6,222 research outputs found
Property Tax in Urban China
This paper examines the urban housing sector of China and proposes a property tax reform. Over the past decade, housing price in urban China has been increasing dramatically because of strong demand for self-use, investment and speculation. The booming housing market, however, has brought several challenges for further development, such as housing affordability, inequality, and possible housing bubble. One strategy is to reform the current property tax system. Specifically, this paper proposes that China significantly reduces taxes in circulation but levies property tax during possession. Doing so will increase housing affordability because of lower transaction costs, reduce speculation because of higher cost of holding, stabilize fiscal system because of more sustainable tax revenues, and improve the efficiency and fairness of the property tax system because of the implementation of “ability-to-pay” and “who use who pay” principles.Property tax; China
Ethyl 5-chloromethyl-2-methylsulfanyl-7-phenyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxylate
In the title compound, C16H17ClN4O2S, the bicyclic triazolopyrimidine ring system is nearly planar and oriented with respect to the benzene ring at a dihedral angle of 87.24 (3)°. In the crystal structure, intermolecular N—H⋯N hydrogen bonds link the molecules into centrosymmetric dimers; an intramolecular C—H⋯O hydrogen bond is also present
Vertex operator algebras of Argyres-Douglas theories from M5-branes
We study aspects of the vertex operator algebra (VOA) corresponding to
Argyres-Douglas (AD) theories engineered using the 6d N=(2, 0) theory of type
on a punctured sphere. We denote the AD theories as , where
and represent an irregular and a regular singularity respectively.
We restrict to the `minimal' case where has no associated mass
parameters, and the theory does not admit any exactly marginal deformations.
The VOA corresponding to the AD theory is conjectured to be the W-algebra
, where with being
the dual Coxeter number of . We verify this conjecture by showing that the
Schur index of the AD theory is identical to the vacuum character of the
corresponding VOA, and the Hall-Littlewood index computes the Hilbert series of
the Higgs branch. We also find that the Schur and Hall-Littlewood index for the
AD theory can be written in a simple closed form for . We also test the
conjecture that the associated variety of such VOA is identical to the Higgs
branch. The M5-brane construction of these theories and the corresponding TQFT
structure of the index play a crucial role in our computations.Comment: 35 pages, 1 figure, v2: minor corrections, referenced adde
Automated Generation of Geometric Theorems from Images of Diagrams
We propose an approach to generate geometric theorems from electronic images
of diagrams automatically. The approach makes use of techniques of Hough
transform to recognize geometric objects and their labels and of numeric
verification to mine basic geometric relations. Candidate propositions are
generated from the retrieved information by using six strategies and geometric
theorems are obtained from the candidates via algebraic computation.
Experiments with a preliminary implementation illustrate the effectiveness and
efficiency of the proposed approach for generating nontrivial theorems from
images of diagrams. This work demonstrates the feasibility of automated
discovery of profound geometric knowledge from simple image data and has
potential applications in geometric knowledge management and education.Comment: 31 pages. Submitted to Annals of Mathematics and Artificial
Intelligence (special issue on Geometric Reasoning
Analysis of Problems in the Development of Online Teaching and Suggestions for Improvement
With the rapid development of information technology, various online learning platforms such as WeChat, MOOC, and Ding Talk are increasingly being used in classrooms, changing the way education is delivered. However, the adoption of online teaching has revealed some problems that have limited its effectiveness. The problems include insufficient network service capacity to support large-scale online learning, a lack of high-quality teaching resources, inadequate learning platform functions, and inadequate online learning habits among teachers and students. Although various means, such as Micro-Course Online Video, MOOC, intelligent teaching platforms, and artificial intelligence technologies can enrich the form of online education, online teaching has not yet maximized the use of information technology to improve education. This paper compares and analyzes online teaching and classroom teaching in terms of teaching resources, activities, evaluation, and outcomes, and proposes suggestions for improving online teaching, including improving network services, optimizing platform construction, promoting the reform of online teaching modes, deepening the integration of disciplines and information technology, and integrating online teaching into curriculum reform
Ethyl 2-benzylsulfanyl-7-(2-chlorophenyl)-5-methyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxylate
In the title compound, C22H21ClN4O2S, the bicyclic triazolopyrimidine ring system is nearly planar, and oriented at dihedral angles of 89.45 (3)° with respect to the chlorobenzene ring and 87.03 (3)° with respect to the terminal phenyl ring. In the crystal structure, molecules are linked by π–π stacking interactions between the triazolopyrimidine rings [centroid–centroid distances of 3.88 (1) and 3.63 (1) Å]
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