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CVC: a Cooperating Validity Checker
 In 14th International Conference on ComputerAided Verification
, 2002
"... Decision procedures for decidable logics and logical theories have proven to be useful tools in verification. This paper describes the CVC ("Cooperating Validity Checker") decision procedure. CVC implements a framework for combining subsidiary decision procedures for certain logical theories into a ..."
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Cited by 113 (18 self)
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Decision procedures for decidable logics and logical theories have proven to be useful tools in verification. This paper describes the CVC ("Cooperating Validity Checker") decision procedure. CVC implements a framework for combining subsidiary decision procedures for certain logical theories into a decision procedure for the theories' union. Subsidiary decision procedures for theories of arrays, inductive datatypes, and linear real arithmetic are currently implemented. Other notable features of CVC are the incorporation of the highperformance Cha solver for propositional reasoning, and the ability to produce independently checkable proofs for valid formulas.
Lazy theorem proving for bounded model checking over infinite domains
, 2002
"... Abstract. We investigate the combination of propositional SAT checkers with domainspecific theorem provers as a foundation for bounded model checking over infinite domains. Given a program M over an infinite state type, a linear temporal logic formula ' with domainspecific constraints over program ..."
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Cited by 74 (11 self)
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Abstract. We investigate the combination of propositional SAT checkers with domainspecific theorem provers as a foundation for bounded model checking over infinite domains. Given a program M over an infinite state type, a linear temporal logic formula ' with domainspecific constraints over program states, and an upper bound k, our procedure determines if there is a falsifying path of length k to the hypothesis that M satisfies the specification '. This problem can be reduced to the satisfiability of Boolean constraint formulas. Our verification engine for these kinds of formulas is lazy in that propositional abstractions of Boolean constraint formulas are incrementally refined by generating lemmas on demand from an automated analysis of spurious counterexamples using theorem proving. We exemplify bounded model checking for timed automata and for RTL level descriptions, and investigate the lazy integration of SAT solving and theorem proving. 1 Introduction Model checking decides the problem of whether a system satisfies a temporal logic property by exploring the underlying state space. It applies primarily to finitestate systems but also to certain infinitestate systems, and the state space can be represented in symbolic or explicit form. Symbolic model checking has traditionally employed a boolean representation of state sets using binary decision diagrams (BDD) [4] as a way of checking temporal properties, whereas explicitstate model checkers enumerate the set of reachable states of the system.
Strategies for Combining Decision Procedures
, 2003
"... Implementing efficient algorithms for combining decision procedures has been a challenge and their correctness precarious. In this paper we describe an inference system that has the classical NelsonOppen procedure at its core and includes several optimizations: variable abstraction with sharing, ca ..."
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Cited by 13 (2 self)
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Implementing efficient algorithms for combining decision procedures has been a challenge and their correctness precarious. In this paper we describe an inference system that has the classical NelsonOppen procedure at its core and includes several optimizations: variable abstraction with sharing, canonization of terms at the theory level, and Shostak's streamlined generation of new equalities for theories with solvers. The transitions of our system are finegrained enough to model most of the mechanisms currently used in designing combination procedures. In particular, with a simple language of regular expressions we are able to describe several combination algorithms as strategies for our inference system, from the basic NelsonOppen to the very highly optimized one recently given by Shankar and Rueß. Presenting the basic system at a high level of generality and nondeterminism allows transparent correctness proofs that can be extended in a modular fashion when new features are introduced in the system. Similarly, the correctness proof of any new strategy requires only minimal additional proof effort.
Revisiting Positive Equality
 IN TOOLS AND ALGORITHMS FOR THE CONSTRUCTION AND ANALYSIS OF SYSTEMS, VOLUME 2988 OF LNCS
, 2004
"... This paper provides a stronger result for exploiting positive equality in the logic of Equality with Uninterpreted Functions (EUF). Positive ..."
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Cited by 7 (2 self)
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This paper provides a stronger result for exploiting positive equality in the logic of Equality with Uninterpreted Functions (EUF). Positive