1,158 research outputs found

    Relational semantics of linear logic and higher-order model-checking

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    In this article, we develop a new and somewhat unexpected connection between higher-order model-checking and linear logic. Our starting point is the observation that once embedded in the relational semantics of linear logic, the Church encoding of any higher-order recursion scheme (HORS) comes together with a dual Church encoding of an alternating tree automata (ATA) of the same signature. Moreover, the interaction between the relational interpretations of the HORS and of the ATA identifies the set of accepting states of the tree automaton against the infinite tree generated by the recursion scheme. We show how to extend this result to alternating parity automata (APT) by introducing a parametric version of the exponential modality of linear logic, capturing the formal properties of colors (or priorities) in higher-order model-checking. We show in particular how to reunderstand in this way the type-theoretic approach to higher-order model-checking developed by Kobayashi and Ong. We briefly explain in the end of the paper how his analysis driven by linear logic results in a new and purely semantic proof of decidability of the formulas of the monadic second-order logic for higher-order recursion schemes.Comment: 24 pages. Submitte

    A Fully Abstract Model for Mobile Ambients

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    AbstractAim of this paper is to investigate the possibility of developing filter models for calculi representing mobility. We will define a model for a variant of the Ambient Calculus. This model turns out to be fully abstract with respect to a notion of contextual equivalence which takes into account the ambients at top level

    Hybrid Session Verification through Endpoint API Generation

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    © Springer-Verlag Berlin Heidelberg 2016.This paper proposes a new hybrid session verification methodology for applying session types directly to mainstream languages, based on generating protocol-specific endpoint APIs from multiparty session types. The API generation promotes static type checking of the behavioural aspect of the source protocol by mapping the state space of an endpoint in the protocol to a family of channel types in the target language. This is supplemented by very light run-time checks in the generated API that enforce a linear usage discipline on instances of the channel types. The resulting hybrid verification guarantees the absence of protocol violation errors during the execution of the session. We implement our methodology for Java as an extension to the Scribble framework, and use it to specify and implement compliant clients and servers for real-world protocols such as HTTP and SMTP

    The Paths to Choreography Extraction

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    Choreographies are global descriptions of interactions among concurrent components, most notably used in the settings of verification (e.g., Multiparty Session Types) and synthesis of correct-by-construction software (Choreographic Programming). They require a top-down approach: programmers first write choreographies, and then use them to verify or synthesize their programs. However, most existing software does not come with choreographies yet, which prevents their application. To attack this problem, we propose a novel methodology (called choreography extraction) that, given a set of programs or protocol specifications, automatically constructs a choreography that describes their behavior. The key to our extraction is identifying a set of paths in a graph that represents the symbolic execution of the programs of interest. Our method improves on previous work in several directions: we can now deal with programs that are equipped with a state and internal computation capabilities; time complexity is dramatically better; we capture programs that are correct but not necessarily synchronizable, i.e., they work because they exploit asynchronous communication

    Call-by-value non-determinism in a linear logic type discipline

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    We consider the call-by-value lambda-calculus extended with a may-convergent non-deterministic choice and a must-convergent parallel composition. Inspired by recent works on the relational semantics of linear logic and non-idempotent intersection types, we endow this calculus with a type system based on the so-called Girard's second translation of intuitionistic logic into linear logic. We prove that a term is typable if and only if it is converging, and that its typing tree carries enough information to give a bound on the length of its lazy call-by-value reduction. Moreover, when the typing tree is minimal, such a bound becomes the exact length of the reduction

    Reversing Single Sessions

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    Session-based communication has gained a widespread acceptance in practice as a means for developing safe communicating systems via structured interactions. In this paper, we investigate how these structured interactions are affected by reversibility, which provides a computational model allowing executed interactions to be undone. In particular, we provide a systematic study of the integration of different notions of reversibility in both binary and multiparty single sessions. The considered forms of reversibility are: one for completely reversing a given session with one backward step, and another for also restoring any intermediate state of the session with either one backward step or multiple ones. We analyse the costs of reversing a session in all these different settings. Our results show that extending binary single sessions to multiparty ones does not affect the reversibility machinery and its costs

    Poisoning with “cafetillo” (Cassia occidentalis) in cattle from Northeastern Argentina.

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    Se reportan dos episodios espontáneos de intoxicación con Cassia occidentalis en bovinos de las provincias de Corrientes y Chaco, Argentina. Los accidentes ocurrieron por ingestión de forraje contaminado por la leguminosa tóxica y causaron la muerte de 60 animales. El cuadro clínico se caracterizó por anorexia, diarrea, deshidratación, temblores musculares, marcha tambaleante, decúbito esternal o lateral, pedaleo, opistótonos, disnea y muerte. En el contenido ruminal se hallaron vainas y semillas de C. occidentalis. La patología clínica reveló signos de inflamación aguda y/o necrosis tisular (leucocitosis neutrofílica) con anemia concomitante (en algunos casos enmascarada por hemoconcentración, con aumento de proteínas totales). Las alteraciones bioquímicas coincidieron con los cambios histopatológicos verificados. El miocardio y los músculos de la pelvis y miembros posteriores revelaron áreas de necrosis coagulativa (rabdomiólisis), en consonancia con los aumentos séricos de las actividades CPK, LDH y AST. La hepatomegalia y el cambio de coloración del hígado correlacionaron con el hallazgo microscópico de degeneración grasa periportal y necrosis coagulativa centrolobulillar, cuadro compatible con el daño hepático indicado por la disminución de la albuminemia y las elevaciones séricas de globulinas, bilirrubina y enzimas ALP, GGT y AST. Los riñones, edematosos, revelaron tumefacción de células epiteliales tubulares y obstrucción de túbulos corticales y medulares por cilindros hialinos. Estas alteraciones renales coincidieron con los aumentos séricos de urea, creatinina y fósforo inorgánico, así como los hallazgos de proteinuria, leucocituria, cilindruria y hematuria (mioglobinuria?). La posibilidad de intoxicación por C. occidentalisdebe tenerse en cuenta al momento de establecer el diagnóstico de bovinos que cursan con síntomas gastrointestinales, musculares, hepáticos, respiratorios y renales.Two spontaneous episodes of poisoning with Cassia occidentalis in cattle from Corrientes and Chaco (Argentina), are reported. Accidents were due to the ingestion of forage contaminated with the toxic leguminous and 60 animals died. Signology was characterized by anorexy, diarrhea, dehydration, muscular tremors, wobbly march, sternal or lateral decubitus, pedalling, opisthotonos, dyspnea and death. Pods and seeds of C. occidentalis were found in rumen content. Acute inflammation and/or tissular necrosis (neutrophilic leukocytosis) with concomitant anemia (in some cases masked by hemoconcentration, with increase of total proteins) were revealed by clinical pathology. Biochemical alterations were in concordance with the histopathological changes. Myocardium as well as muscles from pelvis and back legs revealed coagulative necrosis areas (rhabdomyolysis), with increased CPK, LDH and AST levels. Hepatomegalia and liver color alteration correlated with the microscopic findings of fatty periportal degeneration and coagulative centrilobular necrosis, alterations compatible with hepatic damage indicated by decrease of serum albumin and increments of globulins, bilirubin and ALP, GGT and AST enzymes. Kidneys were edematous and revealed swelling of tubular epithelial cells and obstruction of cortical and medullar tubules by hyaline cylinders. These renal alterations coincided with the serum increases of urea, creatinine and inorganic phosphorous, as well as the discoveries of proteinuria, leukocyturia, cylindruria and hematuria (myoglobinuria?). C. occidentalis poisoning in cattle may be considered as a possible diagnose when gastrointestinal, muscular, hepatic, respiratory and renal symptoms are present at the same time.Fil: Mussart, Norma Beatriz. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Koza, G. A.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Lértora, J.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Álvarez Chamale, G. M.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Coppo, J. A.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; Argentin
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