Graph-theoretic conditions for injectivity of functions on rectangular domains

This paper presents sufficient graph-theoretic conditions for injectivity of collections of differentiable functions on rectangular subsets of R^n. The results have implications for the possibility of multiple fixed points of maps and flows. Well-known results on systems with signed Jacobians are shown to be easy corollaries of more general results presented here.Comment: 16 pages, 5 figure

Polynomial Rings and Topological Strings

An overview is given of the construction of a differential polynomial ring of functions on the moduli space of Calabi-Yau threefolds. These rings coincide with the rings of quasi modular forms for geometries with duality groups for which these are known. They provide a generalization thereof otherwise. Higher genus topological string amplitudes can be expressed in terms of the generators of this ring giving them a global description in the moduli space. An action of a duality exchanging large volume and conifold loci in moduli space is discussed. The connection to quasi modular forms is illustrated by the local P^2 geometry and its mirror, the generalization is extended to several compact geometries with one-dimensional moduli spaces.Comment: 10 pages, 2 figures, contribution to the proceedings of the String-Math 2013 conferenc

Spacecraft contamination programs within the Air Force Systems Command Laboratories

Spacecraft contamination programs exist in five independent AFSC organizations: Geophysics Laboratory (GL), Arnold Engineering and Development Center (AEDC), Rome Air Development Center (RADC/OSCE), Wright Research and Development Center (MLBT), Armament Laboratory (ATL/SAI), and Space Systems Division (SSD/OL-AW). In addition, a sizable program exists at Aerospace Corp. These programs are complementary, each effort addressing a specific area of expertise: GL's effort is aimed at addressing the effects of on-orbit contamination; AEDC's effort is aimed at ground simulation and measurement of optical contamination; RADC's effort addresses the accumulation, measurement, and removal of contamination on large optics; MLBT's effort is aimed at understanding the effect of contamination on materials; ATL's effort is aimed at understanding the effect of plume contamination on systems; SSD's effort is confined to the integration of some contamination experiments sponsored by SSD/CLT; and Aerospace Corp.'s effort is aimed at supporting the needs of the using System Program Offices (SPO) in specific areas, such as contamination during ground handling, ascent phase, laboratory measurements aimed at understanding on-orbit contamination, and mass loss and mass gain in on-orbit operations. These programs are described in some detail, with emphasis on GL's program

The trends of labor market in Bangladesh and its determinants

In this paper, we have tried to find out specially the features of unemployment-underemployment scenario. As we know, like auction market labor market is not perfectly competitive. For various heterogeneities, it has some distinct features. In Bangladesh, unemployment and underemployment problems arrive due to the lack of effective demand for labor. Hence, in this paper we desire to focus the demand determinants of labor in Bangladesh. In this case, we have emphasized on manufacturing sector, which is the emerging sector of Bangladesh economy both from the employment generation and from economic growth perspectives. To estimate the demand determinants we have used ARDL model where the estimation period is from 1980 to 2002

Global convergence in systems of differential equations arising from chemical reaction networks

It is shown that certain classes of differential equations arising from the modelling of chemical reaction networks have the following property: the state space is foliated by invariant subspaces each of which contains a unique equilibrium which, in turn, attracts all initial conditions on the associated subspace.Comment: Some typos and minor errors from the previous version have been correcte