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The Semantics of Predicate Logic as a Programming Language
 Journal of the ACM
, 1976
"... ABSTRACT Sentences in firstorder predicate logic can be usefully interpreted as programs In this paper the operational and fixpomt semantics of predicate logic programs are defined, and the connections with the proof theory and model theory of logic are investigated It is concluded that operational ..."
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Cited by 707 (16 self)
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ABSTRACT Sentences in firstorder predicate logic can be usefully interpreted as programs In this paper the operational and fixpomt semantics of predicate logic programs are defined, and the connections with the proof theory and model theory of logic are investigated It is concluded that operational semantics is a part of proof theory and that fixpolnt semantics is a special case of modeltheoret:c semantics KEY WORDS AND PHRASES predicate logic as a programming language, semantics of programming languages, resolution theorem proving, operaUonal versus denotatlonal semantics, SLresoluuon, flxpomt characterization
Definitional interpreters for higherorder programming languages
 Reprinted from the proceedings of the 25th ACM National Conference
, 1972
"... Abstract. Higherorder programming languages (i.e., languages in which procedures or labels can occur as values) are usually defined by interpreters that are themselves written in a programming language based on the lambda calculus (i.e., an applicative language such as pure LISP). Examples include ..."
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Cited by 299 (2 self)
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Abstract. Higherorder programming languages (i.e., languages in which procedures or labels can occur as values) are usually defined by interpreters that are themselves written in a programming language based on the lambda calculus (i.e., an applicative language such as pure LISP). Examples include McCarthy’s definition of LISP, Landin’s SECD machine, the Vienna definition of PL/I, Reynolds ’ definitions of GEDANKEN, and recent unpublished work by L. Morris and C. Wadsworth. Such definitions can be classified according to whether the interpreter contains higherorder functions, and whether the order of application (i.e., call by value versus call by name) in the defined language depends upon the order of application in the defining language. As an example, we consider the definition of a simple applicative programming language by means of an interpreter written in a similar language. Definitions in each of the above classifications are derived from one another by informal but constructive methods. The treatment of imperative features such as jumps and assignment is also discussed.
Semantics of Types for Mutable State
, 2004
"... Proofcarrying code (PCC) is a framework for mechanically verifying the safety of machine language programs. A program that is successfully verified by a PCC system is guaranteed to be safe to execute, but this safety guarantee is contingent upon the correctness of various trusted components. For in ..."
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Cited by 55 (5 self)
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Proofcarrying code (PCC) is a framework for mechanically verifying the safety of machine language programs. A program that is successfully verified by a PCC system is guaranteed to be safe to execute, but this safety guarantee is contingent upon the correctness of various trusted components. For instance, in traditional PCC systems the trusted computing base includes a large set of lowlevel typing rules. Foundational PCC systems seek to minimize the size of the trusted computing base. In particular, they eliminate the need to trust complex, lowlevel type systems by providing machinecheckable proofs of type soundness for real machine languages. In this thesis, I demonstrate the use of logical relations for proving the soundness of type systems for mutable state. Specifically, I focus on type systems that ensure the safe allocation, update, and reuse of memory. For each type in the language, I define logical relations that explain the meaning of the type in terms of the operational semantics of the language. Using this model of types, I prove each typing rule as a lemma. The major contribution is a model of System F with general references — that is, mutable cells that can hold values of any closed type including other references, functions, recursive types, and impredicative quantified types. The model is based on ideas from both possible worlds and the indexed model of Appel and McAllester. I show how the model of mutable references is encoded in higherorder logic. I also show how to construct an indexed possibleworlds model for a von Neumann machine. The latter is used in the Princeton Foundational PCC system to prove type safety for a fullfledged lowlevel typed assembly language. Finally, I present a semantic model for a region calculus that supports typeinvariant references as well as memory reuse. iii
Proving Theorems about LISP Functions
, 1975
"... Program verification is the idea that properties of programs can be precisely stated and proved in the mathematical sense. In this paper, some simple heuristics combining evaluation and mathematical induction are described, which the authors have implemented in a program that automatically proves a ..."
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Cited by 48 (2 self)
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Program verification is the idea that properties of programs can be precisely stated and proved in the mathematical sense. In this paper, some simple heuristics combining evaluation and mathematical induction are described, which the authors have implemented in a program that automatically proves a wide variety of theorems about recursive LISP functions. The method the program uses to generate induction formulas is described at length. The theorems proved by the program include that REVERSE is its own inverse and that a particular SORT program is correct. A list of theorems proved by the program is given. key words and phrases: LISP, automatic theoremproving, structural induction, program verification cr categories: 3.64, 4.22, 5.21 1 Introduction We are concerned with proving theorems in a firstorder theory of lists, akin to the elementary theory of numbers. We use a subset of LISP as our language because recursive list processing functions are easy to write in LISP and because ...
Modal Logics and muCalculi: An Introduction
, 2001
"... We briefly survey the background and history of modal and temporal logics. We then concentrate on the modal mucalculus, a modal logic which subsumes most other commonly used logics. We provide an informal introduction, followed by a summary of the main theoretical issues. We then look at modelchec ..."
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Cited by 44 (3 self)
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We briefly survey the background and history of modal and temporal logics. We then concentrate on the modal mucalculus, a modal logic which subsumes most other commonly used logics. We provide an informal introduction, followed by a summary of the main theoretical issues. We then look at modelchecking, and finally at the relationship of modal logics to other formalisms.
A Coinduction Principle for Recursively Defined Domains
 THEORETICAL COMPUTER SCIENCE
, 1992
"... This paper establishes a new property of predomains recursively defined using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest fixed point of a certain monotone operator ..."
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Cited by 40 (3 self)
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This paper establishes a new property of predomains recursively defined using the cartesian product, disjoint union, partial function space and convex powerdomain constructors. We prove that the partial order on such a recursive predomain D is the greatest fixed point of a certain monotone operator associated to D. This provides a structurally defined family of proof principles for these recursive predomains: to show that one element of D approximates another, it suffices to find a binary relation containing the two elements that is a postfixed point for the associated monotone operator. The statement of the proof principles is independent of any of the various methods available for explicit construction of recursive predomains. Following Milner and Tofte [10], the method of proof is called coinduction. It closely resembles the way bisimulations are used in concurrent process calculi [9]. Two specific instances of the coinduction principle already occur in work of Abramsky [2, 1] in the form of `internal full abstraction' theorems for denotational semantics of SCCS and the lazy lambda calculus. In the first case postfixed binary relations are precisely Abramsky's partial bisimulations, whereas in the second case they are his applicative bisimulations. The coinduction principle also provides an apparently useful tool for reasoning about equality of elements of recursively defined datatypes in (strict or lazy) higher order functional programming languages.
A Comparative Study of Symbolic Algorithms for the Computation of Fair Cycles
"... Detection of fair cycles is an important task of many model checking algorithms. When the transition system is represented symbolically, the standard approach to fair cycle detection is the one of Emerson and Lei. In the last decade variants of this algorithm and an alternative method based on stron ..."
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Cited by 34 (7 self)
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Detection of fair cycles is an important task of many model checking algorithms. When the transition system is represented symbolically, the standard approach to fair cycle detection is the one of Emerson and Lei. In the last decade variants of this algorithm and an alternative method based on strongly connected component decomposition have been proposed. We present a taxonomy of these techniques and compare representatives of each major class on a collection of reallife examples. Our results indicate that the EmersonLei procedure is the fastest, but other algorithms tend to generate shorter counterexamples.
A Stratified Semantics of General References Embeddable in HigherOrder Logic (Extended Abstract)
, 2002
"... Amal J. Ahmed Andrew W. Appel # Roberto Virga Princeton University {amal,appel,rvirga}@cs.princeton.edu Abstract We demonstrate a semantic model of general references  that is, mutable memory cells that may contain values of any (staticallychecked) closed type, including other references. Our mo ..."
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Cited by 30 (8 self)
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Amal J. Ahmed Andrew W. Appel # Roberto Virga Princeton University {amal,appel,rvirga}@cs.princeton.edu Abstract We demonstrate a semantic model of general references  that is, mutable memory cells that may contain values of any (staticallychecked) closed type, including other references. Our model is in terms of execution sequences on a von Neumann machine
What can knowledge representation do for semistructured data
 In Proc. of the 15th Nat. Conf. on Artificial Intelligence (AAAI98
, 1998
"... The problem of modeling semistructured data is important in many application areas such as multimedia data management, biological databases, digital libraries, and data integration. Graph schemas (Buneman et al. 1997) have been proposed recently as a simple and elegant formalism for representing se ..."
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Cited by 27 (10 self)
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The problem of modeling semistructured data is important in many application areas such as multimedia data management, biological databases, digital libraries, and data integration. Graph schemas (Buneman et al. 1997) have been proposed recently as a simple and elegant formalism for representing semistructured data. In this model, schemas are represented as graphs whose edges are labeled with unary formulae of a theory, and the notions of conformance of a database to a schema and of subsumption between two schemas are defined in terms of a simulation relation. Several authors have stressed the need of extending graph schemas with various types of constraints, such as edge existence and constraints on the number of outgoing edges. In this paper we analyze the appropriateness of various knowledge representation formalisms for representing and reasoning about graph schemas extended with constraints. We argue that neither First Order Logic, nor Logic Programming nor Framebased languages are satisfactory for this purpose, and present a solution based on very expressive Description Logics. We provide techniques and complexity analysis for the problem of deciding schema subsumption and conformance in various interesting cases, that differ by the expressive power in the specification of constraints.