3,722 research outputs found

    A Model of Interindustry Interaction in the USSR

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    A quantitative analysis of the development of interindustry flows in the Soviet economy showed that traditional input-output methods needed to be expanded and generalized for use in Soviet medium-term (5-7 year) planning. In particular, it is necessary to account for supply constraints on some products and relative surpluses of others. This paper describes a model which accounts for these influences, fits closely the development of the Soviet economy from 1950 to 1975, and can be and has been used in the exploratory stages of Soviet planning

    Fake News as a Parasit of Social Media

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    The article is devoted to the problem of fake news, which is understood as fabricated for the discrediting of some person or organization of the message, designed to spread viral in social media. Disinformation is now similar to a virus, easily clinging to the reader and undermining the reputation of both the object of the information attack and the distribution channel itself.Статья посвящена проблеме фейковых новостей, которые понимаются как сфабрикованные для дискредитации какой-то персоны или организации сообщения, рассчитанные на вирусное распространение в социальных сетях. Дезинформация становится похожа на вирус, легко цепляясь к читателю и подрывая репутацию как объекта информационной атаки, так и самого канала распространения новости

    Property (T)(T) for noncommutative universal lattices

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    We establish a new spectral criterion for Kazhdan's property (T)(T) which is applicable to a large class of discrete groups defined by generators and relations. As the main application, we prove property (T)(T) for the groups ELn(R)EL_n(R), where n3n\geq 3 and RR is an arbitrary finitely generated associative ring. We also strengthen some of the results on property (T)(T) for Kac-Moody groups from a paper of Dymara and Januszkiewicz (Invent. Math 150 (2002)).Comment: 47 pages; final versio

    Theory of transient spectroscopy of multiple quantum well structures

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    A theory of the transient spectroscopy of quantum well (QW) structures under a large applied bias is presented. An analytical model of the initial part of the transient current is proposed. The time constant of the transient current depends not only on the emission rate from the QWs, as is usually assumed, but also on the subsequent carrier transport across QWs. Numerical simulation was used to confirm the validity of the proposed model, and to study the transient current on a larger time scale. It is shown that the transient current is influenced by the nonuniform distribution of the electric field and related effects, which results in a step-like behavior of the current. A procedure of extraction of the QW emission time from the transient spectroscopy experiments is suggested.Comment: 5 pages, 4 figures, to be published in J. Appl. Phy

    Noiseless Collective Motion out of Noisy Chaos

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    We consider the effect of microscopic external noise on the collective motion of a globally coupled map in fully desynchronized states. Without the external noise a macroscopic variable shows high-dimensional chaos distinguishable from random motion. With the increase of external noise intensity, the collective motion is successively simplified. The number of effective degrees of freedom in the collective motion is found to decrease as logσ2-\log{\sigma^2} with the external noise variance σ2\sigma^2. It is shown how the microscopic noise can suppress the number of degrees of freedom at a macroscopic level.Comment: 9 pages RevTex file and 4 postscript figure

    Collective motions in globally coupled tent maps with stochastic updating

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    We study a generalization of globally coupled maps, where the elements are updated with probability pp. When pp is below a threshold pcp_c, the collective motion vanishes and the system is the stationary state in the large size limit. We present the linear stability analysis.Comment: 6 pages including 5 figure

    Monopoles, Dyons and Black Holes in the Four-Dimensional Einstein-Yang-Mills Theory

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    A continuum of monopole, dyon and black hole solutions exist in the Einstein-Yang-Mills theory in asymptotically anti-de Sitter space. Their structure is studied in detail. The solutions are classified by non-Abelian electric and magnetic charges and the ADM mass. The stability of the solutions which have no node in non-Abelian magnetic fields is established. There exist critical spacetime solutions which terminate at a finite radius, and have universal behavior. The moduli space of the solutions exhibits a fractal structure as the cosmological constant approaches zero.Comment: 36 Pages, 16 Figures. Minor typos corrected and one figure modifie

    Dyonic Non-Abelian Black Holes

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    We study static spherically symmetric dyonic black holes in Einstein-Yang-Mills-Higgs theory. As for the magnetic non-abelian black holes, the domain of existence of the dyonic non-abelian black holes is limited with respect to the horizon radius and the dimensionless coupling constant α\alpha, which is proportional to the ratio of vector meson mass and Planck mass. At a certain critical value of this coupling constant, α^\hat \alpha, the maximal horizon radius is attained. We derive analytically a relation between α^\hat \alpha and the charge of the black hole solutions and confirm this relation numerically. Besides the fundamental dyonic non-abelian black holes, we study radially excited dyonic non-abelian black holes and globally regular gravitating dyons.Comment: LaTeX, 22 pages, 16 figures, three figures added, file manipulation error in previous replac

    On the susceptibility function of piecewise expanding interval maps

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    We study the susceptibility function Psi(z) associated to the perturbation f_t=f+tX of a piecewise expanding interval map f. The analysis is based on a spectral description of transfer operators. It gives in particular sufficient conditions which guarantee that Psi(z) is holomorphic in a disc of larger than one. Although Psi(1) is the formal derivative of the SRB measure of f_t with respect to t, we present examples satisfying our conditions so that the SRB measure is not Lipschitz.*We propose a new version of Ruelle's conjectures.* In v2, we corrected a few minor mistakes and added Conjectures A-B and Remark 4.5. In v3, we corrected the perturbation (X(f(x)) instead of X(x)), in particular in the examples from Section 6. As a consequence, Psi(z) has a pole at z=1 for these examples.Comment: To appear Comm. Math. Phy
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