3,164 research outputs found
Rota-Baxter operators on Witt and Virasoro algebras
The homogeneous Rota-Baxter operators on the Witt and Virasoro algebras are
classified. As applications, the induced solutions of the classical Yang-Baxter
equation and the induced pre-Lie and PostLie algebra structures are obtained.Comment: 28 page
CSD: Discriminance with Conic Section for Improving Reverse k Nearest Neighbors Queries
The reverse nearest neighbor (RNN) query finds all points that have
the query point as one of their nearest neighbors (NN), where the NN
query finds the closest points to its query point. Based on the
characteristics of conic section, we propose a discriminance, named CSD (Conic
Section Discriminance), to determine points whether belong to the RNN set
without issuing any queries with non-constant computational complexity. By
using CSD, we also implement an efficient RNN algorithm CSD-RNN with a
computational complexity at . The comparative
experiments are conducted between CSD-RNN and other two state-of-the-art
RkNN algorithms, SLICE and VR-RNN. The experimental results indicate that
the efficiency of CSD-RNN is significantly higher than its competitors
Quantum Hall Effects in a Non-Abelian Honeycomb Lattice
We study the tunable quantum Hall effects in a non-Abelian honeycomb optical
lattice which is a many-Dirac-points system. We find that the quantum Hall
effects present different features as change as relative strengths of several
perturbations. Namely, a gauge-field-dressed next-nearest-neighbor hopping can
induce the quantum spin Hall effect and a Zeeman field can induce a so-called
quantum anomalous valley Hall effect which includes two copies of quantum Hall
states with opposite Chern numbers and counter-propagating edge states. Our
study extends the borders of the field of quantum Hall effects in honeycomb
optical lattice when the internal valley degrees of freedom enlarge.Comment: 7 pages, 6 figure
Kinematic properties of the dual AGN system J0038+4128 based on long-slit spectroscopy
The study of kiloparsec-scale dual active galactic nuclei (AGN) will provide
important clues to understand the co-evolution between the host galaxies and
their central supermassive black holes undergoing a merging process. We present
long-slit spectroscopy of the J00384128, a kiloparsec-scale dual AGN
candidate discovered by Huang et al. recently, using the Yunnan Faint Object
Spectrograph and Camera (YFOSC) mounted on Li-Jiang 2.4-m telescope at Yunnan
observatories. From the long-slit spectra, we find that the average relative
line-of-sight (LOS) velocity between the two nuclei (J00384128N and
J00384128S) is about 150 km s. The LOS velocities of the emission
lines from the gas ionized by the nuclei activities and of the absorption lines
from stars governed by the host galaxies for different regions of the
J00384128 exhibit the same trend. The same velocities trend indicates that
the gaseous disks are co-rotating with the stellar disks in this ongoing merge
system. We also find several knots/giant HII regions scattered around the two
nuclei with strong star formation revealed by the observed line ratios from the
spectra. Those regions are also detected clearly in HST -band and HST
-band images.Comment: 12 pages, 5 figures, 3 tables, Research in Astronomy and Astrophysics
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