Bio: Jean-Jacques Lévy is an academic researcher from French Institute for Research in Computer Science and Automation. The author has contributed to research in topics: Lambda calculus & Operational semantics. The author has an hindex of 15, co-authored 20 publications receiving 2081 citations.
••01 Dec 1989
TL;DR: The λ&sgr;-calculus is a refinement of the λ-Calculus where substitutions are manipulated explicitly, and provides a setting for studying the theory of substitutions, with pleasant mathematical properties.
Abstract: The ls-calculus is a refinement of the l-calculus where substitutions are manipulated explicitly. The ls-calculus provides a setting for studying the theory of substitutions, with pleasant mathematical properties. It is also a useful bridge between the classical l-calculus and concrete implementations.
••26 Aug 1996
TL;DR: This work introduces a calculus for mobile agents and gives its chemical semantics, with a precise definition for migration, failure, and failure detection, and gives the encoding of the distributed calculus into the join-calculus.
Abstract: We introduce a calculus for mobile agents and give its chemical semantics, with a precise definition for migration, failure, and failure detection Various examples written in our calculus illustrate how to express remote executions, dynamic loading of remote resources and protocols with mobile agents We give the encoding of our distributed calculus into the join-calculus
01 Feb 1992
TL;DR: This paper connects and explains the geometry of interaction and Lamping's graphs, which offer a new understanding of computation, as well as ideas for efficient and correct implementations.
Abstract: Lamping discovered an optimal graph-reduction implementation of the l-calculus. Simultaneously, Girard invented the geometry of interaction, a mathematical foundation for operational semantics. In this paper, we connect and explain the geometry of interaction and Lamping's graphs. The geometry of interaction provides a suitable semantic basis for explaining and improving Lamping's system. On the other hand, graphs similar to Lamping's provide a concrete representation of the geometry of interaction. Together, they offer a new understanding of computation, as well as ideas for efficient and correct implementations.
TL;DR: The main new results of the paper are a confluent weak calculus of substitutions, where no variable clashes can be feared, and a conjecture raised in Abadi : λ&sgr;-calculus is not confluent (it is confluent on ground terms only).
Abstract: Categorical combinators [Curien 1986/1993; Hardin 1989; Yokouchi 1989] and more recently ls-calculus [Abadi 1991; Hardin and Le´vy 1989], have been introduced to provide an explicit treatment of substitutions in the l-calculus. We reintroduce here the ingredients of these calculi in a self-contained and stepwise way, with a special emphasis on confluence properties. The main new results of the paper with respect to Curien [1986/1993], Hardin , Abadi , and Hardin and Le´vy  are the following:(1) We present a confluent weak calculus of substitutions, where no variable clashes can be feared; (2) We solve a conjecture raised in Abadi : ls-calculus is not confluent (it is confluent on ground terms only).This unfortunate result is “repaired” by presenting a confluent version of ls-calculus, named the lEnv-caldulus in Hardin and Le´vy , called here the confluent ls-calculus.
••15 Jun 1996
TL;DR: This work addresses the problem of dependency analysis and caching in the context of the λ-calculus with a mechanism for keeping track of dependencies, and discusses how to use these dependencies in caching.
Abstract: We address the problem of dependency analysis and caching in the context of the λ-calculus. The dependencies of a λ-term are (roughly) the parts of the λ-term that contribute to the result of evaluating it. We introduce a mechanism for keeping track of dependencies, and discuss how to use these dependencies in caching.
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These
•01 Jan 2002
TL;DR: This text provides a comprehensive introduction both to type systems in computer science and to the basic theory of programming languages, with a variety of approaches to modeling the features of object-oriented languages.
Abstract: A type system is a syntactic method for automatically checking the absence of certain erroneous behaviors by classifying program phrases according to the kinds of values they compute. The study of type systems -- and of programming languages from a type-theoretic perspective -- has important applications in software engineering, language design, high-performance compilers, and security.This text provides a comprehensive introduction both to type systems in computer science and to the basic theory of programming languages. The approach is pragmatic and operational; each new concept is motivated by programming examples and the more theoretical sections are driven by the needs of implementations. Each chapter is accompanied by numerous exercises and solutions, as well as a running implementation, available via the Web. Dependencies between chapters are explicitly identified, allowing readers to choose a variety of paths through the material.The core topics include the untyped lambda-calculus, simple type systems, type reconstruction, universal and existential polymorphism, subtyping, bounded quantification, recursive types, kinds, and type operators. Extended case studies develop a variety of approaches to modeling the features of object-oriented languages.
TL;DR: Maude as discussed by the authors is a programming language whose modules are rewriting logic theories, which is defined and given denotational and operational semantics, and it provides a simple unification of concurrent programming with functional and object-oriented programming and supports high level declarative programming of concurrent systems.
01 Jan 1996
TL;DR: This book takes a novel approach to the understanding of object-oriented languages by introducing object calculi and developing a theory of objects around them, which covers both the semantics of objects and their typing rules.
Abstract: From the Publisher: Procedural languages are generally well understood. Their foundations have been cast in calculi that prove useful in matters of implementation and semantics. So far, an analogous understanding has not emerged for object-oriented languages. In this book the authors take a novel approach to the understanding of object-oriented languages by introducing object calculi and developing a theory of objects around them. The book covers both the semantics of objects and their typing rules, and explains a range of object-oriented concepts, such as self, dynamic dispatch, classes, inheritance, prototyping, subtyping, covariance and contravariance, and method specialization. Researchers and graduate students will find this an important development of the underpinnings of object-oriented programming.