76,399 research outputs found
Self-organized model for information spread in financial markets
A self-organized model with social percolation process is proposed to
describe the propagations of information for different trading ways across a
social system and the automatic formation of various groups within market
traders. Based on the market structure of this model, some stylized
observations of real market can be reproduced, including the slow decay of
volatility correlations, and the fat tail distribution of price returns which
is found to cross over to an exponential-type asymptotic decay in different
dimensional systems.Comment: 8 pages with 7 EPS figures, LaTeX2e with EPJ class; Eur. Phys. J. B,
in pres
The global existence and convergence of the Calabi flow on
In this note, we study the long time existence of the Calabi flow on . Assuming the uniform bound of the
total energy, we establish the non-collapsing property of the Calabi flow by
using Donaldson's estimates and Streets' regularity theorem. Next we show that
the curvature is uniformly bounded along the Calabi flow on when the
dimension is 2, partially confirming Chen's conjecture. Moreover, we show that
the Calabi flow exponentially converges to the flat K\"ahler metric for
arbitrary dimension if the curvature is uniformly bounded, partially confirming
Donaldson's conjecture
The classification of two-loop integrand basis in pure four-dimension
In this paper, we have made the attempt to classify the integrand basis of
all two-loop diagrams in pure four-dimension space-time. Our classification
includes the topology of two-loop diagrams which determines the structure of
denominators, and the set of numerators under different kinematic
configurations of external momenta by using Gr\"{o}bner basis method. In our
study, the variety defined by setting all propagators to on-shell has played an
important role. We discuss the structure of variety and how it splits to
various irreducible branches when external momenta at each corner of diagrams
satisfy some special kinematic conditions. This information is crucial to the
numerical or analytical fitting of coefficients for integrand basis in
reduction process.Comment: 52 pages, 9 figures. v2 reference added, v3 published versio
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