9,799 research outputs found
Natural curvature for manifest T-duality
We reformulate the manifestly T-dual description of the massless sector of
the closed bosonic string, directly from the geometry associated with the (left
and right) affine Lie algebra of the coset space Poincare/Lorentz. This
construction initially doubles not only the (spacetime) coordinates for
translations but also those for Lorentz transformations (and their dual). As a
result, the Lorentz connection couples directly to the string (as does the
vielbein), rather than being introduced ad hoc to the covariant derivative as
previously. This not only reproduces the old definition of T-dual torsion, but
automatically gives a general, covariant definition of T-dual curvature (but
still with some undetermined connections).Comment: Minor changes in notations (see e.g. eq.(7), eq.(8)). Some typos
corrected: e.g factor "i" in equations (11) and (12). New references adde
T-duality off shell in 3D Type II superspace
We give the manifestly T-dual formulation of the massless sector of the
classical 3D Type II superstring in off-shell 3D N=2 superspace, including the
action. It has a simple relation to the known superspace of 4D N=1 supergravity
in 4D M-theory via 5D F-theory. The pre potential appears as part of the
vielbein, without derivatives.Comment: References added, factor of 2 in the algebra (8) fixe
Employment at Will: Just Cause Protection Through Mandatory Arbitration
Employees\u27 primary interest in wrongful termination litigation is job security. Job security has many meanings. It may imply a tenure system with discharge for exceptional circumstances only. On the other hand, it may refer to a limited training and transfer system for reassigning displaced employees. The question is what type of security the average employee needs. Employers, by contrast, are primarily interested in management freedom. Restricting management\u27s freedom to terminate employees affects the employer by increasing costs and reducing productivity. Productivity is reduced when management retains incompetent or unnecessary employees for fear of litigation. Costs are increased through both litigation and remedial costs. Moreover, society has an interest in minimizing, to the extent possible, the costs of resolving wrongful termination disputes. When balancing these interests, two questions arise: What restrictions, if any, should be placed on an employer\u27s right to determine its workforce, and what forum, judicial or administrative, is appropriate to enforce these limitations? Courts and commentators generally agree that an employer should not have unfettered discretion to terminate an employee. Indeed, in forty-one states, courts have adopted some restriction governing the discharge of employees. By contrast, the question of the appropriate enforcement mechanism remains unresolved, and is, therefore, the focus of this Comment. For both theoretical and practical reasons, a judicial approach to wrongful termination is inappropriate. Instead, a statutory guarantee of termination only for cause, coupled with an administrative system of enforcement, can better balance the competing concerns. Such a scheme would benefit both employers and employees. Finally, Washington should adopt such an administrative system
Costly banknote issuance and interest rates under the national banking system
The behavior of interest rates under the U.S. National Banking System is puzzling because of the apparent presence of persistent and large unexploited arbitrage opportunities for note issuing banks. Previous attempts to explain interest rate behavior have relied on the cost or the inelasticity of note issue. These attempts are not entirely satisfactory. Here we propose a new rationale to solve the puzzle. Inelastic note issuance arises endogenously because the marginal cost of issuing notes is an increasing function of circulation. We build a spatial separation model where some fraction of agents must move each period. Banknotes can be carried between locations; deposits cannot. Taking the model to the data on national banks, we find it matches the movements in long-term interest rates well. It also predicts movements in deposit rates during panics. However, the model displays more inelasticity of notes issuance than is in the data.Bank notes ; Interest rates ; National banks (United States)
Towards a directed homotopy type theory
In this paper, we present a directed homotopy type theory for reasoning
synthetically about (higher) categories, directed homotopy theory, and its
applications to concurrency. We specify a new `homomorphism' type former for
Martin-L\"of type theory which is roughly analogous to the identity type former
originally introduced by Martin-L\"of. The homomorphism type former is meant to
capture the notions of morphism (from the theory of categories) and directed
path (from directed homotopy theory) just as the identity type former is known
to capture the notions of isomorphism (from the theory of groupoids) and path
(from homotopy theory). Our main result is an interpretation of these
homomorphism types into Cat, the category of small categories. There, the
interpretation of each homomorphism type hom(a,b) is indeed the set of
morphisms between the objects a and b of a category C. We end the paper with an
analysis of the interpretation in Cat with which we argue that our homomorphism
types are indeed the directed version of Martin-L\"of's identity types
A feasibility study: Forest Fire Advanced System Technology (FFAST)
The National Aeronautics and Space Administration/Jet Propulsion Laboratory and the United States Department of Agriculture Forest Service completed a feasibility study that examined the potential uses of advanced technology in forest fires mapping and detection. The current and future (1990's) information needs in forest fire management were determined through interviews. Analysis shows that integrated information gathering and processing is needed. The emerging technologies that were surveyed and identified as possible candidates for use in an end to end system include ""push broom'' sensor arrays, automatic georeferencing, satellite communication links, near real or real time image processing, and data integration. Matching the user requirements and the technologies yielded a ""strawman'' system configuration. The feasibility study recommends and outlines the implementation of the next phase for this project, a two year, conceptual design phase to define a system that warrants continued development
The St. Eustace legend as palimpsest in Hoban’s Riddley Walker
The St. Eustace Legend as Palimpsest in Hoban\u27s Riddley Walker. In Riddley Walker (1980), Russell Hoban uses the medieval legend of St. Eustace as the basis for his fictional society. Used to project a folklore, a system of belief, for a future world, the legend (and its additions by Hoban) acts as a palimpsest, a text of many layers. It explains the origins and present circumstances of Riddley Walker\u27s society, acts as a chemical formula providing the ironic renewal of technological capabilities, and illuminates the narrator\u27s personal story. The legend of St. Eustace was one of the most popular stories of the Middle Ages. Originally known as Placidus and a captain of the Emperor Trajan, the future saint was out hunting when he saw a white stag between whose horns appeared a bright light that formed a cross on which was the figure of Christ. The Christ figure spoke: Placidus, I am Christ whom you have hitherto served without knowing me. Do you not believe? Placidus answered, Lord, I believe. The vision then told him that he would suffer many tribulations, but that the Lord would not forsake him. Placidus, his wife, and two sons were baptized and Placidus took the new name Eustace
Hypertext: A Sacred (He)Art?: Cor ad Cor Loquitur from Augustine to Shelley Jackson.
Self-discovery, self-exploration, the creation of the self or the Subject is a human preoccupation that goes beyond the postmodern era. The epigraphs that begin this paper show that the human concern with how language and representation play a crucial role in the formation of the subject flows back through time from our present to Augustine, the fourth-century master of the art of self-knowledge, and beyond. When Augustine started writing his Confessions, the self as something to write about, a theme or object (subject) of writing activity, was already well established. In his Confessions, Augustine uses cor ad cor loquitur, or to put it plainly, having a heart to heart with God. Such a conversation was meant to change his life by teaching him how to revise himself in Christ\u27s image. In other words, cor ad cor loquitur is a lesson in subjectivity.
Today, as someone who is a medievalist, theologian, and techno-geek, I find myself pondering how this ancient and never-ending conversation echoes still, even in the realm of hypertext. And yes! I did say hypertext. As theologian and medievalist, I wander on my pilgrim way in many different worlds, antique and contemporary. For me, the hypertext world of Cyberia (that computerized technological world in to which we are presently evolving) continues the ancient trail of a conversation, of heart speaking to heart, in which subjectivity evolves. The mechanism of self-reflection, central to cor ad cor loquitur, resides in the rhetorical structure of hypertext. Contemporary pilgrims negotiating their way as author and audience through the lexias[i] and byways of Cyberia\u27s hypertext find themselves following in the footsteps of their medieval ancestors who pondered on author and audience in the book of the heart known as cor ad cor loquitur. I invite you to accompany me as I use the medievalist’s lens to investigate how hypertext is the latest evolution in cor ad cor loquitur
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