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We give a purely algebro-geometric proof of the fact that every nonsingular
projective curve can be defined over a finite extension of its moduli field.
This extends a result byWolfart [7] to curves over fields of arbitrary
characteristic.
Received: 30 November 2001 相似文献
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In 1987 the Canadian Department of National Defence enunciated the Total Force concept. The Total Force is comprised of Regular and Reserve components. The intention is to make maximum use of the Reserve to reduce defence expenditures and at the same time to ensure that military capability remains adequate to support national policy objectives. This paper discusses some of the governing parameters that affect the modelling of the composition of the Total Force and analyses the mix of regular and reserve forces. The interplay between the key factors and their marginal costs will be stressed. The models are employed to study two units in the Canadian Forces, a maintenance support unit and a tactical unit with high operational activity cost. The lessons drawn from these studies are highlighted. 相似文献
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We say that a vertexx of a graph is predominant if there exists another vertexy ofG such that either every maximum clique ofG containingy containsx or every maximum stable set containingx containsy. A graph is then called preperfect if every induced subgraph has a predominant vertex. We show that preperfect graphs are perfect, and that several well-known classes of perfect graphs are preperfect. We also derive a new characterization of perfect graphs. 相似文献
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Time and spatially resolved absorption measurements of Xe* particle number densities performed at an X-ray preionized self-sustained XeCl*-laser discharge were used to investigate the reaction kinetics of such discharges and to test the validity of the commonly-made assumption that they are fit well by spatially homogeneous numerical models. It turned out that the Xe* density distribution over the discharge cross section remains homogeneous for less than 100 ns only. Comparing the experimental results of the homogeneous discharge phase with zero-dimensional model calculations, we conclude that induced emission modeled using two excited xenon levels must be taken into account for the quantitative interpretation of the absorption measurements. For the interpretation of the Xe 6s-6p absorption measurements even a multilevel model will be necessary. Further we conclude from the relative courses and the absolute values of the Xe* particle number densities that realistic HCl kinetics should contain three vibrationally excited levels and stepwise excitation processes as proposed by Dem'yanov et al. [8]. 相似文献
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Zusammenfassung Die Darstellung sämtlicher am mittleren Benzolkern p-substitutierten Verbindungen (C6H5)2
MC6H4
M(C6H5)2 mitM=N, P, As, Sb und Bi wird beschrieben. Für die bereits bekannte Stickstoff-bzw. Arsen-Verbindung konnte ein neuer Darstellungs-weg mit guten Ausbeuten gefunden werden, während die Antimon-und Wismutverbindung erstmals beschrieben werden. Durch Dipolmomentmessungen, UV- und IR-Aufnahmen ist ein Vergleich mit den einfachen Triphenylderivaten der genannten Elemente möglich.
Herrn Prof. Dr.F. Wessely zum 70. Geburtstag gewidmet. 相似文献
The compounds p-(C6H5)2 MC6H4 M(C6H5)2,M=N, P, As, Sb, and Bi, were prepared. New methods for the preparation of the N and As compound with good yields were found. The Sb and Bi compound were synthesized for the first time. Dipole moments, IR- and UV-spectra of these compounds were compared with those of the triphenyl derivates.
Herrn Prof. Dr.F. Wessely zum 70. Geburtstag gewidmet. 相似文献
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