Gauged WZW models and Non-abelian duality

We consider WZW models based on the non-semi-simple algebras that they were recently constructed as contractions of corresponding algebras for semi-simple groups. We give the explicit expression for the action of these models, as well as for a generalization of them, and discuss their general properties. Furthermore we consider gauged WZW models based on these non-semi-simple algebras and we show that there are equivalent to non-abelian duality transformations on WZW actions. We also show that a general non-abelian duality transformation can be thought of as a limiting case of the non-abelian quotient theory of the direct product of the original action and the WZW action for the symmetry gauge group $H$. In this action there is no Lagrange multiplier term that constrains the gauge field strength to vanish. A particular result is that the gauged WZW action for the coset $(G_k \otimes H_l)/H_{k+l}$ is equivalent, in the limit $l\to \infty$, to the dualized WZW action for $G_k$ with respect to the subgroup $H$.Comment: 35 pages, harvmac, THU-94/01 (a few minor changes in subsec. 4.1 are made, a 3rd App. and a Note are added

Torsion and Supersymmetry in Omega-background

We study the dimensional reduction of ten-dimensional super Yang-Mills theory in curved backgrounds with torsion. We examine the parallel spinor conditions and the constraints for the torsion parameters which preserve supersymmetry and gauge symmetry in four dimensions. In particular we examine the ten-dimensional Omega-background with the torsion which is identified with the R-symmetry Wilson line gauge fields. After the dimensional reduction, we obtain the Omega-deformed N=4 super Yang-Mills theory. Solving the parallel spinor conditions and the torsion constraints, we classify the deformed supersymmetry associated with the topological twist of N=4 supersymmetry. We also study deformed supersymmetries in the Nekrasov-Shatashvili limit.Comment: 26 page

Perturbative renormalization of lattice N=4 super Yang-Mills theory

We consider N=4 super Yang-Mills theory on a four-dimensional lattice. The lattice formulation under consideration retains one exact supersymmetry at non-zero lattice spacing. We show that this feature combined with gauge invariance and the large point group symmetry of the lattice theory ensures that the only counterterms that appear at any order in perturbation theory correspond to renormalizations of existing terms in the bare lattice action. In particular we find that no mass terms are generated at any finite order of perturbation theory. We calculate these renormalizations by examining the fermion and auxiliary boson self energies at one loop and find that they all exhibit a common logarithmic divergence which can be absorbed by a single wavefunction renormalization. This finding implies that at one loop only a fine tuning of the finite parts is required to regain full supersymmetry in the continuum limit.Comment: v2. Minor corrections, references adde

Autonomous Vehicle Good Citizenry Standard

69A3551747119The supplemental files to this record include an "Autonomous Vehicle Literature Review," and an Executive Summary.To establish a framework for considering these wraparound AV impacts in New York City, the NYU Rudin Center for Transportation Policy and Management led a multi-stakeholder initiative in conjunction with NYU\u2019s C2SMART, USDOT University Transportation Center. The team hosted three workshops in December 2021 addressing issues and opportunities in seven topic areas: Local Governance, Community Outreach, Integration with Public Transit, Equity, Accessibility, Safety and Data Privacy. Participants represented the public and private sectors, advocacy and civic organizations, and academia. In addition, the research team conducted a quantitative study of equitable deployment of new mobility in New York City. The study finds that the ideal data aggregation level depends on the reliability of the public data collected for that community, and recommends a new tool to help design the appropriate data structure for data sharing. Based on this foundational research and stakeholder input, seven mobility policy principles are presented as a preliminary framework for approaching the wraparound policies concerning the introduction of autonomous vehicles to New York City: safety, serve all NYers equitably, engage NY's diverse communities, coexist with public transportation, intelligent interactions with the city, New York City\u2019s ongoing sustainability efforts, and public-private partnerships

Text Segmentation and Topic Tracking on Broadcast News via a Hidden Markov Model Approach

Continuing progress in the automatic transcription of broadcast speech via speech recognition has raised the possibility of applying information retrieval techniques to the resulting (errorful) text. In this paper we describe a general methodology based on Hidden Markov Models and classical language modeling techniques for automatically inferring story boundaries (segmentation) and for retrieving stories relating to a specific topic (tracking). We will present in detail the features and performance of the Segmentation and Tracking systems submitted by Dragon Systems for the 1998 Topic Detection and Tracking evaluation. 1. INTRODUCTION Over the last few years Dragon, like a number of other research sites, has been developing a speech recognition system capable of automatically transcribing broadcast speech. With the recent advances in this technology, a new source is becoming available for information mining, in the form of a continuous stream of errorful, unsegmented text. Applying s..