819 research outputs found

    A General Framework for Sound and Complete Floyd-Hoare Logics

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    This paper presents an abstraction of Hoare logic to traced symmetric monoidal categories, a very general framework for the theory of systems. Our abstraction is based on a traced monoidal functor from an arbitrary traced monoidal category into the category of pre-orders and monotone relations. We give several examples of how our theory generalises usual Hoare logics (partial correctness of while programs, partial correctness of pointer programs), and provide some case studies on how it can be used to develop new Hoare logics (run-time analysis of while programs and stream circuits).Comment: 27 page

    Semantics and Proof Theory of the Epsilon Calculus

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    The epsilon operator is a term-forming operator which replaces quantifiers in ordinary predicate logic. The application of this undervalued formalism has been hampered by the absence of well-behaved proof systems on the one hand, and accessible presentations of its theory on the other. One significant early result for the original axiomatic proof system for the epsilon-calculus is the first epsilon theorem, for which a proof is sketched. The system itself is discussed, also relative to possible semantic interpretations. The problems facing the development of proof-theoretically well-behaved systems are outlined.Comment: arXiv admin note: substantial text overlap with arXiv:1411.362

    From nonlinear to linearized elasticity via Γ-convergence: the case of multiwell energies satisfying weak coercivity conditions

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    Linearized elasticity models are derived, via Γ-convergence, from suitably rescaled non- linear energies when the corresponding energy densities have a multiwell structure and satisfy a weak coercivity condition, in the sense that the typical quadratic bound from below is replaced by a weaker p bound, 1 < p < 2, away from the wells. This study is motivated by, and our results are applied to, energies arising in the modeling of nematic elastomers

    Calculation of the work function with a local basis set

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    Electronic structure codes usually allow to calculate the work function as a part of the theoretical description of surfaces and processes such as adsorption thereon. This requires a proper calculation of the electrostatic potential in all regions of space, which is apparently straightforward to achieve with plane wave basis sets, but more difficult with local basis sets. To overcome this, a relatively simple scheme is proposed to accurately compute the work function when a local basis set is used, by having some additional basis functions in the vacuum. Tests on various surfaces demonstrate that a very good agreement with experimental and other theoretical data can be achieved.Comment: to appear in Surf. Sci. Let

    On entanglement evolution across defects in critical chains

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    We consider a local quench where two free-fermion half-chains are coupled via a defect. We show that the logarithmic increase of the entanglement entropy is governed by the same effective central charge which appears in the ground-state properties and which is known exactly. For unequal initial filling of the half-chains, we determine the linear increase of the entanglement entropy.Comment: 11 pages, 5 figures, minor changes, reference adde

    Lacticacidaemia due to pyruvate dehydrogenase deficiency, with evidence of protein polymorphism in the α-subunit of the enzyme

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    In three infants with neonatal lacticacidaemia, a deficiency in the E 1 (pyruvate dehydrogenase) component of the pyruvate dehydrogenase complex was demonstrated in skin fibroblast cultures. Residual activites of the pyruvate dehydrogenase complex in the activated state were 1.6%, 3.9% and 18.8% of control values, respectively. Immunoprecipitation of extracts of cultures skin fibroblasts grown on 35 S-methionine with anti-pyruvate dehydrogenase complex antibody revealed an abnormality in the E 1 α-component of these three patients when visualised after sodium dodecyl sulphate/polyacrylamide gel electrophoresis. This component appeared to have a slightly lower molecular weight than did this protein from control cell strains. Cell strains from other patients with a deficiency of the pyruvate dehydrogenase complex did not exhibit this defect. Three patients also showed dysmorphism and developmental abnormalities of the central nervous system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47532/1/431_2004_Article_BF00441736.pd

    Explicit Evidence Systems with Common Knowledge

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    Justification logics are epistemic logics that explicitly include justifications for the agents' knowledge. We develop a multi-agent justification logic with evidence terms for individual agents as well as for common knowledge. We define a Kripke-style semantics that is similar to Fitting's semantics for the Logic of Proofs LP. We show the soundness, completeness, and finite model property of our multi-agent justification logic with respect to this Kripke-style semantics. We demonstrate that our logic is a conservative extension of Yavorskaya's minimal bimodal explicit evidence logic, which is a two-agent version of LP. We discuss the relationship of our logic to the multi-agent modal logic S4 with common knowledge. Finally, we give a brief analysis of the coordinated attack problem in the newly developed language of our logic

    A Review of CAM for Procedural Pain in Infancy: Part I. Sucrose and Non-nutritive Sucking

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    There is increasing concern regarding the number of painful medical procedures that infants must undergo and the potential risks of alleviating infant pain with conventional pharmacologic agents. This article is Part I of a two-part series that aims to provide an overview of the literature on complementary and alternative (CAM) approaches for pain and distress related to medical procedures among infants up to six weeks of age. The focus of this article is a review of the empirical literature on sucrose with or without non-nutritive sucking (NNS) for procedural pain in infancy. Computerized databases were searched for relevant studies including prior reviews and primary trials. The most robust evidence was found for the analgesic effects of sucrose with or without NNS on minor procedural pain in healthy full-term infants. Despite some methodological weaknesses, the literature to date supports the use of sucrose, NNS and other sweetened solutions for the management of procedural pain in infancy
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