Verificación de Sistemas Basada en Teoría de Tipos. System verification in type theory

Este proyecto se enmarca en la utlización de métodos formales (más precisamente, en la utilización de teoría de tipos) para garantizar la ausencia de errores en programas. Por un lado se plantea el diseño de nuevos algoritmos de chequeo de tipos. Para ello, se proponen nuevos algoritmos basados en la idea de normalización por evaluación que sean extensibles a otros sistemas de tipos. En el futuro próximo extenderemos resultados que hemos conseguido recientemente [16,17] para obtener: una simplificación de los trabajos realizados para sistemas sin regla eta (acá se estudiarán dos sistemas: a la Martin Löf y a la PTS), la formulación de estos chequeadores para sistemas con variables, generalizar la noción de categoría con familia utilizada para dar semántica a teoría de tipos, obtener una formulación categórica de la noción de normalización por evaluación y finalmente, aplicar estos algoritmos a sistemas con reescrituras. Para los primeros resultados esperados mencionados, nos proponemos como método adaptar las pruebas de [16,17] a los nuevos sistemas. La importancia radica en que permitirán tornar más automatizables (y por ello, más fácilmente utilizables) los asistentes de demostración basados en teoría de tipos. Por otro lado, se utilizará la teoría de tipos para certificar compiladores, intentando llevar adelante la propuesta nunca explorada de [22] de utilizar un enfoque abstracto basado en categorías funtoriales. El método consistirá en certificar el lenguaje "Peal" [29] y luego agregar sucesivamente funcionalidad hasta obtener Forsythe [23]. En este período esperamos poder agregar varias extensiones. La importancia de este proyecto radica en que sólo un compilador certificado garantiza que un programa fuente correcto se compile a un programa objeto correcto. Es por ello, crucial para todo proceso de verificación que se base en verificar código fuente. Finalmente, se abordará la formalización de sistemas con session types. Los mismos han demostrado tener fallas en sus formulaciones [30], por lo que parece conveniente su formalización. Durante la marcha de este proyecto, esperamos tener alguna formalización que dé lugar a un algoritmo de chequeo de tipos y a demostrar las propiedades usuales de los sistemas. La contribución es arrojar un poco de luz sobre estas formulaciones cuyos errores revelan que el tema no ha adquirido aún suficiente madurez o comprensión por parte de la comunidad. This project is about using type theory to garantee program correctness. It follows three different directions: 1) Finding new type-checking algorithms based on normalization by evaluation. First, we would show that recent results like [16,17] extend to other type systems like: Martin-Löf´s type theory without eta rule, PTSs, type systems with variables (in addition to systems in [16,17] which are a la de Bruijn), systems with rewrite rules. This will be done by adjusting the proofs in [16,17] so that they apply to such systems as well. We will also try to obtain a more general definition of categories with families and normalization by evaluation, formulated in categorical terms. We expect this may turn proof-assistants more automatic and useful. 2) Exploring the proposal in [22] to compiler construction for Algol-like languages using functorial categories. According to [22] such approach is suitable for verifying compiler correctness, claim which was never explored. First, the language Peal [29] will be certified in type theory and we will gradually add funtionality to it until a correct compiler for the language Forsythe [23] is obtained. 3) Formilizing systems for session types. Several proposals have shown to be faulty [30]. This means that a formalization of it may contribute to the general understanding of session types.

Darwin and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions, by George John Romanes ...

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Darwin and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions, by George John Romanes ...

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Darwin and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions, by George John Romanes ...

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Socially integrative customer service (SICS) : identification of a symbiotic link with corporate social responsibility

The aim of this study is to answer the research question "can customer service be revitalised through identification of a symbiotic relationship with social responsibility, linked by people-centricity?" The concept of customer service remains weak and there has been a lack of attention to the underlying purpose: "to serve". To strengthen the theory the humanistic nature of the concept should be revised. Fundamental to this argument is the question of who is a customer? To fully discover the scope of the concept requires a broader or more specifically a societal view. Herein the theme of social corporate responsibility is critical to the recognition of the customer service network (CSN). This suggestion in isolation is useful but structural. Another aspect must be identified to validate the "service" ethos. Through this reasoning the relational theme (RT) provides for a mechanism for this to be achieved. Therefore the theory of socially integrative customer service is based on broadening and deepening the customer service concept. This study is illustrated in the context of the grocery retail sector in the Republic of Ireland. Four case studies are presented, three based on company-wide and in-store research and a fourth is a cross-company study. Results across companies indicate acceptance of the research question and show evidence to validate SICS. There is scope to further develop SICS and to build on the CSN and the RT. Finally the concept of SICS provides for a diverse basis for further research. This theory does no purport to cause a paradigm shift but does add innovation to the body of knowledge. As is the hallmark of good theoretical development, the author has aimed to keep the philosophy simple.

A critique of the theory of evolution, by Thomas Hunt Morgan ... Lectures delivered at Princeton University, February 24, March 1, 8, 15, 1916.

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The mutation theory; experiments and observations on the origin of species in the vegetable kingdom, by Hugo de Vries ... tr. by Prof. J. B. Farmer and A. D. Darbishire ...

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