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 Using elementary graded automorphisms of polytopal algebras (essentially the coordinate rings of projective toric varieties) polyhedral versions of the group of elementary matrices and the Steinberg and Milnor groups are defined. They coincide with the usual K-theoretic groups in the special case when the polytope is a unit simplex and can be thought of as compact/polytopal substitutes for the tame automorphism groups of polynomial algebras. Relative to the classical case, many new aspects have to be taken into account. We describe these groups explicitly when the underlying polytope is 2-dimensional. Already this low-dimensional case provides interesting classes of groups. Received: 13 December 2001 / Revised version: 24 June 2002 The second author was supported by the Deutsche Forschungsgemeinschaft, INTAS grant 99-00817 and TMR grant ERB FMRX CT-97-0107 Mathematics Subject Classification (2000): 14L27, 14M25, 19C09, 52B20  相似文献   

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In this paper, we show, among other results, that if X is a [separable] locally compact space X [satisfying the first countability axiom] then the space Cc (X) has countable tightness [if and only if it has bounding tightness] if and only if it is Frechet-Urysohn, if and only if Cc (X) contains a dense (LM) subspace and if and only if X is a-compact.  相似文献   

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For estimating the entropy of an absolutely continuous multivariate distribution, we propose nonparametric estimators based on the Euclidean distances between the n sample points and their k n -nearest neighbors, where {k n : n = 1, 2, …} is a sequence of positive integers varying with n. The proposed estimators are shown to be asymptotically unbiased and consistent.   相似文献   

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The concepts of K-large and generalized K-large Abelian groups are introduced, and their main properties and interconnections are studied. We consider groups that are K-large (generalized K-large) with respect to the class of all groups and torsion-free groups. The main focus is on the case where K consists of bounded p-groups for an infinite set of prime numbers p. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 13, No. 3, pp. 51–60, 2007.  相似文献   

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We obtain a new inequality for weakly (K1,K2)-quasiregular mappings by using the McShane extension method. This inequality can be used to derive the self-improving regularity of (K1, K2)-Quasiregular Mappings.  相似文献   

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We introduce a resonance method to produce large values of the Riemann zeta-function on the critical line, and large and small central values of L-functions. The author is partially supported by the National Science Foundation (DMS 0500711) and the American Institute of Mathematics (AIM).  相似文献   

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 We give a characterization of strongly compact cardinals in terms of Q κ λ. We also prove that weakly normal Q-measures on Q κ λ are ⊂κ-normal. Received: 29 September 2000 / Revised version: March 2002 Published online: 5 November 2002 This project is supported by the New Zealand Marsden Fund. The author wishes to thank the referee for numerous comments and suggestions which have been incorporated into this version of the paper.  相似文献   

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Summary In [6] we introduced and investigated the notions of fI -sets and fI -continuous functions in ideal topological spaces. In this paper, we investigate their further important properties.  相似文献   

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The definition of lacunary strongly convergence is extended to the definition of lacunary strong (A σ , p)-convergence with respect to invariant mean when A is an infinite matrix and p = (p i ) is a strictly positive sequence. We study some properties and inclusion relations.  相似文献   

11.
The hyperoperations, called theta-operations (δ), are motivated from the usual property, which the derivative has on the derivation of a product of functions. Using any map on a set, one can define δ-operations. In this paper, we continue our study on the δ-operations on groupoids, rings, fields and vector spaces or on the corresponding hyperstructures. Using δ-operations one obtains, mainly, Hwstructures, which form the largest class of the hyperstructures. For representation theory of hyperstructures, by hypermatrices, one needs special Hv-rings or Hy-fields, so these hyperstructures can be used. Moreover, we study the relation of these δ-structures with other classes of hyperstructures, especially with the Hv-structures.  相似文献   

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Surfaces in Euclidean three-space with constant ratio of mean curvature to Gauss curvature arise naturally as the parallel surfaces to minimal surfaces. They might possess singularities which occur naturally as focal points of minimal surfaces. We study geometric properties and the singularities of such surfaces, prove some global results about them, and provide a Björling formula to construct such surfaces with prescribed point or curve singularities.  相似文献   

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We consider some problems concerning the L p,q -cohomology of Riemannian manifolds. In the first part, we study the question of the normal solvability of the operator of exterior derivation on a surface of revolution M considered as an unbounded linear operator acting from Lpk (M) into Lk+1q (M). In the second part, we prove that the first L p,q-cohomology of the general Heisenberg group is nontrivial, provided that p < q. Received: 17 January 2006 Supported by INTAS (Grant 03–51–3251) and the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grants NSh 311.2003.1, NSh 8526.2006.1).  相似文献   

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In this note we study the relation between k R -spaces and k-spaces and prove that a k R -space with a σ-hereditarily closure-preserving k-network consisting of compact subsets is a k-space, and that a k R -space with a point-countable k-network consisting of compact subsets need not be a k-space. This work was supported by the NSF of China (10271056).  相似文献   

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The aim of this paper is to define the localization LM n -algebra of an LM n —algebra L with respect to a topology F on L; in Section 5 we prove that the maximal LM n -algebra of fractions (defined in [3]) and the LM n -algebra of fractions relative to an Λ—closed system (defined in Section 2) are LM n -algebras of localization.  相似文献   

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In this paper we construct a simply connected, minimal, complex surface of general type with p g =0 and K 2=2 using a rational blow-down surgery and a ℚ-Gorenstein smoothing theory. Mathematics Subject Classification (2000) Primary 14J29; Secondary 14J10, 14J17, 53D05  相似文献   

20.
In this paper, we introduce Pexiderized generalized operators on certain special spaces introduced by Bielecki-Czerwik and investigate their norms.  相似文献   

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