38,986 research outputs found

    On mutations of selfinjective quivers with potential

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    We study silting mutations (Okuyama-Rickard complexes) for selfinjective algebras given by quivers with potential (QPs). We show that silting mutation is compatible with QP mutation. As an application, we get a family of derived equivalences of Jacobian algebras.Comment: 19 pages, to appear in J. Pure Appl. Algebr

    Three-Dimensional Relativistic Magnetohydrodynamic Simulations of Current-Driven Instability with A Sub-Alfvenic Jet: Temporal Properties

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    We have investigated the influence of a velocity shear surface on the linear and non-linear development of the CD kink instability of force-free helical magnetic equilibria in 3D. In this study we follow the temporal development within a periodic computational box and concentrate on flows that are sub-Alfvenic on the cylindrical jet's axis. Displacement of the initial force-free helical magnetic field leads to the growth of CD kink instability. We find that helically distorted density structure propagates along the jet with speed and flow structure dependent on the radius of the velocity shear surface relative to the characteristic radius of the helically twisted force-free magnetic field. At small velocity shear surface radius the plasma flows through the kink with minimal kink propagation speed. The kink propagation speed increases as the velocity shear radius increases and the kink becomes more embedded in the plasma flow. A decreasing magnetic pitch profile and faster flow enhance the influence of velocity shear. Simulations show continuous transverse growth in the nonlinear phase of the instability. The growth rate of the CD kink instability and the nonlinear behavior also depend on the velocity shear surface radius and flow speed, and the magnetic pitch radial profile. Larger velocity shear radius leads to slower linear growth, makes a later transition to the nonlinear stage, and with larger maximum amplitude than occur for a static plasma column. However, when the velocity shear radius is much greater than the characteristic radius of the helical magnetic field, linear and non-linear development can be similar to the development of a static plasma column.Comment: 38 pages, 18 figures, accepted for publication in Ap

    The statistical relationship between product life cycle and repeat purchase behavior in convenience stores

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    The density function of product life cycles in convenience stores is found to follow the Weibull distribution. To clarify the parameters that determine these life cycles, we introduce the conditional market share-defined as the probability that a product is selected by customers only if it had been previously purchased-and the market share without any conditions. The product life cycle is more strongly correlated with the conditional market share of the product than with the latter type of market share.Comment: 9 pages, 5 figures, 3 tables. Progress of Theoretical Physics, in pres

    Inequality and Sequence of Economic Liberalization and Democratization

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    Some recent empirical studies found positive effects of economic liberalization on democratization. Based on these findings, this paper explains why the sequence of economic liberalization and democratization is related to the effects of the two reforms on economic performance. Since economic liberalization increases the probability of democratization and democratization leads to income redistribution, in an economy with large inequality between the elite and the poor, the elite do not implement economic liberalization, and democratization occurs first. In such an economy, the effects of economic liberalization and democratization are lower because of distortions caused by large-scale income redistribution.
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