2,390 research outputs found

    Spacing properties of the zeros of orthogonal polynomials on Cantor sets via a sequence of polynomial mappings

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    Let μ\mu be a probability measure with an infinite compact support on R\mathbb{R}. Let us further assume that (Fn)n=1(F_n)_{n=1}^\infty is a sequence of orthogonal polynomials for μ\mu where (fn)n=1(f_n)_{n=1}^\infty is a sequence of nonlinear polynomials and Fn:=fnf1F_n:=f_n\circ\dots\circ f_1 for all nNn\in\mathbb{N}. We prove that if there is an s0Ns_0\in\mathbb{N} such that 00 is a root of fnf_n^\prime for each n>s0n>s_0 then the distance between any two zeros of an orthogonal polynomial for μ\mu of a given degree greater than 11 has a lower bound in terms of the distance between the set of critical points and the set of zeros of some FkF_k. Using this, we find sharp bounds from below and above for the infimum of distances between the consecutive zeros of orthogonal polynomials for singular continuous measures.Comment: Contains less typo

    National project for the evaluation of ERTS imagery applications to various earth resources problems of Turkey

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    There are no author-identified significant results in this report

    Orthogonal polynomials on generalized Julia sets

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    We extend results by Barnsley et al. about orthogonal polynomials on Julia sets to the case of generalized Julia sets. The equilibrium measure is considered. In addition, we discuss optimal smoothness of Green functions and Parreau-Widom criterion for a special family of real generalized Julia sets.Comment: We changed the second part of the article a little bit and gave sharper results in this versio

    Contribution of two diagnosis tools to support interface situation during production launch

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    Organised by: Cranfield UniversityFirms are urged to constantly introduce new products. Hence, the New Product Development process should be mastered, especially its final phase, the production launch. This paper addresses the critical issue of the information exchange during production launch. Two diagnosis tools considering production launch as a key interface are presented. They permit to examine the information flows, to highlight their weaknesses and hence to find solutions for further improvements. This paper also presents the results of a case study where the diagnosis tools were implemented during a switchgear development project.Mori Seiki – The Machine Tool Compan

    Non-perturbative effects of vacuum energy on the recent expansion of the universe

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    We show that the vacuum energy of a free quantized field of very low mass can significantly alter the recent expansion of the universe. The effective action of the theory is obtained from a non-perturbative sum of scalar curvature terms in the propagator. We numerically investigate the semiclassical Einstein equations derived from it. As a result of non-perturbative quantum effects, the scalar curvature of the matter-dominated universe stops decreasing and approaches a constant value. The universe in our model evolves from an open matter-dominated epoch to a mildly inflating de Sitter expansion. The Hubble constant during the present de Sitter epoch, as well as the time at which the transition occurs from matter-dominated to de Sitter expansion, are determined by the mass of the field and by the present matter density. The model provides a theoretical explanation of the observed recent acceleration of the universe, and gives a good fit to data from high-redshift Type Ia supernovae, with a mass of about 10^{-33} eV, and a current ratio of matter density to critical density, Omega_0 <0.4 . The age of the universe then follows with no further free parameters in the theory, and turns out to be greater than 13 Gyr. The model is spatially open and consistent with the possibility of inflation in the very early universe. Furthermore, our model arises from the standard renormalizable theory of a free quantum field in curved spacetime, and does not require a cosmological constant or the associated fine-tuning.Comment: 30 pages, 4 figures, revtex; references added; minor revisions in Sec

    Orthogonal polynomials for the weakly equilibrium Cantor sets

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    Let K(γ)K(\gamma) be the weakly equilibrium Cantor type set introduced in [10]. It is proven that the monic orthogonal polynomials Q2sQ_{2^s} with respect to the equilibrium measure of K(γ)K(\gamma) coincide with the Chebyshev polynomials of the set. Procedures are suggested to find QnQ_{n} of all degrees and the corresponding Jacobi parameters. It is shown that the sequence of the Widom factors is bounded below
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