39,752 research outputs found
On mutations of selfinjective quivers with potential
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
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
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
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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