12,394 research outputs found

    Logic-Based Specification Languages for Intelligent Software Agents

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    The research field of Agent-Oriented Software Engineering (AOSE) aims to find abstractions, languages, methodologies and toolkits for modeling, verifying, validating and prototyping complex applications conceptualized as Multiagent Systems (MASs). A very lively research sub-field studies how formal methods can be used for AOSE. This paper presents a detailed survey of six logic-based executable agent specification languages that have been chosen for their potential to be integrated in our ARPEGGIO project, an open framework for specifying and prototyping a MAS. The six languages are ConGoLog, Agent-0, the IMPACT agent programming language, DyLog, Concurrent METATEM and Ehhf. For each executable language, the logic foundations are described and an example of use is shown. A comparison of the six languages and a survey of similar approaches complete the paper, together with considerations of the advantages of using logic-based languages in MAS modeling and prototyping.Comment: 67 pages, 1 table, 1 figure. Accepted for publication by the Journal "Theory and Practice of Logic Programming", volume 4, Maurice Bruynooghe Editor-in-Chie

    Meta-F*: Proof Automation with SMT, Tactics, and Metaprograms

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    We introduce Meta-F*, a tactics and metaprogramming framework for the F* program verifier. The main novelty of Meta-F* is allowing the use of tactics and metaprogramming to discharge assertions not solvable by SMT, or to just simplify them into well-behaved SMT fragments. Plus, Meta-F* can be used to generate verified code automatically. Meta-F* is implemented as an F* effect, which, given the powerful effect system of F*, heavily increases code reuse and even enables the lightweight verification of metaprograms. Metaprograms can be either interpreted, or compiled to efficient native code that can be dynamically loaded into the F* type-checker and can interoperate with interpreted code. Evaluation on realistic case studies shows that Meta-F* provides substantial gains in proof development, efficiency, and robustness.Comment: Full version of ESOP'19 pape

    TRX: A Formally Verified Parser Interpreter

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    Parsing is an important problem in computer science and yet surprisingly little attention has been devoted to its formal verification. In this paper, we present TRX: a parser interpreter formally developed in the proof assistant Coq, capable of producing formally correct parsers. We are using parsing expression grammars (PEGs), a formalism essentially representing recursive descent parsing, which we consider an attractive alternative to context-free grammars (CFGs). From this formalization we can extract a parser for an arbitrary PEG grammar with the warranty of total correctness, i.e., the resulting parser is terminating and correct with respect to its grammar and the semantics of PEGs; both properties formally proven in Coq.Comment: 26 pages, LMC

    Features and Fluents for Logic Programming: Non-simulative Algebraic Semantics

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    A Non-simulative Algebraic Semantics is defined and its range of applicability is proven to be the K-RACi class of the Features and Fluents framework. The comparative assessment reveals the semantics epistemologically equivalent and ontologically stronger than the Abductive Logic Programming, the Action Description Language A and the PMON entailment. The semantics is shown to be decidable

    Competition as rational action : why young children cannot appreciate competitive games

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    Understanding rational actions requires perspective taking both with respect to means and with respect to objectives. This study addresses the question of whether the two kinds of perspective taking develop simultaneously or in sequence. It is argued that evidence from competitive behavior is best suited for settling this issue. A total of 71 kindergarten children between 3 and 5 years of age participated in a competitive game of dice and were tested on two traditional false belief stories as well as on several control tasks (verbal intelligence, inhibitory control, and working memory). The frequency of competitive poaching moves in the game correlated with correct predictions of mistaken actions in the false belief task. Hierarchical linear regression after controlling for age and control variables showed that false belief understanding significantly predicted the amount of poaching moves. The results speak for an interrelated development of the capacity for “instrumental” and “telic” perspective taking. They are discussed in the light of teleology as opposed to theory use and simulation

    Abduction in Well-Founded Semantics and Generalized Stable Models

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    Abductive logic programming offers a formalism to declaratively express and solve problems in areas such as diagnosis, planning, belief revision and hypothetical reasoning. Tabled logic programming offers a computational mechanism that provides a level of declarativity superior to that of Prolog, and which has supported successful applications in fields such as parsing, program analysis, and model checking. In this paper we show how to use tabled logic programming to evaluate queries to abductive frameworks with integrity constraints when these frameworks contain both default and explicit negation. The result is the ability to compute abduction over well-founded semantics with explicit negation and answer sets. Our approach consists of a transformation and an evaluation method. The transformation adjoins to each objective literal OO in a program, an objective literal not(O)not(O) along with rules that ensure that not(O)not(O) will be true if and only if OO is false. We call the resulting program a {\em dual} program. The evaluation method, \wfsmeth, then operates on the dual program. \wfsmeth{} is sound and complete for evaluating queries to abductive frameworks whose entailment method is based on either the well-founded semantics with explicit negation, or on answer sets. Further, \wfsmeth{} is asymptotically as efficient as any known method for either class of problems. In addition, when abduction is not desired, \wfsmeth{} operating on a dual program provides a novel tabling method for evaluating queries to ground extended programs whose complexity and termination properties are similar to those of the best tabling methods for the well-founded semantics. A publicly available meta-interpreter has been developed for \wfsmeth{} using the XSB system.Comment: 48 pages; To appear in Theory and Practice in Logic Programmin
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