presented. Received: 2 February 2000 / in final form: 14 March 2001 / Published online: 18 January 2002  相似文献   

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欧拉Gamma函数是一种非常重要的函数,在数学的许多分支以及物理、工程等学科中都有着十分重要的作用.而完全单调性以及对数完全单调性是Gamma函数的重要性质.主要证明了一些包含Gamma函数和Psi函数在内的特殊函数的完全单调性和对数完全单调性,并由此推出了一些重要的不等式.  相似文献   

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We continue studying the associative rings complete and reduced in the sense of Martynov. We prove that the group of invertible elements of a reduced associative ring is reduced. We compute the complete radical of a group ring over the ring of integers and the complete radical of the group algebra over an arbitrary algebra over a finite prime field.  相似文献   

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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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A decomposition of a complete graph into disjoint copies of a complete bipartite graph is called a ‐design of order n. The existence problem of ‐designs has been completely solved for the graphs for , for , K2, 3 and K3, 3. In this paper, I prove that for all , if there exists a ‐design of order N, then there exists a ‐design of order n for all (mod ) and . Giving necessary direct constructions, I provide an almost complete solution for the existence problem for complete bipartite graphs with fewer than 18 edges, leaving five orders in total unsolved.  相似文献   

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We construct new examples of embedded, complete, minimal hypersurfaces in complex hyperbolic space, including deformations of bisectors and some minimal foliations. Received: 20 March 2000 / Revised version: 21 July 2000  相似文献   

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We construct new examples of embedded, complete minimal hypersurfaces in quaternionic hyperbolic space and also some minimal foliations. We introduce fans and construct analytic deformations of bisectors.  相似文献   

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We study the extremals of a functional I(l) with the boundary conditions x(0) = y(0) = z(0) = 0, x(1) = a, y(1) = b, and z(1) = c.  相似文献   

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This paper gives a classification of complete hypersurfaces with nonzero constant mean curvature and constant quasi-Gauss-Kronecker curvature in the hyperbolic space H4(-1),whose scalar curvature is bounded from below.  相似文献   

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