DSpace Community: 2006
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Corrigendum for "Weierstrass Points with first Non-Gap four on a Double Covering of a Hyperelliptic Curve"
http://hdl.handle.net/10525/2547
Title: Corrigendum for "Weierstrass Points with first Non-Gap four on a Double Covering of a Hyperelliptic Curve"<br/><br/>Authors: Komeda, Jiryo; Ohbuci, Akira<br/><br/>Abstract: In the proof of Lemma 3.1 in [1] we need to show that we may take the two points p and q with p ≠ q such thatp+q+(b-2)g21(C′)∼2(q1+… +qb-1)where q1,…,qb-1 are points of C′, but in the paper [1] we did not show that p ≠ q. Moreover, we hadn't been able to prove this using the method of our paper [1]. So we must add some more assumption to Lemma 3.1 and rewrite the statements of our paper after Lemma 3.1. The following is the correct version of Lemma 3.1 in [1] with its proof.Sun, 01 Jan 2006 00:00:00 GMTSubvarieties of the Hyperelliptic Moduli Determined by Group Actions
http://hdl.handle.net/10525/2540
Title: Subvarieties of the Hyperelliptic Moduli Determined by Group Actions<br/><br/>Authors: Shaska, T.<br/><br/>Abstract: Let Hg be the moduli space of genus g hyperelliptic curves. In this note, we study the locus Hg (G,σ) in Hg of curves admitting a G-action of given ramification type σ and inclusions between such loci. For each genus we determine the list of all possible groups, the inclusions among the loci, and the corresponding equations of the generic curve in Hg (G, σ). The proof of the results is based solely on representations of finite subgroups of PGL2 (C) and the Riemann-Hurwitz formula.<br/><br/>Description: 2000 Mathematics Subject Classification: 14Q05, 14Q15, 14R20, 14D22.Sun, 01 Jan 2006 00:00:00 GMTLarge and Moderate Deviations Principles for Recursive Kernel Estimator of a Multivariate Density and its Partial Derivatives
http://hdl.handle.net/10525/2539
Title: Large and Moderate Deviations Principles for Recursive Kernel Estimator of a Multivariate Density and its Partial Derivatives<br/><br/>Authors: Mokkadem, Abdelkader; Mariane, Pelletier; Baba, Thiam<br/><br/>Abstract: In this paper we prove large and moderate deviations principles for the recursive kernel estimator of a probability density function and its partial derivatives. Unlike the density estimator, the derivatives estimators exhibit a quadratic behaviour not only for the moderate deviations scale but also for the large deviations one. We provide results both for the pointwise and the uniform deviations.<br/><br/>Description: 2000 Mathematics Subject Classification: 62G07, 60F10.Sun, 01 Jan 2006 00:00:00 GMTA Characterization Theorem for the K-functional Associated with the Algebraic Version of Trigonometric Jackson Integrals
http://hdl.handle.net/10525/2538
Title: A Characterization Theorem for the K-functional Associated with the Algebraic Version of Trigonometric Jackson Integrals<br/><br/>Authors: Zapryanova, T.<br/><br/>Abstract: The purpose of this paper is to present a characterization of a certain Peetre K-functional in Lp[−1,1] norm, for 1 ≤ p ≤ 2 by means of a modulus of smoothness. This modulus is based on the classical one taken on a certain linear transform of the function.<br/><br/>Description: 2000 Mathematics Subject Classification: 41A25, 41A36.Sun, 01 Jan 2006 00:00:00 GMTOn Connection between Characterestic Functions and the Caratheodori Class Functions
http://hdl.handle.net/10525/2537
Title: On Connection between Characterestic Functions and the Caratheodori Class Functions<br/><br/>Authors: Zolotarev, Vladimir A.; Hatamleh, Raéd<br/><br/>Abstract: Connection of characteristic functions S(z) of nonunitary operator T with the functions of Caratheodori class is established. It was demonstrated that the representing measures from integral representation of the function of Caratheodori's class are defined by restrictions of spectral measures of unitary dilation, of a restricted operator T on the corresponding defect subspaces.<br/><br/>Description: 2000 Mathematics Subject Classification: 47A65, 45S78.Sun, 01 Jan 2006 00:00:00 GMTWeakly Compact Generating and Shrinking Markusevic Bases
http://hdl.handle.net/10525/2536
Title: Weakly Compact Generating and Shrinking Markusevic Bases<br/><br/>Authors: Fabian, M.; Hájek, P.; Montesinos, V.; Zizler, V.<br/><br/>Abstract: It is shown that most of the well known classes of nonseparable Banach spaces related to the weakly compact generating can be characterized by elementary properties of the closure of the coefficient space of Markusevic bases for such spaces. In some cases, such property is then shared by all Markusevic bases in the space.<br/><br/>Description: 2000 Mathematics Subject Classification: 46B30, 46B03.Sun, 01 Jan 2006 00:00:00 GMTCayley-Hamilton Theorem for Matrices over an Arbitrary Ring
http://hdl.handle.net/10525/2534
Title: Cayley-Hamilton Theorem for Matrices over an Arbitrary Ring<br/><br/>Authors: Szigeti, Jeno<br/><br/>Abstract: For an n×n matrix A over an arbitrary unitary ring R, we obtain the following Cayley-Hamilton identity with right matrix coefficients:(λ0I+C0)+A(λ1I+C1)+… +An-1(λn-1I+Cn-1)+An (n!I+Cn) = 0,where λ0+λ1x+…+λn-1 xn-1+n!xn is the right characteristic polynomial of A in R[x], I ∈ Mn(R) is the identity matrix and the entries of the n×n matrices Ci, 0 ≤ i ≤ n are in [R,R]. If R is commutative, then C0 = C1 = … = Cn-1 = Cn = 0 and our identity gives the n! times scalar multiple of the classical Cayley-Hamilton identity for A.<br/><br/>Description: 2000 Mathematics Subject Classification: 15A15, 15A24, 15A33, 16S50.Sun, 01 Jan 2006 00:00:00 GMTFinite Groups as the Union of Proper Subgroups
http://hdl.handle.net/10525/2533
Title: Finite Groups as the Union of Proper Subgroups<br/><br/>Authors: Zhang, Jiping<br/><br/>Abstract: As is known, if a finite solvable group G is an n-sum group then n − 1 is a prime power. It is an interesting problem in group theory to study for which numbers n with n-1 > 1 and not a prime power there exists a finite n-sum group. In this paper we mainly study finite nonsolvable n-sum groups and show that 15 is the first such number. More precisely, we prove that there exist no finite 11-sum or 13-sum groups and there is indeed a finite 15-sum group. Results by J. H. E. Cohn and M. J. Tomkinson are thus extended and further generalizations are possible.<br/><br/>Description: 2000 Mathematics Subject Classification: 20D60,20E15.Sun, 01 Jan 2006 00:00:00 GMTKadec Norms on Spaces of Continuous Functions
http://hdl.handle.net/10525/2530
Title: Kadec Norms on Spaces of Continuous Functions<br/><br/>Authors: Burke, Maxim R.; Wiesaw, Kubis; Stevo, Todorcevic<br/><br/>Abstract: We study the existence of pointwise Kadec renormings for Banach spaces of the form C(K). We show in particular that such a renorming exists when K is any product of compact linearly ordered spaces, extending the result for a single factor due to Haydon, Jayne, Namioka and Rogers. We show that if C(K1) has a pointwise Kadec renorming and K2 belongs to the class of spaces obtained by closing the class of compact metrizable spaces under inverse limits of transfinite continuous sequences of retractions, then C(K1×K2) has a pointwise Kadec renorming. We also prove a version of the three-space property for such renormings.<br/><br/>Description: 2000 Mathematics Subject Classification: Primary: 46B03, 46B26. Secondary: 46E15, 54C35.Sun, 01 Jan 2006 00:00:00 GMTMultipliers on Spaces of Functions on a Locally Compact Abelian Group with Values in a Hilbert Space
http://hdl.handle.net/10525/2527
Title: Multipliers on Spaces of Functions on a Locally Compact Abelian Group with Values in a Hilbert Space<br/><br/>Authors: Petkova, Violeta<br/><br/>Abstract: We prove a representation theorem for bounded operators commuting with translations on L2ω(G,H), where G is a locally compact abelian group, H is a Hilbert space and ω is a weight on G. Moreover, in the particular case when G = R, we characterize completely the spectrum of the shift operator S1,ω on Lω2(R,H).<br/><br/>Description: 2000 Mathematics Subject Classification: Primary 43A22, 43A25.Sun, 01 Jan 2006 00:00:00 GMTOn the Residuum of Concave Univalent Functions
http://hdl.handle.net/10525/2523
Title: On the Residuum of Concave Univalent Functions<br/><br/>Authors: Wirths, K.-J.<br/><br/>Abstract: Let D denote the open unit disc and f:D→[`C] be meromorphic and injective in D. We further assume that f has a simple pole at the point p О (0,1) and is normalized by f(0) = 0 and f′(0) = 1. In particular, we are concerned with f that map D onto a domain whose complement with respect to [`C] is convex. Because of the shape of f(D) these functions will be called concave univalent functions with pole p and the family of these functions is denoted by Co(p).We determine for fixed p ∈ (0,1) the set of variability of the residuum of f, f ∈ Co(p).<br/><br/>Description: 2000 Mathematics Subject Classification: 30C25, 30C45.Sun, 01 Jan 2006 00:00:00 GMTSome generalization of Desargues and Veronese configurations
http://hdl.handle.net/10525/2520
Title: Some generalization of Desargues and Veronese configurations<br/><br/>Authors: Prazmowska, Malgorzata; Krzysztof, Prazmowski<br/><br/>Abstract: We propose a method of constructing partial Steiner triple system, which generalizes the representation of the Desargues configuration as a suitable completion of three Veblen configurations. Some classification of the resulting configurations is given and the automorphism groups of configurations of several types are determined.<br/><br/>Description: 2000 Mathematics Subject Classification: 51E14, 51E30.Sun, 01 Jan 2006 00:00:00 GMTHausdorff Measures of Noncompactness and Interpolation Spaces
http://hdl.handle.net/10525/2519
Title: Hausdorff Measures of Noncompactness and Interpolation Spaces<br/><br/>Authors: da Silva, Eduardo Brandani; Fernanadez, Dicesar L.<br/><br/>Abstract: A new measure of noncompactness on Banach spaces is defined from the Hausdorff measure of noncompactness, giving a quantitative version of a classical result by R. S. Phillips. From the main result, classical results are obtained now as corollaries and we have an application to interpolation theory of Banach spaces.<br/><br/>Description: 2000 Mathematics Subject Classification: 46B50, 46B70, 46G12.Sun, 01 Jan 2006 00:00:00 GMTModuli stacks of polarized K3 surfaces in mixed characteristic
http://hdl.handle.net/10525/2517
Title: Moduli stacks of polarized K3 surfaces in mixed characteristic<br/><br/>Authors: Rizov, Jordan<br/><br/>Abstract: In this note we define moduli stacks of (primitively) polarized K3 spaces. We show that they are representable by Deligne-Mumford stacks over Spec(Z). Further, we look at K3 spaces with a level structure. Our main result is that the moduli functors of K3 spaces with a primitive polarization of degree 2d and a level structure are representable by smooth algebraic spaces over open parts of Spec(Z). To do this we use ideas of Grothendieck, Deligne, Mumford, Artin and others.These results are the starting point for the theory of complex multiplication for K3 surfaces and the definition of Kuga-Satake abelian varieties in positive characteristic given in our Ph.D. [J. Rizov. Moduli of K3 Surfaces and Abelian Variaties. Ph. D. thesis, University of Utrecht, 2005]. thesis.<br/><br/>Description: 2000 Mathematics Subject Classification: 14J28, 14D22.Sun, 01 Jan 2006 00:00:00 GMTLp extremal polynomials. Results and perspectives
http://hdl.handle.net/10525/2514
Title: Lp extremal polynomials. Results and perspectives<br/><br/>Authors: Laskri, Yamina; Benzine, Rachid<br/><br/>Abstract: Let α = β+γ be a positive finite measure defined on the Borel sets of C, with compact support, where β is a measure concentrated on a closed Jordan curve or on an arc (a circle or a segment) and γ is a discrete measure concentrated on an infinite number of points.In this survey paper, we present a synthesis on the asymptotic behaviour of orthogonal polynomials or Lp extremal polynomials associated to the measure α. We analyze some open problems and discuss new ideas related to their solving.<br/><br/>Description: 2000 Mathematics Subject Classification: 30C40, 30D50, 30E10, 30E15, 42C05.Sun, 01 Jan 2006 00:00:00 GMTAn extension of Lorentz's almost convergence and applications in Banach spaces
http://hdl.handle.net/10525/2509
Title: An extension of Lorentz's almost convergence and applications in Banach spaces<br/><br/>Authors: Mercourakis, S.; Vassiliadis, G.<br/><br/>Abstract: We investigate an extension of the almost convergence of G. G. Lorentz requiring that the means of a bounded sequence converge uniformly on a subset M of N. We also present examples of sequences α∈ l∞(N) whose sequences of translates (Tn α)n≥ 0 (where T is the left-shift operator on l∞(N)) satisfy: (a) Tn α, n ≥ 0 generates a subspace E(α) of l∞(N) that is isomorphically embedded into c0 while α is not almost convergent. (b) Tn α, n ≥ 0 admits an l1-subsequence and a nontrivial weakly Cauchy subsequence while a is almost convergent. Finally we show that, in the sense of measure, for almost all real sequences taking values in a compact set K ⊆ R (with at least two points), the sequence (Tn α)n ≥ 0 is equivalent in the supremum norm to the usual l1-basis and (hence) not almost convergent.<br/><br/>Description: 2000 Mathematics Subject Classification: Primary 40C99, 46B99.Sun, 01 Jan 2006 00:00:00 GMT