45,071 research outputs found

    Property Tax and Urban Sprawl: Theory and Implications for U.S. Cities

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    This article attempts a formal analysis of the connection between property tax and urban sprawl in U.S. cities. We develop a theoretical model that includes households (who are also landlords) and land developers in a regional land market. We then test the model empirically based on a national sample of urbanized areas. The results we obtained from both theoretical and empirical analyses indicate that increasing property tax rates reduces the size of urbanized areas.Urban Sprawl; Full Closed City; Urban Economics; Property Tax; Instrumental Variables

    (0,4)(0, 4) dualities

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    We study a class of two-dimensional N=(0,4){\cal N}=(0, 4) quiver gauge theories that flow to superconformal field theories. We find dualities for the superconformal field theories similar to the 4d N=2{\cal N}=2 theories of class S{\cal S}, labelled by a Riemann surface C{\cal C}. The dual descriptions arise from various pair-of-pants decompositions, that involves an analog of the TNT_N theory. Especially, we find the superconformal index of such theories can be written in terms of a topological field theory on C{\cal C}. We interpret this class of SCFTs as the ones coming from compactifying 6d N=(2,0){\cal N}=(2, 0) theory on CP1×C\mathbb{CP}^1 \times {\cal C}Comment: 41 pages, 12 figure

    Learning Deep Representations of Appearance and Motion for Anomalous Event Detection

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    We present a novel unsupervised deep learning framework for anomalous event detection in complex video scenes. While most existing works merely use hand-crafted appearance and motion features, we propose Appearance and Motion DeepNet (AMDN) which utilizes deep neural networks to automatically learn feature representations. To exploit the complementary information of both appearance and motion patterns, we introduce a novel double fusion framework, combining both the benefits of traditional early fusion and late fusion strategies. Specifically, stacked denoising autoencoders are proposed to separately learn both appearance and motion features as well as a joint representation (early fusion). Based on the learned representations, multiple one-class SVM models are used to predict the anomaly scores of each input, which are then integrated with a late fusion strategy for final anomaly detection. We evaluate the proposed method on two publicly available video surveillance datasets, showing competitive performance with respect to state of the art approaches.Comment: Oral paper in BMVC 201

    Vertex operator algebras of Argyres-Douglas theories from M5-branes

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    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 JJ on a punctured sphere. We denote the AD theories as (Jb[k],Y)(J^b[k],Y), where Jb[k]J^b[k] and YY represent an irregular and a regular singularity respectively. We restrict to the `minimal' case where Jb[k]J^b[k] 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 Wk2d(J,Y)\mathcal{W}^{k_{2d}}(J,Y), where k2d=−h+bb+kk_{2d}=-h+ \frac{b}{b+k} with hh being the dual Coxeter number of JJ. 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 b=hb=h. 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
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