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23
Model Checking Programs
, 2003
"... The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this pape ..."
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Cited by 474 (61 self)
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The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this paper we will attempt to give convincing arguments for why we believe it is time for the formal methods community to shift some of its attention towards the analysis of programs written in modern programming languages. In keeping with this philosophy we have developed a verification and testing environment for Java, called Java PathFinder (JPF), which integrates model checking, program analysis and testing. Part of this work has consisted of building a new Java Virtual Machine that interprets Java bytecode. JPF uses state compression to handle big states, and partial order and symmetry reduction, slicing, abstraction, and runtime analysis techniques to reduce the state space. JPF has been applied to a realtime avionics operating system developed at Honeywell, illustrating an intricate error, and to a model of a spacecraft controller, illustrating the combination of abstraction, runtime analysis, and slicing with model checking.
Experiments in Theorem Proving and Model Checking for Protocol Verification
, 1996
"... . Communication protocols pose interesting and difficult challenges for verification technologies. The state spaces of interesting protocols are either infinite or too large for finitestate verification techniques like model checking and state exploration. Theorem proving is also not effective sinc ..."
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Cited by 76 (12 self)
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. Communication protocols pose interesting and difficult challenges for verification technologies. The state spaces of interesting protocols are either infinite or too large for finitestate verification techniques like model checking and state exploration. Theorem proving is also not effective since the formal correctness proofs of these protocols can be long and complicated. We describe a series of protocol verification experiments culminating in a methodology where theorem proving is used to abstract out the sources of unboundedness in the protocol to yield a skeletal protocol that can be verified using model checking. Our experiments focus on the Philips bounded retransmission protocol originally studied by Groote and van de Pol and by Helmink, Sellink, and Vaandrager. First, a scaleddown version of the protocol is analyzed using the MurOE state exploration tool as a debugging aid and then translated into the PVS specification language. The PVS verification of the generalized prot...
Typing Algorithm in Type Theory with Inheritance
 Proc of POPL'97
, 1997
"... We propose and study a new typing algorithm for dependent type theory. This new algorithm typechecks more terms by using inheritance between classes. This inheritance mechanism turns out to be powerful: it supports multiple inheritance, classes with parameters and uses new abstract classes FUNCLASS ..."
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Cited by 42 (0 self)
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We propose and study a new typing algorithm for dependent type theory. This new algorithm typechecks more terms by using inheritance between classes. This inheritance mechanism turns out to be powerful: it supports multiple inheritance, classes with parameters and uses new abstract classes FUNCLASS and SORTCLASS (respectively classes of functions and sorts). We also defines classes as records, particularily suitable for the formal development of mathematical theories. This mechanism, implemented in the proof checker Coq, can be adapted to all typed calculus. 1 Introduction In the last years, proof checkers based on type theory appeared as convincing systems to formalize mathematics (especially constructive mathematics) and to prove correctness of software and hardware. In a proof checker, one can interactively build definitions, statements and proofs. The system is then able to check automatically whether the definitions are wellformed and the proofs are correct. Modern systems ar...
Focus points and convergent process operators: A proof strategy for protocol verification
, 1995
"... We present a strategy for finding algebraic correctness proofs for communication systems. It is described in the setting of µCRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [ ..."
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Cited by 39 (11 self)
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We present a strategy for finding algebraic correctness proofs for communication systems. It is described in the setting of µCRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [4] and [10], but was not explicitly identified as such. Moreover, the protocols that were verified in these papers were rather complex, so that the general picture was obscured by the amount of details. In this paper, the proof strategy is materialised in the form of definitions and theorems. These results reduce a large part of protocol verification to a number of trivial facts concerning data parameters occurring in implementation and specification. This greatly simplifies protocol verifications and makes our approach amenable to mechanical assistance � experiments in this direction seem promising. The strategy is illustrated by several small examples and one larger example, the Concurrent Alternating Bit Protocol (CABP). Although simple, this protocol contains a large amount of internal parallelism, so that all relevant issues make their appearance.
A module calculus for Pure Type Systems
, 1996
"... Several proofassistants rely on the very formal basis of Pure Type Systems. However, some practical issues raised by the development of large proofs lead to add other features to actual implementations for handling namespace management, for developing reusable proof libraries and for separate verif ..."
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Cited by 23 (3 self)
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Several proofassistants rely on the very formal basis of Pure Type Systems. However, some practical issues raised by the development of large proofs lead to add other features to actual implementations for handling namespace management, for developing reusable proof libraries and for separate verification of distincts parts of large proofs. Unfortunately, few theoretical basis are given for these features. In this paper we propose an extension of Pure Type Systems with a module calculus adapted from SMLlike module systems for programming languages. Our module calculus gives a theoretical framework addressing the need for these features. We show that our module extension is conservative, and that type inference in the module extension of a given PTS is decidable under some hypotheses over the considered PTS.
On Proving Safety Properties by Integrating Static Analysis, Theorem Proving and Abstraction
 TACAS '99
, 1999
"... We present a new approach for proving safety properties of reactive systems, based on tight interaction between static analysis, theorem proving and abstraction techniques. The method incrementally constructs a proof or finds a counterexample. Every step consists of applying one of the techniques an ..."
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Cited by 19 (0 self)
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We present a new approach for proving safety properties of reactive systems, based on tight interaction between static analysis, theorem proving and abstraction techniques. The method incrementally constructs a proof or finds a counterexample. Every step consists of applying one of the techniques and makes constructive use of information obtained from failures in previous steps. The amount of user intervention is limited and is highly guided by the system at each step. We demonstrate the method on three simple examples, and show that by using it one can prove more properties than by using each component as a standalone.
GUSTT: An Amorphous Slicing System which Combines Slicing and Transformation
 In 1 st Workshop on Analysis, Slicing, and Transformation (AST 2001
, 2001
"... This paper presents a system for amorphous program slicing which combines slicing and transformation to achieve thinner slices than are possible using conventional syntaxpreserving slicing. The approach involves the validation of the transformation and slicing steps using the Coq proof assistant, t ..."
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Cited by 11 (8 self)
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This paper presents a system for amorphous program slicing which combines slicing and transformation to achieve thinner slices than are possible using conventional syntaxpreserving slicing. The approach involves the validation of the transformation and slicing steps using the Coq proof assistant, thereby guaranteeing the correctness of the amorphous slices produced. The combined application of slicing and transformation is illustrated with a simple case study.
Software Verification and System Assurance
, 2009
"... Littlewood [1] introduced the idea that software may be possibly perfect and that we can contemplate its probability of (im)perfection. We review this idea and show how it provides a bridge between correctness, which is the goal of software verification (and especially formal verification), and the ..."
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Cited by 8 (3 self)
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Littlewood [1] introduced the idea that software may be possibly perfect and that we can contemplate its probability of (im)perfection. We review this idea and show how it provides a bridge between correctness, which is the goal of software verification (and especially formal verification), and the probabilistic properties such as reliability that are the targets for systemlevel assurance. We enumerate the hazards to formal verification, consider how each of these may be countered, and propose relative weightings that an assessor may employ in assigning a probability of perfection.
Reasoning about the Reliability Of Diverse TwoChannel Systems In which One Channel is “Possibly Perfect”
, 2009
"... should appear on the left and oddnumbered pages on the right when opened as a doublepage This report refines and extends an earlier paper by the first author [25]. It considers the problem of reasoning about the reliability of faulttolerant systems with two “channels” (i.e., components) of which o ..."
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Cited by 8 (2 self)
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should appear on the left and oddnumbered pages on the right when opened as a doublepage This report refines and extends an earlier paper by the first author [25]. It considers the problem of reasoning about the reliability of faulttolerant systems with two “channels” (i.e., components) of which one, A, because it is conventionally engineered and presumed to contain faults, supports only a claim of reliability, while the other, B, by virtue of extreme simplicity and extensive analysis, supports a plausible claim of “perfection.” We begin with the case where either channel can bring the system to a safe state. The reasoning about system probability of failure on demand (pfd) is divided into two steps. The first concerns aleatory uncertainty about (i) whether channel A will fail on a randomly selected demand and (ii) whether channel B is imperfect. It is shown that, conditional upon knowing pA (the probability that A fails on a randomly selected demand) and pB (the probability that channel B is imperfect), a conservative bound on the probability that the system fails on a randomly selected demand is simply pA × pB. That is, there is conditional independence between the events “A fails ” and “B is imperfect. ” The second
Writing PVS proof strategies
 Design and Application of Strategies/Tactics in Higher Order Logics (STRATA 2003), number CP2003212448 in NASA Conference Publication
, 2003
"... Abstract. PVS (Prototype Verification System) is a comprehensive framework for writing formal logical specifications and constructing proofs. An interactive proof checker is a key component of PVS. The capabilities of this proof checker can be extended by defining proof strategies that are similar t ..."
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Cited by 6 (1 self)
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Abstract. PVS (Prototype Verification System) is a comprehensive framework for writing formal logical specifications and constructing proofs. An interactive proof checker is a key component of PVS. The capabilities of this proof checker can be extended by defining proof strategies that are similar to LCFstyle tactics. Commonly used proof strategies include those for discharging typechecking proof obligations, simplification and rewriting using decision procedures, and various forms of induction. We describe the basic building blocks of PVS proof strategies and provide a pragmatic guide for writing sophisticated strategies. 1