Systematic proof of the existence of Yangian symmetry in chiral Gross-Neveu models

The existence of non-local charges, generating a Yangian symmetry is discussed in generalized chiral Gross-Neveu models. Their conservation can be proven by a finite-loop perturbative computation, the order of which is determined from group theoretic constants and is independent of the number of flavors. Examples, where the 1-loop calculation is sufficient, include the SO(n)-models and other more exotic groups and representations.Comment: 12 pages, LaTe

College Campus Sexual Assault and Retention Rates

Increased media attention on college crime, specifically sexual assault, has led to greater prioritization of campus safety when deciding whether to continue attending a college. This, coupled with society’s view of a four-year college education as a necessity to succeed in the labor market, creates a potential tradeoff between safety on campus and future employment success. To analyze such tradeoff, I use data from the US Department of Education from 2014 to 2017 to examine whether college campus sexual assault at four-year American institutions impacts retention rates. Such results have implications for college policies to combat sexual assault on campus not only to keep students safe, but to prevent students from transferring or dropping out which could curb institutional money flow. Using an OLS model that addresses typical difficulties associated with time series work, I find that college campus sexual assault decreases retention rates at a statistically significant level, implying that college students value their safety at school more than any potential change in their future job market success due to transferring or dropping out

College Crime and Retention Rates

Increased media attention on college crime has led to greater prioritization of campus safety when selecting a college to attend. This, coupled with society’s view of higher education as a necessity to succeed in the labor market, creates a potential tradeoff between safety on campus and future job success. To analyze such tradeoff, I examine whether college crime affects retention rates at four-year American institutions. While literature has focused on college crime and factors that affect the decision to begin attending a college, no study has solely focused on the college crime and the decision to continue attending a college. Using data from the US Department of Education, I estimate the effect of college crime and changing college crime expectations on retention rates from 2009 to 2016 for four-year institutions using linear and nonlinear OLS regressions. Such results have implications for college policies to combat crime on campus not only to keep students safe, but to prevent students from transferring or dropping out. Using an instrumental regression with a proxy for average state temperature, along with fixed effects and interaction terms, I find that college crime expectations and college crime overall have a negative, statistically insignificant effect on retention rates

Del Pezzo Surfaces and Affine 7-brane Backgrounds

A map between string junctions in the affine 7-brane backgrounds and vector bundles on del Pezzo surfaces is constructed using mirror symmetry. It is shown that the lattice of string junctions with support on an affine 7-brane configuration is isomorphic to the K-theory group of the corresponding del Pezzo surface. This isomorphism allows us to construct a map between the states of the N=2, D=4 theories with E_N global symmetry realized in two different ways in Type IIB and Type IIA string theory. A subgroup of the SL(2,Z) symmetry of the \hat{E}_9 7-brane background appears as the Fourier-Mukai transform acting on the D-brane configurations realizing vector bundles on elliptically fibered B_9.Comment: 19 pages, LaTeX, 2 eps figures. v2: minor changes, version to appear in JHE

One Homonym per Translation

The study of homonymy is vital to resolving fundamental problems in lexical semantics. In this paper, we propose four hypotheses that characterize the unique behavior of homonyms in the context of translations, discourses, collocations, and sense clusters. We present a new annotated homonym resource that allows us to test our hypotheses on existing WSD resources. The results of the experiments provide strong empirical evidence for the hypotheses. This study represents a step towards a computational method for distinguishing between homonymy and polysemy, and constructing a definitive inventory of coarse-grained senses.Comment: 8 pages, including reference

D-branes in Nonabelian Orbifolds with Discrete Torsion

We study IIB string theory on the orbifold R^8/Gamma with discrete torsion where Gamma is an arbitrary subgroup of U(4). We extend some previously known identities for discrete torsion in abelian groups to nonabelian groups. We construct explicit formulas for a large class of fractional D-brane states and prove that the physical states are classified by projective representations of the orbifold group as predicted originally by Douglas. The boundary states are found to be linear combinations of Ishibashi states with the coefficients being characters of the projective representations.Comment: 21 pages LaTeX, one eps figur