4,287 research outputs found

    A Linear First-Order Functional Intermediate Language for Verified Compilers

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    We present the linear first-order intermediate language IL for verified compilers. IL is a functional language with calls to a nondeterministic environment. We give IL terms a second, imperative semantic interpretation and obtain a register transfer language. For the imperative interpretation we establish a notion of live variables. Based on live variables, we formulate a decidable property called coherence ensuring that the functional and the imperative interpretation of a term coincide. We formulate a register assignment algorithm for IL and prove its correctness. The algorithm translates a functional IL program into an equivalent imperative IL program. Correctness follows from the fact that the algorithm reaches a coherent program after consistently renaming local variables. We prove that the maximal number of live variables in the initial program bounds the number of different variables in the final coherent program. The entire development is formalized in Coq.Comment: Addressed comments from reviewers (ITP 2015): (1) Added discussion of a paper in related work (2) Added definition of renamed-apart in appendix (3) Formulation changes in a coupe of place

    Recursive Method for the Density of States in One Dimension

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    We derive a powerful yet simple method for analyzing the local density of states in gapless one dimensional fermionic systems, including extensions such as momentum dependent interaction parameters and hard-wall boundaries. We study the crossover of the local DOS from individual density waves to the well-known asymptotic powerlaws and identify characteristic signs of spin charge separation in possible STM experiments. For semi-infinite systems a closed analytic expression is found in terms of hypergeometric functions.Comment: 5 pages and 3 figures. The latest version can be found at http://www.physik.uni-kl.de/eggert/papers/index.htm

    Dispersive analysis of omega --> 3pi and phi --> 3pi decays

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    We study the three-pion decays of the lightest isoscalar vector mesons, omega and phi, in a dispersive framework that allows for a consistent description of final-state interactions between all three pions. Our results are solely dependent on the phenomenological input for the pion-pion P-wave scattering phase shift. We predict the Dalitz plot distributions for both decays and compare our findings to recent measurements of the phi --> 3pi Dalitz plot by the KLOE and CMD-2 collaborations. Dalitz plot parameters for future precision measurements of omega --> 3pi are predicted. We also calculate the pi-pi P-wave inelasticity contribution from omega-pi intermediate states.Comment: 23 pages, 18 figures; discussion extended, Appendix D added, matches version published in EPJ

    Documentation IZAΨMOD: The IZA Policy SImulation MODel

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    This paper describes IZAΨMOD, the policy microsimulation model of the Institute for the Study of Labor (IZA). The model uses household microdata from the German Socio-Economic Panel Study and firm data from the German linked employer-employee dataset LIAB. IZAΨMOD consists of three components: First, a static module simulates the effects of a tax reform on the budget of the individual households. Secondly, behavioral labor supply responses are estimated. The third component distinguishes our model from most other microsimulation tools. A demand module takes into account possible restrictions of labor demand and identifies the partial equilibrium of the labor market after the supply reactions.IZAΨMOD, microsimulation, tax and benefit systems, labor demand
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