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1984 | Buch

Foundations of Logic Programming

verfasst von: John Wylie Lloyd

Verlag: Springer Berlin Heidelberg

Buchreihe : Symbolic Computation

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Über dieses Buch

This book gives an account oC the mathematical Coundations oC logic programming. I have attempted to make the book selC-contained by including prooCs of almost all the results needed. The only prerequisites are some Camiliarity with a logic programming language, such as PROLOG, and a certain mathematical maturity. For example, the reader should be Camiliar with induction arguments and be comCortable manipulating logical expressions. Also the last chapter assumes some acquaintance with the elementary aspects of metric spaces, especially properties oC continuous mappings and compact spaces. Chapter 1 presents the declarative aspects of logic programming. This chapter contains the basic material Crom first order logic and fixpoint theory which will be required. The main concepts discussed here are those oC a logic program, model, correct answer substitution and fixpoint. Also the unification algorithm is discussed in some detail. Chapter 2 is concerned with the procedural semantics oC logic programs. The declarative concepts are implemented by means oC a specialized Corm oC resolution, called SLD-resolution. The main results of this chapter concern the soundness and completeness oC SLD-resolution and the independence oC the computation rule. We also discuss the implications of omitting the occur check from PROLOG implementations. Chapter 3 discusses negation. Current PROLOG systems implement a form of negation by means of the negation as failure rule. The main results of this chapter are the soundness and completeness oC the negation as failure rule.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Declarative Semantics
Abstract
This chapter presents the declarative semantics of logic programs. After a brief introduction, the basic syntax and terminology of logic programs is introduced. We then discuss interpretations and models of logic programs. These provide the declarative semantics. Then the key concept of a correct answer substitution is introduced. This provides a declarative understanding of the desired output from a program and a goal. The basic fixpoint results are then proved and the chapter culminates with a fixpoint characterization of the least Herbrand model of a program.
John Wylie Lloyd
Chapter 2. Procedural Semantics
Abstract
This chapter is concerned with the procedural semantics of logic programs. The procedural counterpart of a correct answer substitution is a computed answer substitution, which is defined using SLD-resolution. We prove that every computed answer substitution is correct and that every correct answer substitution is an instance of a computed answer substitution. This establishes the soundness and completeness of SLD-resolution. The other important result established is the independence of the computation rule. Two pragmatic aspects of PROLOG implementations are also discussed. These are the omission of the occur check from the unification algorithm and the control facility, cut.
John Wylie Lloyd
Chapter 3. Negation
Abstract
In this chapter, we study various forms of negation. Since only positive information can be a logical consequence of a program, special rules are needed to deduce negative information. The most important of these rules are the closed world assumption and the negation as failure rule. The major results of this chapter are the soundness and completeness of the negation as failure rule.
John Wylie Lloyd
Chapter 4. Perpetual Processes
Abstract
A perpetual process is a program which does not terminate and yet is doing useful computation, in some sense. With the advent of PROLOG systems for concurrent applications [11], [12], [54], especially operating systems, more and more programs will be of this type. Unfortunately, the semantics for logic programs developed in chapters 1 and 2 does not apply to perpetual processes, simply because they do not terminate. Starting from the pioneering work of Andreka, van Emden, Nemeti and Tiuryn [1], we discuss in this chapter the basic results of a semantics for perpetual processes.
John Wylie Lloyd
Backmatter
Metadaten
Titel
Foundations of Logic Programming
verfasst von
John Wylie Lloyd
Copyright-Jahr
1984
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-642-96826-6
Print ISBN
978-3-642-96828-0
DOI
https://doi.org/10.1007/978-3-642-96826-6